tag:theconversation.com,2011:/us/topics/carcinogens-32783/articlesCarcinogens – The Conversation2023-08-10T20:00:53Ztag:theconversation.com,2011:article/2104622023-08-10T20:00:53Z2023-08-10T20:00:53ZWhat’s in vapes? Toxins, heavy metals, maybe radioactive polonium<figure><img src="https://images.theconversation.com/files/541174/original/file-20230804-29-77kck2.jpg?ixlib=rb-1.1.0&rect=1%2C1%2C997%2C664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-girl-smokes-disposable-electronic-cigarette-1943062066">Shutterstock</a></span></figcaption></figure><p>If you asked me what’s in e-cigarettes, disposable vapes or e-liquids, my short answer would be “we don’t fully know”.</p>
<p>The huge and increasing range of products and flavours on the market, changes to ingredients when they are heated or interact with each other, and inadequate labelling make this a complicated question to answer.</p>
<p><a href="https://www.annualreviews.org/doi/pdf/10.1146/annurev-anchem-061318-115329">Analytical chemistry</a>, including <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">my own team’s research</a>, gives some answers. But understanding the health impacts adds another level of complexity. E-cigarettes’ risk to health varies depending on <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.1c00070">many factors</a> including which device or flavours are used, and how people use them.</p>
<p>So vapers just don’t know what they’re inhaling and cannot be certain of the health impacts.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/no-vapes-arent-95-less-harmful-than-cigarettes-heres-how-this-decade-old-myth-took-off-203039">No, vapes aren't 95% less harmful than cigarettes. Here's how this decade-old myth took off</a>
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</em>
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<h2>What do we know?</h2>
<p>Despite these complexities, there are some consistencies between what different laboratories find.</p>
<p>Ingredients include nicotine, flavouring chemicals, and the liquids that carry them – primarily propylene glycol and glycerine.</p>
<p><a href="https://www.industrialchemicals.gov.au/sites/default/files/2020-08/Non-nicotine%20liquids%20for%20e-cigarette%20devices%20in%20Australia%20chemistry%20and%20health%20concerns%20%5BPDF%201.21%20MB%5D.pdf">Concerningly</a>, we also find volatile organic compounds, particulate matter and carcinogens (agents that can cause cancer), many of which we know are harmful. </p>
<p>Our <a href="https://www.mja.com.au/journal/2019/210/3/nicotine-and-other-potentially-harmful-compounds-nicotine-free-e-cigarette">previous</a> <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">research</a> also found 2-chlorophenol in about half of e-liquids users buy to top-up re-fillable e-cigarettes. This is one example of a chemical with no valid reason to be there. Globally, it’s <a href="https://pubchem.ncbi.nlm.nih.gov/compound/2-Chlorophenol#section=Hazard-Classes-and-Categories">classified</a> as “harmful if inhaled”. Its presence is likely due to contamination during manufacturing.</p>
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<strong>
Read more:
<a href="https://theconversation.com/many-e-cigarette-vaping-liquids-contain-toxic-chemicals-new-australian-research-169615">Many e-cigarette vaping liquids contain toxic chemicals: new Australian research</a>
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<h2>How about polonium?</h2>
<p>One potential ingredient that has been in the news in recent weeks is radioactive polonium-210, the same substance used to <a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">assassinate</a> former Russian spy Alexander Litvinenko in 2006. The Queensland government is <a href="https://www.abc.net.au/news/2023-07-26/queensland-scientists-test-vapes-for-polonium-210/102564282">now testing</a> vapes for it.</p>
<p>Polonium-210 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9207432/">can be found</a> in traditional cigarettes and other tobacco products. That’s because tobacco plants <a href="https://www.science.org/doi/abs/10.1126/science.153.3738.880">absorb it</a> and other radioactive materials from the soil, air and high-phosphate fertiliser.</p>
<p>Whether polonium-210 is found in aerosols produced by e-cigarettes remains to be seen. Although it is feasible if the glycerine in e-liquids comes from plants and similar fertilisers are used to grow them.</p>
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Read more:
<a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">Litvinenko poisoning: polonium explained</a>
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<h2>It’s not just the ingredients</h2>
<p>Aside from their ingredients, the materials e-cigarette devices are made from can end up in our bodies.</p>
<p><a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP2175">Toxic metals</a> and <a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP5686">related substances</a> such as arsenic, lead, chromium and nickel can be detected in both e-liquids and vapers’ urine, saliva and blood.</p>
<p>These substances can pose serious health risks (such as being carcinogenic). They can leach from several parts of an e-cigarette, including the heating coil, wires and soldered joints.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=1000&fit=clip"><img alt="Colourful, disposable vapes on a blue background" src="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Chemicals from the device itself can end up in our blood, urine and saliva.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/set-colorful-disposable-electronic-cigarettes-on-2065547126">Shutterstock</a></span>
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<strong>
Read more:
<a href="https://theconversation.com/we-asked-over-700-teens-where-they-bought-their-vapes-heres-what-they-said-190669">We asked over 700 teens where they bought their vapes. Here's what they said</a>
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<h2>That’s not all</h2>
<p>The process of heating e-liquids to create an inhalable aerosol also changes their chemical make-up to produce <a href="https://pubs.acs.org/doi/10.1021/acs.chemrestox.9b00410">degradation</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">products</a>. </p>
<p>These include:</p>
<ul>
<li><p>formaldehyde (a substance used to embalm dead bodies)</p></li>
<li><p>acetaldehyde (a key substance that contributes to a hangover after drinking alcohol)</p></li>
<li><p>acrolein (used as a chemical weapon in the first world war and now used as a herbicide).</p></li>
</ul>
<p>These chemicals are <a href="https://www.mdpi.com/2305-6304/10/12/714">often detected</a> in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6129974">e-cigarette samples</a>. However due to different devices and how the samples are collected, the <a href="https://ehjournal.biomedcentral.com/articles/10.1186/s12940-017-0249-x">levels measured</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">vary widely</a> between studies.</p>
<p>Often, the levels are very low, leading to proponents of vaping arguing e-cigarettes are far safer than tobacco smoking. </p>
<p>But this argument does not acknowledge that many e-cigarette users (particularly adolescents) <a href="https://www.tobaccoinaustralia.org.au/chapter-18-e-cigarettes/18-3-extent">were or are not cigarette smokers</a>, meaning a better comparison is between e-cigarette use and breathing “fresh” air. </p>
<p>An e-cigarette user is undoubtedly exposed to more toxins and harmful substances than a non-smoker. People who buy tobacco cigarettes are also confronted with a plethora of warnings about the hazards of smoking, while vapers generally are not.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/sex-and-lies-are-used-to-sell-vapes-online-even-we-were-surprised-at-the-marketing-tactics-we-found-200446">Sex and lies are used to sell vapes online. Even we were surprised at the marketing tactics we found</a>
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<h2>How about labelling?</h2>
<p>This leads to another reason why it’s impossible to tell what is in vapes – the lack of information, including warnings, <a href="https://www.legislation.gov.au/Details/F2021L00595">on the label</a>.</p>
<p>Even if labels are present, they don’t always reflect what’s in the product. Nicotine concentration of e-liquids is often quite different to what is on the label, and “nicotine-free” e-liquids often <a href="https://journal.chestnet.org/article/S0012-3692(20)30134-3/fulltext">contain nicotine</a>.</p>
<p>Products are also labelled with generic flavour names such as “berry” or “tobacco”. But there is no way for a user to know what chemicals have been added to make those “berry” or “tobacco” flavours or the changes in these chemicals that may occur with heating and/or interacting with other ingredients and the device components. “Berry” <a href="https://tobaccocontrol.bmj.com/content/30/2/185">flavour</a> alone could be made from <a href="https://tobaccocontrol.bmj.com/content/tobaccocontrol/suppl/2020/02/10/tobaccocontrol-2019-055447.DC1/tobaccocontrol-2019-055447supp001_data_supplement.pdf">more than 35</a> different chemicals. </p>
<p>Flavouring chemicals may be “food grade” or classified as safe-to-eat. However mixing them into e-liquids, heating and inhaling them is a very different type of exposure, compared to eating them.</p>
<p>One example is benzaldehyde (an almond flavouring). When this is inhaled, it <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.9b00171">impairs</a> the <a href="https://www.sciencedirect.com/science/article/pii/S2214750023000380">immune function</a> of lung cells. This could potentially reduce a vaper’s ability to deal with other inhaled toxins, or respiratory infections. </p>
<p>Benzaldehyde is one of only <a href="https://www.legislation.gov.au/Details/F2021L00595">eight</a> banned e-liquid ingredients in Australia. The list is so short because we don’t have enough information on the health effects if inhaled of other flavouring chemicals, and their interactions with other e-liquid ingredients.</p>
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<h2>Where to next?</h2>
<p>For us to better assess the health risks of vapes, we need to learn more about:</p>
<ul>
<li><p>what happens when flavour chemicals are heated and inhaled</p></li>
<li><p>the interactions between different e-liquid ingredients</p></li>
<li><p>what other contaminants may be present in e-liquids</p></li>
<li><p>new, potentially harmful, substances in e-cigarettes.</p></li>
</ul>
<p>Finally, we need to know more about how people use e-cigarettes so we can better understand and quantify the health risks in the real world.</p><img src="https://counter.theconversation.com/content/210462/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Larcombe has previously received funding for e-cigarette research from the National Health and Medical Research Council, Lung Foundation Australia, Minderoo Foundation, Health Department of Western Australia and Asthma Foundation of Western Australia. The funders played no role in the conduct of the research. He is also a member of the Australian Council on Smoking and Health (ACOSH).</span></em></p>It’s not just the ingredients we should be concerned about. The devices themselves release chemicals that end up in our blood and urine.Alexander Larcombe, Associate Professor and Head of Respiratory Environmental Health, Telethon Kids InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2099572023-07-21T12:26:43Z2023-07-21T12:26:43ZWHO expert cancer group states that the sweetener aspartame is a possible carcinogen, but evidence is limited – 6 questions answered<figure><img src="https://images.theconversation.com/files/538137/original/file-20230718-27-wh515o.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3866%2C2590&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Research on possible links between aspartame consumption and cancer is ongoing and far from conclusive.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/coffee-royalty-free-image/95061040?phrase=artificial%2Bsweetener">celsopupo/iStock via Getty Images Plus</a></span></figcaption></figure><p><em>The World Health Organization declared on July 14, 2023, that the widely used synthetic sweetener <a href="https://www.who.int/news/item/14-07-2023-aspartame-hazard-and-risk-assessment-results-released">aspartame could be a “possible” carcinogen</a>, or cancer-causing agent, on the basis of “limited evidence for cancer in humans.”</em> </p>
<p><em>But the agency also concluded that the currently available data does not warrant a change of the acceptable daily intake of aspartame at this time.</em></p>
<p><em>The Conversation asked chronic disease epidemiologist <a href="http://gsm.utmck.edu/internalmed/faculty/terry.cfm">Paul D. Terry</a>, public health scholar <a href="https://publichealth.utk.edu/people/jchen/">Jiangang Chen</a> and nutrition expert <a href="https://nutrition.utk.edu/people/ling-zhao/">Ling Zhao</a>, all from the University of Tennessee, to put these seemingly contradictory findings into perspective based on the available scientific evidence.</em></p>
<h2>1. Why is aspartame being classified as ‘possibly’ cancer-causing?</h2>
<p>Aspartame is an artificial sweetener that is added to many foods, candies, gums and beverages, such as diet soda. Because it is approximately <a href="https://www.fda.gov/food/food-additives-petitions/aspartame-and-other-sweeteners-food">200 times sweeter than table sugar</a>, smaller amounts of aspartame are added to foods, and they contribute considerably fewer calories. NutraSweet and Equal are well-known brand names for aspartame sold in packages for individual use. </p>
<p>The <a href="https://www.iarc.who.int/cards_page/about-iarc/">International Agency for Research on Cancer</a>, an entity within the WHO, evaluated findings from both human and animal studies of aspartame and cancer. The group noted some positive associations between <a href="https://www.who.int/news/item/14-07-2023-aspartame-hazard-and-risk-assessment-results-released">aspartame consumption and hepatocellular carcinoma</a>, a form of liver cancer. </p>
<p>This WHO group classifies degrees of evidence that an agent has cancer-causing potential as being “sufficient,” “limited,” “inadequate” or “suggesting lack of carcinogenicity.” “Limited” evidence, as it pertains to the WHO’s new announcement on aspartame, means that although there is some evidence for an association, that evidence cannot be considered “sufficient” to infer a causal relationship.</p>
<p>Ultimately, the group concluded that several limiting factors could possibly explain the positive associations in those studies. These include the small number of human studies available, the complexity of studying people’s dietary behaviors and possible bias from factors such as higher-risk people – for example, those with diabetes – selecting diet products more often and ingesting higher quantities of aspartame than the average consumer. Therefore, the classification of “limited evidence” implies the need for additional studies.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/fFvzK-x02Mw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Aspartame is found in many products: diet soda, ice cream, cereals, toothpaste and even some medications.</span></figcaption>
</figure>
<h2>2. What are the current guidelines for aspartame consumption?</h2>
<p>The Food and Agriculture Organization’s <a href="https://www.fao.org/food-safety/scientific-advice/jecfa/en/#">Joint Expert Committee on Food Additives</a>, an international committee of science experts that is operated by both the WHO and the United Nations, currently <a href="https://www.who.int/news/item/14-07-2023-aspartame-hazard-and-risk-assessment-results-released#">recommends a daily maximum</a> of 40 milligrams per kilogram of body weight for aspartame.</p>
<p>This amount of aspartame per day translates to approximately eight to 12 cans of soda, or approximately 60 packets of aspartame, for a person weighing 132 pounds (60 kilograms). For a child weighing 33 pounds (15 kg), it translates to between two to three cans of aspartame-sweetened soda per day, or approximately 15 packets of aspartame. Some individuals may consume more aspartame than this, but such high intake is not typical. </p>
<h2>3. Does the WHO’s new stance change that recommendation?</h2>
<p>Independently of the expert panel on cancer, the food safety group also evaluated the available evidence and concluded that there was no “convincing evidence” from either animal or human studies that aspartame consumption causes adverse effects within the currently established daily limits. </p>
<p>Based on assessments of the findings of both groups, the director of the Department of Nutrition and Food Safety of the WHO stated that, “while safety is not a major concern” at the doses in which aspartame are commonly used, “potential effects have been described that need to be investigated by more and better studies.” The American Cancer Society has also stated that it <a href="https://www.cancer.org/cancer/risk-prevention/chemicals/aspartame.html">supports further research into possible health concerns</a> related to aspartame.</p>
<p>It is important to note that people with the rare inherited disorder called <a href="https://my.clevelandclinic.org/health/diseases/17816-phenylketonuria">phenylketonuria</a>, or PKU, should <a href="https://www.fda.gov/food/food-additives-petitions/aspartame-and-other-sweeteners-food">avoid or restrict aspartame intake</a>. </p>
<h2>4. How can two consensus groups reach different conclusions?</h2>
<p>It is not uncommon for scientific consensus groups to differ in how they classify risk based on the results of published studies, even if more than one of those consensus groups is affiliated with the same agency or parent organization. </p>
<p>Whereas the WHO’s expert cancer group’s stance may appear to be more worrisome than that of the committee on food safety, in fact, the latter’s “no convincing evidence” is consistent with the cancer group’s “limited evidence” classification. Because, unlike the cancer group, the food safety committee considers risk of aspartame at specific consumption levels, the WHO as a whole continues to support the food safety committee’s existing recommendations for allowable daily aspartame intake of up to 40 milligrams per kilogram of body weight. </p>
<p>Of note, the committee’s recommended maximum daily intake is still more conservative than the current U.S. Food and Drug Administration’s <a href="https://www.cancer.org/cancer/risk-prevention/chemicals/aspartame.html">recommended maximum daily allowance</a> of 50 milligrams of aspartame per kilogram of body weight.</p>
<h2>5. How does aspartame compare to other sweeteners?</h2>
<p>Alternatives to aspartame include other <a href="https://theconversation.com/whats-the-difference-between-sugar-other-natural-sweeteners-and-artificial-sweeteners-a-food-chemist-explains-sweet-science-172571">artificial sweeteners</a> such as saccharin and sucralose, sugar alcohols like sorbitol and xylitol, naturally derived sugar-free sweeteners like Stevia and simple sugars, such as those in sugar cane, sugar beets and honey. </p>
<p>But, like aspartame, many of these sweeteners have been implicated in developing cancer. This list includes <a href="https://doi.org/10.1371/journal.pmed.1003950">acesulfame potassium, or Ace-K</a> – a synthetic calorie-free sugar substitute – as well as <a href="https://www.upstate.edu/news/articles/2023/2023-03-25-perl.php">sugar alcohols</a> and even <a href="https://doi.org/10.3390%2Fcancers14246042">simple sugar</a>. </p>
<p>The availability of a wide variety of approved sweeteners seems like a good thing, but studying the many possible risks associated with sweeteners is challenging, since <a href="https://www.science.org/content/blog-post/sugar-substitutes-surprise">people have complex diets and lifestyles</a>. </p>
<h2>6. So what should consumers do?</h2>
<p>For now, as is the case with aspartame, these sweeteners remain approved for human use because there isn’t sufficient evidence to support an association with cancer. And, <a href="https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/artificial-sweeteners/art-20046936">as noted by the Mayo Clinic</a>, artificial sweeteners may play a beneficial role for some people who are <a href="https://doi.org/10.1016/j.eprac.2021.06.013">seeking to manage their weight</a> or control their sugar intake. Studies show that sugar <a href="https://doi.org/10.1136/bjsports-2017-097971">may be addictive for some individuals</a>.</p>
<p>When making a decision about consumption of sweeteners, consumers should consider factors like taste preference, body weight and composition, diabetes status and risk, possible allergic responses and the evidence that may result from ongoing and future studies. In certain cases, such as with individuals who have or are at future risk of diabetes, people should talk with their physician or other health care provider to determine the best choice. </p>
<p>One thing is clear: Scientific studies on aspartame consumption will continue, and it will be important for both consumers and the research community to continue weighing potential risks.</p><img src="https://counter.theconversation.com/content/209957/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An expert panel found a potential association with liver cancer, but too little research exists to assume a causal connection. For now, the WHO left current consumption guidelines unchanged.Paul D. Terry, Professor of Epidemiology, University of TennesseeJiangang Chen, Associate Professor of Public Health, University of TennesseeLing Zhao, Professor of Nutrition, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2088442023-07-14T01:24:43Z2023-07-14T01:24:43ZDoes artificial sweetener aspartame really cause cancer? What the WHO listing means for your diet soft drink habit<figure><img src="https://images.theconversation.com/files/536737/original/file-20230711-23-sl30n6.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C3240%2C2155&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The International Agency for Research on Cancer (IARC), which is the specialised cancer agency of the World Health Organization, has declared aspartame may be a <a href="https://www.who.int/news/item/14-07-2023-aspartame-hazard-and-risk-assessment-results-released">possible carcinogenic hazard to humans</a>. </p>
<p>Another branch of the WHO, the Joint WHO and Food and Agriculture Organization’s Expert Committee on Food Additives has assessed the risk and developed recommendations on how much aspartame is safe to consume. They have recommended the acceptable daily intake be 0 to 40mg per kilo of body weight, as we currently have <a href="https://www.foodstandards.gov.au/consumer/additives/aspartame/Pages/default.aspx">in Australia</a>.</p>
<p>A hazard is different to a risk. The hazard rating means it’s an agent that is capable of causing cancer; a risk measures the likelihood it could cause cancer.</p>
<p>So what does this hazard assessment mean for you?</p>
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<h2>Firstly, what is aspartame?</h2>
<p><a href="https://www.foodstandards.gov.au/consumer/additives/aspartame/Pages/default.aspx">Aspartame is an artificial sweetener</a> that is 200 times sweeter than sugar, but without any kilojoules. </p>
<p>It’s used in a <a href="https://www.foodstandards.gov.au/consumer/additives/aspartame/Pages/default.aspx">variety of products</a> including carbonated drinks such as Coke Zero, Diet Coke, Pepsi Max and some home brand offerings. You can identify aspartame in drinks and foods by looking for additive number 951. </p>
<p>Food products such as yogurt and confectionery may also contain aspartame, but it’s not stable at warm temperatures and thus not used in baked goods. </p>
<p>Commercial names of aspartame include Equal, Nutrasweet, Canderel and Sugar Twin. In Australia the acceptable daily intake is 40mg per kilo of body weight per day, which is about 60 sachets.</p>
<p><a href="https://www.fda.gov/food/food-additives-petitions/aspartame-and-other-sweeteners-food#:%7E:text=How%20many%20packets%20can%20a,based%20on%20its%20sweetness%20intensity%3F&text=Notes%20About%20the%20Chart%3A,50%20mg%2Fkg%20bw%2Fd">In America</a> the acceptable daily intake has been set at 75 sachets. </p>
<h2>What evidence have they used to come to this conclusion?</h2>
<p><a href="https://www.who.int/news/item/14-07-2023-aspartame-hazard-and-risk-assessment-results-released">IARC looked closely</a> at the <a href="https://cdn.who.int/media/docs/default-source/nutrition-and-food-safety/july-13-final-summary-of-findings-aspartame.pdf?sfvrsn=a531e2c1_5&download=true">evidence base</a> from around the world – using data from observational studies, experimental studies and animal studies. </p>
<p>They found there was some limited evidence in human studies linking aspartame and cancer (specifically liver cancer) and limited evidence from animal studies as well. </p>
<p>They also considered the biological mechanism studies which showed how cancer may develop from the consumption of aspartame. Usually these are lab-based studies which show exactly how exposure to the agent may lead to a cancer. In this case they found there was limited evidence for how aspartame might cause cancer.</p>
<p>There were only three human studies that looked at cancer and aspartame intake. These large observational studies used the intake of soft drinks as an indicator of aspartame intake. </p>
<p>All three found a positive association between artificially sweetened beverages and liver cancer in either all of the population they were studying or sub-groups within them. But these studies could not rule out other factors that may have been responsible for the findings. </p>
<p>A study <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6284800/">conducted in Europe</a> followed 475,000 people for 11 years and found that each additional serve of diet soft drink consumed per week was linked to a 6% increased risk of liver cancer. However the scientists did conclude that due to the rarity of liver cancer they still had small numbers of people in the study.</p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/35728406/">In a study from the US</a>, increased risk of liver cancer was seen in people with diabetes who drank more than two or more cans of a diet soda a week.</p>
<p>The <a href="https://aacrjournals.org/cebp/article/31/10/1907/709398/Sugar-and-Artificially-Sweetened-Beverages-and">third study</a>, also from the US, found an increase in liver cancer risk in men who never smoked and drank two or more artificially sweetened drinks a day. </p>
<p>From this they have decided to declare aspartame as a Group 2b “possible carcinogen”. But they have also said more and better research is needed to further understand the relationship between aspartame and cancer. </p>
<p>IARC has four categories (groupings) available for potential substances (or as they are referred to by IARC, “agents”) that may cause cancer.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/536738/original/file-20230711-26-ln4ks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Cup of frothy soda" src="https://images.theconversation.com/files/536738/original/file-20230711-26-ln4ks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536738/original/file-20230711-26-ln4ks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536738/original/file-20230711-26-ln4ks.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536738/original/file-20230711-26-ln4ks.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536738/original/file-20230711-26-ln4ks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536738/original/file-20230711-26-ln4ks.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536738/original/file-20230711-26-ln4ks.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An Australian would have to consume unrealistic amounts of aspartame to reach the daily limit.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What does each grouping mean?</h2>
<p><strong>Group 1 Carcinogenic to humans:</strong> an agent in this group is carcinogenic, which means there is convincing evidence from human studies and we know precisely <em>how</em> it causes cancer. There are 126 agents in this group, including tobacco smoking, alcohol, processed meat, radiation and ionising radiation.</p>
<p><strong>Group 2a Probably carcinogenic to humans:</strong> there are positive associations between the agent and cancer in humans, but there may still be other explanations for the association which were not fully examined in the studies. There are 95 agents in this group, including red meat, DDT insecticide and night shift work.</p>
<p><strong>Group 2b Possibly carcinogenic in humans:</strong> this means limited evidence of causing cancer in humans, but sufficient evidence from animal studies, or the mechanism of how the agent may be carcinogenic is well understood. This basically means the current evidence indicates an agent may possibly be carcinogenic, but more scientific evidence from better conducted studies is needed. There are now <a href="https://monographs.iarc.who.int/agents-classified-by-the-iarc/">323</a> agents in this group, including aloe vera (whole leaf extract), ginkgo biloba and lead.</p>
<p><strong>Group 3 Not classifiable as a carcinogen:</strong> there’s not enough evidence from humans or animals, and there is limited mechanistic evidence of how it may be a carcinogen. There are 500 agents in this group.</p>
<h2>So do I have to give up my diet soft drink habit?</h2>
<p>For a 70kg person you would need to consume about 14 cans (over 5 litres) of soft drink sweetened with aspartame a day to reach the acceptable daily intake.</p>
<p>But we need to remember there may also be aspartame added in other foods consumed. So this is an unrealistic amount to consume, but not impossible. </p>
<p>We also need to consider all the evidence on aspartame together. The foods we typically see aspartame in are processed or ultra-processed, which have recently also been <a href="https://theconversation.com/ultra-processed-foods-are-trashing-our-health-and-the-planet-180115">shown to be detrimental to health</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ultra-processed-foods-are-trashing-our-health-and-the-planet-180115">Ultra-processed foods are trashing our health – and the planet</a>
</strong>
</em>
</p>
<hr>
<p>And artificial sweeteners (including aspartame) <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892765/#!po=59.3750">can make people crave more sugar</a>, making them want to eat more food, potentially causing them to gain more weight.</p>
<p>All together, this indicates we should be more careful about the amount of artificial sweeteners we consume, since they <a href="https://theconversation.com/the-who-says-we-shouldnt-bother-with-artificial-sweeteners-for-weight-loss-or-health-is-sugar-better-205827">do not provide any health benefits</a>, and have possible adverse effects. </p>
<p>But overall, from this evidence, drinking the occasional or even daily can of a diet drink is safe and probably not a cancer risk.</p>
<hr>
<p><em>Correction: this article originally stated each serve of soft drink in a study was linked to a 6% increased risk of liver cancer, however it was each additional serve per week. This has been amended.</em></p><img src="https://counter.theconversation.com/content/208844/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Evangeline Mantzioris is affiliated with Alliance for Research in Nutrition, Exercise and Activity (ARENA) at the University of South Australia. Evangeline Mantzioris has received funding from the National Health and Medical Research Council, and has been appointed to the National Health and Medical Research Council Dietary Guideline Expert Committee.</span></em></p>IARC has listed the artificial sweetener aspartame as possibly cancer causing. Here’s how to digest the findings.Evangeline Mantzioris, Program Director of Nutrition and Food Sciences, Accredited Practising Dietitian, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2088952023-07-04T15:11:40Z2023-07-04T15:11:40ZAspartame: popular sweetener could be classified as a possible carcinogen by WHO – but there’s no cause for panic<figure><img src="https://images.theconversation.com/files/535489/original/file-20230704-16-qfev1h.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5646%2C3764&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/double-cool-ice-soft-drink-cola-647315608">MMD Creative/Shutterstock</a></span></figcaption></figure><p>According to <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/whos-cancer-research-agency-say-aspartame-sweetener-possible-carcinogen-sources-2023-06-29/">reports</a>, the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), is set to declare the artificial sweetener aspartame as “possibly carcinogenic to humans”. </p>
<hr>
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<p><em>You can listen to more articles from The Conversation, narrated by Noa, <a href="https://theconversation.com/us/topics/audio-narrated-99682">here</a>.</em></p>
<hr>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/26377607/">Aspartame</a> is about <a href="https://www.sciencedirect.com/science/article/abs/pii/0308814685901190">200 times sweeter</a> than sugar and is one of the most commonly used artificial sweeteners. It’s used particularly in “low calorie” or “diet” foods and beverages, but is contained in a wide variety of products including drinks, ice creams, chewing gums, confectionery, sauces and snacks.</p>
<p>We don’t have further information yet on what evidence the IARC will base this new classification on, but the WHO will publish the full data <a href="https://monographs.iarc.who.int/wp-content/uploads/2023/06/Meeting134-QA-June2023.pdf">on July 14</a>. </p>
<p>While reports like these can understandably be worrying, there’s no reason to panic at this stage.</p>
<p>Aspartame was first approved for use by the US Food and Drug Administration (FDA) <a href="https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2013.3496">in 1974</a>, and ever since then there have been claims made about its potential effects on health. </p>
<p>Over time, aspartame has not only been linked to cancer, but also to <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0116212">other conditions</a> such as multiple sclerosis, blindness, seizures, memory loss, depression, anxiety, birth defects and death. </p>
<p>However, frequent evaluations by regulatory agencies such as the <a href="https://apps.who.int/food-additives-contaminants-jecfa-database/Home/Chemical/62">WHO</a>, the FDA and the <a href="https://www.efsa.europa.eu/en/efsajournal/pub/3496">European Food Safety Authority</a> (EFSA) have found no evidence to support these assertions.</p>
<p>So far, the regulators have all agreed that it’s safe for a person to consume <a href="https://www.efsa.europa.eu/en/efsajournal/pub/3496">40mg of aspartame</a> per kilogram of their body weight per day. That’s about 2.8g for a 70kg adult – and is much more than most people consume. </p>
<h2>What does ‘possibly carcinogenic’ actually mean?</h2>
<p>The safety of food additives is <a href="https://www.efsa.europa.eu/en/topics/topic/food-additive-re-evaluations">regularly reevaluated</a>. This is important as new evidence can emerge, especially with the development of different methods to assess the health effects of additives.</p>
<p>This year, aspartame has been reevaluated by two WHO agencies: the International Agency for Research on Cancer (<a href="https://www.iarc.who.int/">IARC</a>) and the Joint FAO/WHO Expert Committee on Food Additives (<a href="https://www.who.int/groups/joint-fao-who-expert-committee-on-food-additives-(jecfa)">JECFA</a>). </p>
<p>The two agencies have <a href="https://monographs.iarc.who.int/wp-content/uploads/2023/06/Meeting134-QA-June2023.pdf">very different remits</a>. The IARC looks at hazard and JECFA at risk. This distinction is important. For example, sunshine is a hazard as it can cause skin cancer, but the risk depends on the time spent in the sun and whether one uses sunscreen.</p>
<p>The IARC’s job is to investigate possible causes of cancer and identify hazards. In its <a href="https://monographs.iarc.who.int/">reports</a> (called monographs), it reviews all available evidence and classifies hazards into one of <a href="https://www.iarc.who.int/wp-content/uploads/2023/06/IARC_MONO_classification_2023_updated.png">four categories</a>: </p>
<ul>
<li>Group 1: carcinogenic to humans (sufficient evidence for cancer in humans)</li>
<li>Group 2a: probably carcinogenic to humans (limited evidence in humans, sufficient evidence in animals)</li>
<li>Group 2b: possibly carcinogenic to humans (limited evidence in humans, insufficient evidence in animals) </li>
<li>Group 3: not classifiable (inadequate evidence in humans or animals).</li>
</ul>
<p>Aspartame will reportedly be classified into group 2b. It shares this category with aloe vera leaves, electromagnetic radiation, the heart drug <a href="https://bnf.nice.org.uk/drugs/digoxin/">digoxin</a> and engine exhaust fumes, among <a href="https://www.bbc.com/future/article/20230630-aspartame-what-else-is-possibly-cancerous">many other things</a>. For all of these hazards, there is some limited data that suggests they might cause cancer – but nothing convincing. </p>
<p>These categories can be confusing, because they refer only to the strength of the evidence that something can cause cancer, not the degree of risk. Group 1 for example includes smoking, alcohol, <a href="https://theconversation.com/not-all-processed-meats-carry-the-same-cancer-risk-64622">processed meat</a>, plutonium and sunlight. There’s convincing evidence each one can cause cancer. </p>
<p>But the actual risks are very different and depend on amount and exposure. For instance, plutonium and smoking are best avoided, but there’s no reason to avoid processed meat or alcohol completely.</p>
<figure class="align-center ">
<img alt="A hand holds a cigarette." src="https://images.theconversation.com/files/535511/original/file-20230704-29-7padyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/535511/original/file-20230704-29-7padyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/535511/original/file-20230704-29-7padyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/535511/original/file-20230704-29-7padyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/535511/original/file-20230704-29-7padyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/535511/original/file-20230704-29-7padyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/535511/original/file-20230704-29-7padyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Smoking is known to cause cancer.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/harmful-habit-hand-holding-cigarette-smoke-1885761310">Oakland Images/Shutterstock</a></span>
</figcaption>
</figure>
<p>While the IARC assesses the hazard, it’s JECFA’s job to assess the risk and make a recommendation about the <a href="https://apps.who.int/iris/bitstream/handle/10665/37578/9241542705-eng.pdf">acceptable daily intake</a>. </p>
<p>Their assessment will also be published on July 14, but there hasn’t been an indication in the media reports what it will say. It’s possible the acceptable daily intake will remain at 40mg per kilogram of body weight, or it may be reduced. Without having access to the data, is impossible to predict. </p>
<h2>The evidence so far</h2>
<p>The last review of aspartame’s safety was <a href="https://www.efsa.europa.eu/en/press/news/131210">conducted by EFSA</a> in 2013. This review didn’t find any new evidence that aspartame causes cancer and confirmed previous reviews by other regulators.</p>
<p>One compound that was of particular interest was <a href="https://www.efsa.europa.eu/en/efsajournal/pub/3496">methanol</a>, which is formed in the gut when aspartame is broken down and converted into formaldehyde by the human body. Formaldehyde is a known carcinogen (group 1). However, the amount that can form after the consumption of aspartame is much lower than what the body produces naturally.</p>
<p>In the interim there has been some data from a French study, which asked participants to provide information about their diet and followed them up for several years afterwards. This research suggested high consumption of aspartame <a href="https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003950">increases cancer risk</a>.</p>
<p>However, the results are difficult to interpret as obesity is <a href="https://www.wcrf.org/diet-activity-and-cancer/risk-factors/obesity-weight-gain-and-cancer">an independent risk factor</a> for cancer and people who are obese often use sweeteners. It’s also difficult to estimate aspartame intake accurately <a href="https://theconversation.com/a-whole-new-way-of-doing-nutrition-research-148352">from diet data alone</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/artificial-sweeteners-linked-to-diabetes-and-obesity-95314">Artificial sweeteners linked to diabetes and obesity</a>
</strong>
</em>
</p>
<hr>
<p>It’s likely that the upcoming assessments will include this data and therefore provide a better estimate of aspartame’s risk. Until then, there is no reason for concern. Aspartame has been scrutinised for a long time and the classification of “possibly carcinogenic” suggests it’s unlikely there will be any major change in assessment or implications for consumers.</p><img src="https://counter.theconversation.com/content/208895/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gunter Kuhnle has received research funding from Mars, Inc.</span></em></p>Reports have indicated the artificial sweetener aspartame will be classified as ‘possibly carcinogenic to humans’ by the WHO. Here’s what that means – and doesn’t mean.Gunter Kuhnle, Professor of Nutrition and Food Science, University of ReadingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1934312023-01-30T13:12:57Z2023-01-30T13:12:57ZDoes this cause cancer? How scientists determine whether a chemical is carcinogenic – sometimes with controversial results<figure><img src="https://images.theconversation.com/files/506177/original/file-20230124-18-m5hdd.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3000%2C1500&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Carcinogenic chemicals are labeled with a health hazard warning symbol. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/serious-health-hazard-royalty-free-illustration/1353836395">Peter Etchells/iStock via Getty Images Plus</a></span></figcaption></figure><p>People are <a href="https://www.universityofcalifornia.edu/news/toxic-exposure-chemicals-are-our-water-food-air-and-furniture">exposed to numerous chemicals</a> throughout their lifetimes. These chemicals can be from the air, foods, personal care items, household products and medications. Unfortunately, exposure to certain chemicals can cause harmful health effects, including cancer. Substances that cause cancer are called <a href="https://www.genome.gov/genetics-glossary/Carcinogen">carcinogens</a>. Familiar examples include <a href="https://monographs.iarc.who.int/wp-content/uploads/2018/06/mono100E-6.pdf">tobacco smoke</a>, <a href="https://monographs.iarc.who.int/wp-content/uploads/2018/06/mono100D-9.pdf">radon</a>, <a href="https://monographs.iarc.who.int/wp-content/uploads/2018/06/mono100C-11.pdf">asbestos</a> and <a href="https://www.iarc.who.int/news-events/iarc-diesel-engine-exhaust-carcinogenic/">diesel engine exhaust</a>.</p>
<p>To protect the health of the public, national and international health agencies evaluate many new and existing chemicals to determine if they are likely to be carcinogens in a process called <a href="https://pubmed.ncbi.nlm.nih.gov/9715519/">cancer hazard identification</a>. If agencies judge the chemicals to be carcinogenic, they conduct further assessments to determine the level of risk, and legislators may put regulations in place to limit, or completely halt, the production and use of these chemicals.</p>
<p><a href="https://www.engr.colostate.edu/cbe/people/brad-reisfeld/">I am a scientist</a> who studies how the human body processes foreign chemicals, like environmental pollutants and drugs, and the effects of these chemicals on health. As part of my work, I have participated in chemical and cancer hazard identifications for several agencies, including the World Health Organization’s <a href="https://www.iarc.who.int">International Agency for Research on Cancer</a>. Here’s how chemicals can cause cancer, and how we classify chemicals based on on how carcinogenic they are – sometimes with controversial results.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person in protective suit spraying herbicide on plants" src="https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Glyphosate, an herbicide used in products like Roundup, was classified by the IARC as probably carcinogenic to humans in 2015.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/person-in-protective-suit-spraying-herbicide-on-royalty-free-image/1327771135">Adriana Duduleanu/EyeEm via Getty Images</a></span>
</figcaption>
</figure>
<h2>How do chemicals cause cancer?</h2>
<p>The mechanisms behind how toxic chemicals can lead to cancer <a href="https://www.ncbi.nlm.nih.gov/books/NBK570326/">are complex</a>. </p>
<p>After a person is exposed to a carcinogen, the chemical is generally absorbed into the body and distributed into different tissues. Once the chemical has moved into the cells, it often undergoes chemical reactions that convert it into other forms. </p>
<p>The products of these reactions can directly or indirectly affect the cell’s genes. Altering genes, which contain the cell’s instructions on how to produce specific molecules, or the processes that regulate them can ultimately result in dysfunctional cells if the genetic damage isn’t repaired. These cells don’t respond normally to cellular signals and can grow and divide at abnormal rates, which are characteristic features of cancer cells.</p>
<h2>How are chemicals classified for carcinogenicity?</h2>
<p>To help safeguard the public and reduce the incidence of cancer, several agencies have developed procedures to classify and categorize chemicals based on their potential to be carcinogenic. </p>
<p><a href="https://www.atsdr.cdc.gov/pha-guidance/conducting_scientific_evaluations/indepth_toxicological_analysis/EvaluateEvidenceCancerEffects.html">Among them</a> are the International Agency for Research on Cancer, or IARC Monographs; the National Toxicology Program, or NTP; and the U.S. Environmental Protection Agency, or EPA. In general, these agencies examine a critical question: How strong is the evidence that a substance causes cancer or biological changes that could be related to cancer in people? Understanding the procedures used to answer this question can help with interpreting the decisions these agencies make.</p>
<p>The <a href="https://monographs.iarc.who.int/iarc-monographs-preamble-preamble-to-the-iarc-monographs/">procedures used by the IARC</a> – because of its long history, credibility and strong international reputation – provide a good example of how this process works. It’s designed to be transparent and minimize bias, spanning over a year from selecting a chemical for evaluation to its final classification. </p>
<p>In this process, the IARC selects and invites a panel of scientific experts on the chemical to be evaluated. The panel does not conduct new research on its own, but carefully reviews all available papers in the scientific literature on the chemical’s carcinogenicity in cell and bacterial cultures, animals and people. To assess the strength of the evidence, the panel carefully considers the number of studies that are available and the consistency of the results, as well as the scientific quality and relevance of each study to cancer in people.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/R_MLl3O4dKo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Chemicals can be carcinogenic to varying degrees.</span></figcaption>
</figure>
<p>After discussing and deliberating on the results, the panel makes a final consensus classification. This classification places the chemical into one of four groups: Group 1 indicates that the chemical is carcinogenic to people, Group 2A that it is probably carcinogenic to people, Group 2B that it is possibly carcinogenic to people, and Group 3 that it is not classifiable. A Group 3 classification does not indicate that the compound is not carcinogenic, but rather that the panel could not draw a conclusion about whether there is a causal link between the chemical and cancer from available studies. For example, exposure to several chemicals can make it unclear which ones are responsible for a later cancer diagnosis.</p>
<p>During its 50-year history, the IARC has evaluated and classified <a href="https://monographs.iarc.who.int/wp-content/uploads/2018/07/cumulative-cross-index.pdf">over 1,000 chemicals and other hazards</a>. Many of these classifications have had broad societal implications, such as those for tobacco smoke, ambient air pollution, diesel engine exhaust and processed meat. All were classified as Group 1, or confirmed to be carcinogenic to humans. <a href="https://www.iarc.who.int/pressrelease/iarc-classifies-radiofrequency-electromagnetic-fields-as-possibly-carcinogenic-to-humans/">Electromagnetic radiation</a> emitted by mobile phones was classified as Group 2B, or possibly carcinogenic, and <a href="https://www.iarc.who.int/featured-news/media-centre-iarc-news-redmeat/">red meat</a> was classified as Group 2A, or probably carcinogenic. Though they haven’t directly led to any regulations, these classifications have motivated <a href="https://doi.org/10.3389/fpubh.2019.00223">additional</a> <a href="https://doi.org/10.1007/s13668-021-00377-x">scientific studies</a>. While the IARC can advise regulators, it’s up to countries to implement policies.</p>
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<p>It is important to note that classifications do not indicate the size of the risk but are important in supporting health agencies worldwide as they implement actions to limit exposures to known, probable and possible carcinogens. In 2020, when the IARC <a href="https://www.iarc.who.int/news-events/iarc-monographs-evaluation-of-the-carcinogenicity-of-opium-consumption/">classified opium consumption as Group 1</a>, or carcinogenic to humans, this led the government of Iran to <a href="https://www.youtube.com/watch?v=hJDlJhtPeiQ">implement policies</a> to reduce opium addiction in the country.</p>
<h2>Controversies in carcinogenicity classifications</h2>
<p>Though classifications from the IARC are based on robust scientific evidence, some have <a href="https://doi.org/10.1093/carcin/bgv062">proved to be controversial</a>. </p>
<p>For instance, in 2015, the IARC evaluated the carcinogenicity of <a href="https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/Some-Organophosphate-Insecticides-And-Herbicides-2017">glyphosate</a>, a widely used weedkiller found in products like Roundup, which is produced by Monsanto. A panel of 17 experts from 11 countries systematically reviewed results from over 1,000 scientific studies and classified glyphosate as “probably carcinogenic to humans,” or Group 2A.</p>
<p>Owing to its widespread usage and <a href="https://www.transparencymarketresearch.com/glyphosate-market.html">multibillion-dollar market value</a>, a cancer classification decision for glyphosate has significant potential financial and legal consequences. Following its evaluation, the IARC received support from many <a href="https://oehha.ca.gov/proposition-65/general-info/oehha-statement-regarding-us-epas-press-release-and-registrant-letter">regulatory</a> and <a href="https://www.env-health.org/campaigns/glyphosate-why-the-eu-needs-to-protect-health-ban-the-popular-weedkiller/">scientific bodies</a> but was <a href="https://www.science.org/content/article/who-rebuts-house-committee-criticisms-about-glyphosate-cancer-warning">criticized by others</a>. Other agencies, <a href="https://www.gao.gov/products/gao-19-280">including</a> <a href="https://www.epa.gov/office-inspector-general/report-epa-needs-improve-transparency-its-cancer-assessment-process">the EPA</a>, have seen similar controversies and politicization of their hazard identifications and regulatory decisions.</p>
<p>I believe that agencies like the IARC play a critical role in evaluating the health effects of certain chemicals and in reducing exposure to potential carcinogens. Helping people better understand how these agencies evaluate chemicals can go a long way to ensure transparency and help protect environmental and public health.</p><img src="https://counter.theconversation.com/content/193431/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brad Reisfeld does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The WHO’s International Agency for Research on Cancer convenes a panel of scientific experts to review available evidence on whether specific chemicals or occupational exposures may cause cancer.Brad Reisfeld, Professor of Chemical and Biological Engineering, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1890512022-09-06T00:14:15Z2022-09-06T00:14:15ZMicroplastics are common in homes across 29 countries. New research shows who’s most at risk<figure><img src="https://images.theconversation.com/files/481984/original/file-20220831-22-kajqnp.jpg?ixlib=rb-1.1.0&rect=0%2C1727%2C3808%2C2510&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Pexels</span></span></figcaption></figure><p>The evidence is clear: microplastics have contaminated <a href="https://www.nature.com/articles/d41586-021-01143-3">every corner of the globe</a>. We can’t escape exposure to these tiny bits of plastic (less than 5mm across) in the environment, which includes the homes where people <a href="https://www.nature.com/articles/7500165">spend most of their time</a>. </p>
<p>Recent research has discovered <a href="https://www.sciencedirect.com/science/article/pii/S0160412022001258">microplastics in the blood of humans</a>. However, the question of harm to humans <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7068600/">remains unresolved</a>. Despite concerns that some substances in microplastics could cause cancer or damage our DNA, we still have a poor grasp of the true risks of harm. </p>
<p>Our <a href="https://doi.org/10.1016/j.envpol.2022.119957">study of global microplastics</a> exposure inside homes across 29 countries, published today, shows people living in lower-income countries and young children are at greater risk of exposure. But our analysis of the chemical composition of microplastics in the home shows the specific health risk is surprisingly low. The study covered all the continents, including Australia.</p>
<p>The current challenge in understanding health risks from microplastics is the very limited data on toxic effects of the petrochemicals used in plastics production. </p>
<p>A recurrent theme in the environmental health research literature is that early concerns about suspect chemicals and related compounds, including those found in plastics, <a href="https://ec.europa.eu/environment/chemicals/non-toxic/pdf/NTE%20main%20report%20final.pdf">were eventually justified</a>. The effects of suspect substances only become clear after extensive toxicological and epidemiological research.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/youre-eating-microplastics-in-ways-you-dont-even-realise-97649">You're eating microplastics in ways you don't even realise</a>
</strong>
</em>
</p>
<hr>
<h2>What did the new study look at?</h2>
<p>Our study investigated three main questions relating to exposure to microplastics inside homes:</p>
<ol>
<li><p>what are the impacts in different countries across the world?</p></li>
<li><p>who is most at risk?</p></li>
<li><p>what are the specific health risks?</p></li>
</ol>
<p>We reached out to residents across 29 countries to collect their indoor atmospheric dust over a one-month period. At 108 homes sampled across these countries, we also collected information about households and behaviours. This helped us to better understand possible sources and causes of microplastics in dust. These data included:</p>
<ul>
<li><p>how often floors were cleaned</p></li>
<li><p>flooring type</p></li>
<li><p>presence or absence of children</p></li>
<li><p>number of people living in each home</p></li>
<li><p>percentage of full-time workers.</p></li>
</ul>
<p>In each home, atmospheric dust particles were collected in specially cleaned and prepared glass Petri dishes. We measured the levels of microplastics in the collected dust using a suite of microscopic techniques and instruments. We used <a href="https://www.chem.uci.edu/%7Edmitryf/manuals/Fundamentals/FTIR%20principles.pdf">infrared spectroscopy</a> – which identifies substances by how they interact with light – to determine the chemical composition of these microplastics.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/house-dust-from-35-countries-reveals-our-global-toxic-contaminant-exposure-and-health-risk-172499">House dust from 35 countries reveals our global toxic contaminant exposure and health risk</a>
</strong>
</em>
</p>
<hr>
<h2>What did the study find?</h2>
<p>The household dust contained a wide variety of synthetic <a href="https://www.livescience.com/60682-polymers.html">polymer</a> fibres. The most common were:</p>
<ul>
<li><p>polyester (as polyethylene terephthalate) at 9.1%, which is used in clothing fabrics</p></li>
<li><p>polyamide (7.7%), which is mainly used in textiles</p></li>
<li><p>polyvinyls (5.8%), which are used in floor varnishes</p></li>
<li><p>polyurethane (4.4%), which is used in surface coatings of furniture and in bedding</p></li>
<li><p>polyethylene (3.6%), a common polymer used in food containers and reusable bags. </p></li>
</ul>
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<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/481992/original/file-20220831-1921-rycya7.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/481992/original/file-20220831-1921-rycya7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481992/original/file-20220831-1921-rycya7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1297&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481992/original/file-20220831-1921-rycya7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1297&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481992/original/file-20220831-1921-rycya7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1297&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481992/original/file-20220831-1921-rycya7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1630&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481992/original/file-20220831-1921-rycya7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1630&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481992/original/file-20220831-1921-rycya7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1630&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
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<span class="attribution"><a class="source" href="https://www.sciencedirect.com/science/article/pii/S026974912201171X?via%3Dihub">Author provided, The Conversation</a></span>
</figcaption>
</figure>
<hr>
<p>We examined the prevalence and risk of microplastics according to the gross national income of each country, grouped as low, medium and high-income (such as Australia). Overall, we found lower-income countries have higher loads of microplastics, which were deposited at an average daily rate of 3,518 fibres per square metre. The rates for medium-income and high-income countries were 1,268 and 1,257 fibres/m²/day.</p>
<p>In low-income countries, the most prevalent synthetic polymer fibres were made of polyurethane (11.1% of all fibres in samples). In high-income countries, polyamide and polyester were the most prevalent microplastic types (11.2% and 9.8% respectively). </p>
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<hr>
<h2>So what are the health risks?</h2>
<p>For the first time we could attribute the health risk across countries according to incomes. Our analyses showed lower-income countries are at higher risk from microplastic pollution. This aligns with <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(17)32345-0/fulltext">research findings</a> on other toxic exposures – poorer countries and people are most at risk from pollution. </p>
<p>Nevertheless, we found the overall risk from microplastics exposure was low. We used the US Environmental Protection Agency’s <a href="https://www.epa.gov/iris">toxicity information</a> on polymers in the microplastics to calculate health risk based on the types and levels we detected. </p>
<p>Low-income countries had a higher lifetime risk of cancers due to indoor microplastic exposure at 4.7 people per million. High-income countries were next at 1.9 per million, with medium-income countries at 1.2 per million. </p>
<p>We attributed these differences in cancer risk to the different percentages of carcinogenic substances in the microplastics found in household dust.</p>
<p>We calculated the sum of the carcinogenic risk from inhalation and ingestion of the following chemicals in the microplastic fibres: vinyl chloride (polyvinyl chloride), acrylonitrile (polyacrylics) and propylene oxide (polyurethane). Because toxicity data for polymers are limited, the assessment was a minimum estimate of true risk.</p>
<p>Children are at greater risk irrespective of income, which is true for many types of environmental exposures. This is because of their smaller size and weight, and tendency to have more contact with the floor and to put their hands in their mouths more often than adults.</p>
<p>Our analysis indicated that the microplastics came mainly from sources inside the home, and not from outside. Synthetic polymer-based materials are used widely in high-income countries in products such as carpets, furniture, clothing and food containers. We anticipated levels of microplastic shedding in the home might be greater in these countries. </p>
<p>However, analysis of the data showed the only factor obviously linked with levels of microplastics in deposited dust was how often they were vacuumed. Frequent vacuuming reduces microplastic levels. </p>
<p>Vacuuming was more frequent in higher-income countries. Factors that influence the type of cleaning include people’s preference for sweeping and mopping versus vacuuming, as well as their access to and capacity to afford electronic vacuum cleaners.</p>
<figure class="align-center ">
<img alt="Person vacuuming a rug on a timber floor in the home" src="https://images.theconversation.com/files/482223/original/file-20220901-24-dmslui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482223/original/file-20220901-24-dmslui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482223/original/file-20220901-24-dmslui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482223/original/file-20220901-24-dmslui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482223/original/file-20220901-24-dmslui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482223/original/file-20220901-24-dmslui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482223/original/file-20220901-24-dmslui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The levels of microplastics in the home appear to be reduced by frequent vacuuming.</span>
<span class="attribution"><span class="source">Liliana Drew/Pexels</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/were-all-ingesting-microplastics-at-home-and-these-might-be-toxic-for-our-health-here-are-some-tips-to-reduce-your-risk-159537">We're all ingesting microplastics at home, and these might be toxic for our health. Here are some tips to reduce your risk</a>
</strong>
</em>
</p>
<hr>
<h2>What can we do to reduce the risks?</h2>
<p>Based on this and our previous <a href="https://doi.org/10.1016/j.envpol.2021.117064">study data</a>, it is clear vacuuming regularly, instead of sweeping, is associated with less airborne microplastics indoors. Other obvious actions – such as choosing natural fibres for clothing, carpets and furnishings instead of petrochemical-based polymer fibres – can reduce the shedding of microplastics indoors.</p>
<p>Future research needs to focus on developing more complete profiles of the harmful effects of each of the toxic petrochemical-based synthetic polymers that can produce microplastics. This will give us a better understanding of the risks of exposure to these ubiquitous pollutants.</p><img src="https://counter.theconversation.com/content/189051/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Patrick Taylor received funding via an Australian Government Citizen Science Grant (2017-2020), CSG55984 ‘Citizen insights to the composition and risks of household dust’ (the DustSafe project). The VegeSafe and DustSafe programs are supported by publication donations to Macquarie University. He is a full-time employee of EPA Victoria, appointed to the statutory role of Chief Environmental Scientist.</span></em></p><p class="fine-print"><em><span>Neda Sharifi Soltani works for Macquarie University. She receives funding from Macquarie University. </span></em></p><p class="fine-print"><em><span>Scott P. Wilson has received funding from state and federal grants, corporate entities and philanthropic and charitable organisations to undertake his research . He undertook this work while employed by Macquarie University but is currently employed by Earthwatch Australia. </span></em></p>It’s impossible to escape exposure to microplastics and a new study confirms they’re in household dust around the world. But the health risks appear surprisingly low, and vacuuming makes a difference.Mark Patrick Taylor, Chief Environmental Scientist, EPA Victoria; Honorary Professor, School of Natural Sciences, Macquarie UniversityNeda Sharifi Soltani, Academic Casual, School of Natural Sciences, Macquarie UniversityScott P. Wilson, Chief Scientist, Earthwatch Australia, Honorary Senior Research Fellow, School of Natural Sciences, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1886212022-08-31T16:56:31Z2022-08-31T16:56:31ZWaste pickers in Lagos tell their stories about a dangerous existence<figure><img src="https://images.theconversation.com/files/481014/original/file-20220825-20-y7xgw3.jpg?ixlib=rb-1.1.0&rect=3%2C3%2C2592%2C1677&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Waste pickers at the Olusosan landfill work in a hazardous environment. </span> <span class="attribution"><span class="source">Lionel Healing/AFP</span></span></figcaption></figure><p>Lagos, Nigeria’s economic hub, with a population of more than <a href="https://worldpopulationreview.com/world-cities/lagos-population">15 million</a>, generates an estimated <a href="https://www.scientific.net/JERA.35.11">12,000</a> metric tonnes of waste daily, which comes to about 4.3 million tonnes of waste annually. This ends up on the streets and in the city’s four officially designated landfills.</p>
<p>These sites support thousands of people who search through what’s discarded for materials with resale value. Our <a href="https://www.tandfonline.com/doi/full/10.1080/00207233.2022.2055344">survey</a> of two landfill sites discovered a total of about 2,800 waste pickers – men and women. </p>
<p>Most landfills have buy-back centres, where the waste pickers sell recyclables such as metal, glass, plastic and paper. We observed that the subsistence incomes of waste pickers fluctuated daily, depending on the volume of recyclable waste delivered to the landfill, its quality, and varying prices. The daily average income of the street waste pickers was N2,075 (US$4.99) while that of the landfill waste pickers was N5,530 (US$13.30). Though this average income is higher than the <a href="https://databankfiles.worldbank.org/data/download/poverty/987B9C90-CB9F-4D93-AE8C-750588BF00QA/AM2021/Global_POVEQ_NGA.pdf">poverty line</a>, the work and the environment are hazardous, and its value is not fully appreciated.</p>
<p>Waste pickers often work without protective gear, unassisted, and without access to primary care or first aid and employment regulations. They operate on the margins of or outside the formal process of managing solid waste, but play vital roles, especially in reuse, recycling and cost recovery. </p>
<p>They work in unsheltered environments and are unprotected from severe heat, sun, rain, and cold weather. These conditions have been linked with <a href="https://doi.org/10.1155/2021/5530064">cardiovascular disorders</a>. Likewise, exposure to dust, micro-organisms and microbial toxins can result in chronic respiratory diseases, <a href="https://pubmed.ncbi.nlm.nih.gov/7569875/">skin problems and gastrointestinal illnesses</a>. </p>
<p>Research on waste pickers has tended to focus on the health risks of their occupation. Our <a href="https://www.tandfonline.com/doi/abs/10.1080/00207233.2022.2055344?casa_token=PHnkskfO9ZIAAAAA:Y7PdgyDp5035bdZXV_0zHELhvZbD98vN9WUZGMDThwEHKpZEm0TfZfnQReqgqRZLAh4wM4DDSPeE">study</a> confirmed that Lagos waste pickers were exposed to occupational health hazards, but also aimed to reveal more about their well-being and their own perspectives. </p>
<p>The findings may help waste management authorities to make landfills a more dignified working environment that sustains waste pickers’ livelihoods without jeopardising their well-being.</p>
<h2>Occupational hazards of waste picking</h2>
<p>For our research, we interviewed 125 waste pickers in Olusosun landfill and 27 in Solous landfill. Olusosun is situated in Ojota, Kosofe Local Government Area and Solous in Egbeda, Alimosho Local Government Area of Lagos state.</p>
<p>We established that waste picking in landfills was mostly done by younger people: 88% of our respondents were aged between 18 and 45. The collection of recyclable materials and items was mostly done by men, while the sorting was mostly by women.</p>
<p>They operated at the landfill because of the abundance and concentration of waste there. In fact, 66% lived at the dumpsite. The majority worked seven days a week. The average number of years they had spent doing this work was seven.</p>
<p>Most of the waste pickers we spoke to had experienced illnesses or injuries. Body pain, bruises and fatigue were the most frequently mentioned conditions.
Most waste pickers had bruises or scars on their hands, arms and feet, mainly from cuts or piercings during sorting. </p>
<p>Other illnesses and injuries were caused by inappropriate posture and prolonged work hours. Many had sore or itchy eyes caused by exposure to smoke from burning garbage and to other hazards like methane gas, sulphur dioxide and carbon monoxide.</p>
<p>The people in our study didn’t use personal protective equipment or go for regular medical checks. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/nigerias-plastic-pollution-is-harming-the-environment-steps-to-combat-it-are-overdue-177839">Nigeria's plastic pollution is harming the environment: steps to combat it are overdue</a>
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</em>
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<hr>
<p>When we asked about their subjective feelings, we found that the waste pickers were very dissatisfied with their unhealthy working conditions, the extreme poverty they lived in, and the stigmatisation they experienced. Many used alcohol and drugs. Most said they were distressed by their work. </p>
<p>They experienced discrimination, prejudice and social rejection. </p>
<p>Yet with low education levels – 61% were illiterate – they could not find other work. They settled for waste picking as a last resort to earn a living.</p>
<h2>Value of waste pickers</h2>
<p>Nigerian authorities don’t fully appreciate the <a href="https://www.wiego.org/publications/feminizing-waste-waste-picking-empowerment-opportunity-women-children-impoverished-communities">beneficial role</a> of waste pickers. These workers contribute to environmental sustainability by reducing wastes in dumpsites and providing material for recycling and reuse. But they are never considered when waste management policies are designed.</p>
<p>Waste pickers should be recognised in waste management policies and their well-being should be taken seriously.</p>
<p>Waste management authorities, NGOs and multinational organisations must ensure that potable water, sanitary facilities and clinics are provided at landfills. Waste pickers must be allowed to use them free of charge, as is the case in Brazil.</p>
<p>In addition, waste pickers should be encouraged to develop workplace health frameworks to alleviate accidents and risks. </p>
<p>Training to build their capacity and expand their skills, giving them other work opportunities, could reduce their dissatisfaction. </p>
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<strong>
Read more:
<a href="https://theconversation.com/african-digital-innovators-are-turning-plastic-waste-into-value-but-there-are-gaps-188014">African digital innovators are turning plastic waste into value -- but there are gaps</a>
</strong>
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<p>There is also a need for investment in regular occupational health and safety training through public/private partnerships. Waste pickers should be provided with personal protective equipment and monitored to ensure proper use. Non-compliance should be penalised.</p>
<p>Lastly, the rights of waste pickers must be protected. They should not be stigmatised but treated as essential to waste management.</p><img src="https://counter.theconversation.com/content/188621/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Olanrewaju Dada does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Lagos waste pickers were dissatisfied with their unhealthy working conditions, poverty and stigmatisation.Olanrewaju Dada, Lecturer, Department of Urban and Regional Planning, Olabisi Onabanjo University, Ago-Iwoye, Nigeria, Olabisi Onabanjo UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1527232021-01-18T11:26:23Z2021-01-18T11:26:23ZBacon: how you cook it could partially lower cancer risk<figure><img src="https://images.theconversation.com/files/378632/original/file-20210113-19-1ylo4tn.jpg?ixlib=rb-1.1.0&rect=12%2C0%2C4252%2C2845&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lightly-browned bacon has less carcinogens than well-cooked bacon.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/back-middle-bacon-frying-pan-traditional-313054742">D. Pimborough/ Shutterstock</a></span></figcaption></figure><p>Bacon is a much-loved, comforting breakfast item – during the global pandemic, sales have surged in <a href="https://www.provisioneronline.com/articles/109847-bacon-report-bacon-buying-bonanza">the US</a> and <a href="https://www.thegrocer.co.uk/top-products/the-fastest-growing-products-and-categories-during-the-pandemic-top-products-2020/651534">the UK</a>. But while bacon may be delicious, experts recommend people <a href="https://www.wcrf-uk.org/uk/preventing-cancer/cancer-prevention-recommendations">eat little or no</a> processed meats because of their cancer risk. But while the cancer risk from processed foods is certainly something to think about, that doesn’t mean bacon should be totally off the menu. In fact, you might be able to lower some of the cancer risk from eating bacon depending on how you cook it. </p>
<p>Nitrites are perhaps the best-known cancer risk in bacon. Nitrites are used as a preservative, and are also converted in the stomach into N-nitroso compounds (NOCs), which can cause cancer. </p>
<p>Some bacon products are now advertised as “nitrite-free”. However, some of these products merely replace synthetic nitrite with a vegetable source, which is still <a href="https://clinical-nutrition.imedpub.com/nitrates-nitrites-and-nitrosamines-from-processed-meat-intake-and-colorectalcancer-risk.php?aid=21326">converted into</a> NOCs. These carcinogens also form <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.1974.tb02883.x">when bacon is fried</a>. Some processed meats don’t contain nitrites and aren’t cooked (such as parma ham), so they carry a lower cancer risk compared to bacon.</p>
<p>But avoiding nitrites will not eliminate all cancer risks from bacon. This is because frying also generates two other major groups of carcinogens. One of these is a group called heterocyclic amines (HCAs). Fried bacon <a href="https://pubmed.ncbi.nlm.nih.gov/22129588/">contains more</a> HCAs than any other cooked meat, and <a href="https://pubmed.ncbi.nlm.nih.gov/20497781">high levels</a> of advanced glycation end products (AGEs) which are also linked to cancer.</p>
<p>Both HCAs and AGEs are produced by a chemical process called the Maillard reaction, which increases rapidly with heat. So your cancer risk could depend on how you cook your bacon. For instance, lightly browned bacon has only <a href="https://pubmed.ncbi.nlm.nih.gov/33371602/">one-tenth</a> the HCAs of well-cooked bacon. The Maillard reaction causes browning (thus producing carcinogens), so cooking methods where there’s little browning also usually result in fewer HCAs and AGEs. Hence microwaved bacon has far <a href="https://pubmed.ncbi.nlm.nih.gov/20497781/">lower levels</a> of AGEs than fried bacon. </p>
<p>Grilling/broiling bacon under a direct flame may also be unwise, as close contact with a naked flame generates very high temperatures that also cause drying on the surface of the bacon. <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1541-4337.2010.00141.x">Both of these factors</a> increase HCA formation.</p>
<p>As flavour comes with frying, many bacon lovers will probably baulk at the idea of only lightly fried bacon. Fortunately, it may be possible to reduce carcinogen production without compromising taste. This is because flavour molecules are produced by a <a href="https://pubmed.ncbi.nlm.nih.gov/23867544/">different part</a> of the Maillard reaction to that generating HCAs and AGEs. </p>
<figure class="align-center ">
<img alt="A pan of crisp bacon alongside other breakfast items, including eggs, tomatoes, and asparagus." src="https://images.theconversation.com/files/378787/original/file-20210114-13-1o7ql2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378787/original/file-20210114-13-1o7ql2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378787/original/file-20210114-13-1o7ql2h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378787/original/file-20210114-13-1o7ql2h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378787/original/file-20210114-13-1o7ql2h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378787/original/file-20210114-13-1o7ql2h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378787/original/file-20210114-13-1o7ql2h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Maillard reaction gives bacon colour – and carcinogens.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cooked-sizzling-hot-tasty-crispy-bacon-714132229">Elena Veselova/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Foods rich in antioxidants are able to reduce harmful oxidising chemical reactions. This may suppress the part of the Maillard reaction that leads to <a href="https://pubmed.ncbi.nlm.nih.gov/33371602/">HCAs</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/21779560/">AGEs</a>. Frying with a cooking oil rich in antioxidants – such as extra virgin olive oil – may lower cancer risk compared to frying in other cooking oils which are <a href="https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/can-rapeseed-oil-replace-olive-oil-as-part-of-a-mediterraneanstyle-diet/09863075B159BA2CDBA1A056E4FA1268">much lower</a> in antioxidants. </p>
<h2>Oesophageal cancer</h2>
<p>However, some groups may be at higher risk compared to others from the cancer-causing carcinogens in bacon. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/16507831/">Research</a> has found a strong association between eating processed meat and an increased risk of oesophageal cancer called <a href="https://www.nhs.uk/conditions/oesophageal-cancer/">oesophageal adenocarcinoma</a>. The UK has the <a href="https://pubmed.ncbi.nlm.nih.gov/16507831/">highest incidence</a> in the world of this deadly type of cancer.</p>
<p>The main pre-cancerous state for oesophageal adenocarcinoma is a condition called Barrett’s oesophagus. About 1 million people in the UK have Barrett’s oesophagus and around <a href="https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/oesophageal-cancer/risk-factors#heading-Five">3-13% of these people</a> will go on to develop oesophageal adenocarcinoma – an eleven-fold greater risk than the general population.</p>
<p>So people with Barrett’s oesophagus should be particularly wary of eating bacon. The link between oesophageal adenocarcinoma and bacon is inflammation, with <a href="https://pubmed.ncbi.nlm.nih.gov/24857183/">compelling evidence</a> showing inflammation drives Barrett’s oesophagus to cancer. For instance, people with an inflamed oesophagus (oesophagitis) have a four-fold increased risk of oesophageal adenocarcinoma compared with the general population. And for those already with Barrett’s oesophagus, oesophagitis increases the risk of developing oesophageal adenocarcinoma thirty-fold.</p>
<p>Diets high in inflammatory foods <a href="https://pubmed.ncbi.nlm.nih.gov/28571591/">are associated with</a> an increased risk of oesophageal adenocarcinoma. As AGEs found in bacon are potent inflammatory molecules <a href="https://pubmed.ncbi.nlm.nih.gov/30706806/">linked to</a> increased cancer risk, the exceptionally high levels of AGEs in bacon may pose a particular risk for oesophageal inflammation and oesophageal adenocarcinoma. However, no research has yet tested whether the inflammatory compounds in fried bacon make it more of a cancer risk than other processed meat. </p>
<p>Due to this lack of research, <a href="https://pubmed.ncbi.nlm.nih.gov/24165758/">current UK guidelines</a> for the management of Barrett’s oesophagus make no mention of diet. But given what we know more generally about the carcinogens in bacon causing cancer, it’s best to remain cautious.</p>
<p>Worryingly, only about 10% of people with Barrett’s oesophagus know they have it. The majority of people with undetected Barrett’s oesophagus will have developed it as a result of chronic acid reflux. So bacon lovers who are prone to acid reflux may want to avoid bacon while they seek out treatment.</p>
<p>Either way, a few simple steps can help lower cancer risk – such as gently frying bacon on a low heat, using extra virgin olive oil, or lower oven or grill temperatures and switching to non-fried, nitrite-free processed meats. Eating a healthy diet – such as the <a href="https://theconversation.com/vegan-or-mediterranean-diet-which-is-better-for-heart-health-110052">Mediterranean diet</a>, which is particularly effective at lowering inflammation in the body – may also help reduce overall risk.</p><img src="https://counter.theconversation.com/content/152723/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Hoffman has previously received funding from NIHR. He is the author of two books on the Mediterranean diet: The Mediterranean Diet: Health and Science (2011) and More Healthy Years - Why a Mediterranean Diet is best for you and for the planet (2020).</span></em></p>People with Barrett’s oesphagus may still want to be especially careful about eating bacon.Richard Hoffman, Associate lecturer, University of HertfordshireLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/995782018-07-23T10:12:18Z2018-07-23T10:12:18ZBreakthrough could end animal testing in carcinogen research<figure><img src="https://images.theconversation.com/files/227984/original/file-20180717-44076-caflg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lab mouse.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/success?u=http%3A%2F%2Fdownload.shutterstock.com%2Fgatekeeper%2FW3siZSI6MTUzMTg1MjIwNiwiYyI6Il9waG90b19zZXNzaW9uX2lkIiwiZGMiOiJpZGxfNjA1MjI2NTU0IiwiayI6InBob3RvLzYwNTIyNjU1NC9odWdlLmpwZyIsIm0iOjEsImQiOiJzaHV0dGVyc3RvY2stbWVkaWEifSwiRDM1emtNZklEY0pFcUkxb3IwdmRWcDI4aEZzIl0%2Fshutterstock_605226554.jpg&pi=33421636&m=605226554&src=pI7U5fqXdJskMTLX_u62Vg-1-2">Unol/Shutterstock</a></span></figcaption></figure><p>Animal testing has been at the heart of chemical safety assessments since the 1970s. Looking at the most recent figures, in 2011, <a href="https://eurl-ecvam.jrc.ec.europa.eu/validation-regulatory-acceptance/docs-carcinogenicity/analysis-of-carcinogenicity-testing-for-regulatory-purposes-in-the-european-union">more than a million animals</a> were used to test whether chemicals would be harmful to humans in Europe alone. While in 2016, <a href="https://www.gov.uk/government/statistics/statistics-of-scientific-procedures-on-living-animals-great-britain-2016">180,000 animals</a> were used to assess chemical safety in the UK. </p>
<p>Every year, around 12,000 rodents are involved in European carcinogenicity studies, to test whether a chemical could cause cancer. More than 600 rodents are tested on with each chemical, and monitored for cancer growth over two years. </p>
<p>There is widespread consensus that we should find alternatives to animal testing. Obviously, there are the ethical concerns – no one wants to see animals used if there are alternatives. But there are economic and biological arguments, too. Animal testing carries a high cost. But the striking driver here is that human biology differs significantly from that of rodents. Humans are not big mice so relying on rodent data to predict human carcinogenicity <a href="https://theconversation.com/of-mice-and-men-why-animal-trial-results-dont-always-translate-to-humans-73354">can be flawed</a>.</p>
<h2>Identifying carcinogens</h2>
<p>Most carcinogens induce cancer by causing damage to cell DNA (known as genotoxicity). This damage leads to DNA mutations that alter the structure and function of the key genes in our bodies which are responsible for controlling cell growth. Mutated genes drive cancer development by allowing cells to divide uncontrollably and invade surrounding tissues. As the cells divide rapidly, they acquire new DNA mutations, so a vicious circle of accelerated mutation ensues.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/226699/original/file-20180709-122274-1yp4br7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/226699/original/file-20180709-122274-1yp4br7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/226699/original/file-20180709-122274-1yp4br7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=564&fit=crop&dpr=1 600w, https://images.theconversation.com/files/226699/original/file-20180709-122274-1yp4br7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=564&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/226699/original/file-20180709-122274-1yp4br7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=564&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/226699/original/file-20180709-122274-1yp4br7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=709&fit=crop&dpr=1 754w, https://images.theconversation.com/files/226699/original/file-20180709-122274-1yp4br7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=709&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/226699/original/file-20180709-122274-1yp4br7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=709&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A cell bearing a DNA damaging event (a micronucleus). Two nuclei are visible, alongside a small chromosome fragment.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>As genotoxicity underlies the actions of most carcinogens, a lot of safety testing for carcinogens focuses on its detection. Initially, it can be detected in simple cell-based systems (“in vitro”). These are cell models grown either in 2D sheets on the bottom of a tissue culture flask, or floating in suspension in a tissue culture medium (a rich nutrient fluid in which cells readily grow).</p>
<p>This type of testing is mostly successful – 80-90% of carcinogens are detectable with genotoxicity tests. However, around 10-20% of carcinogens aren’t. These “non-genotoxic” carcinogens are more complicated, and cause cancer through indirect routes. The lack of detection of non-genotoxic carcinogens, and some problems with existing cell-based genotoxicity tests (safe compounds erroneously being labelled as carcinogens, for example) are partly behind the continued reliance on animal testing.</p>
<h2>Animal testing alternatives</h2>
<p>Our <a href="https://twitter.com/ivtg_swansea?lang=en">research group</a> is focused on designing new, more specific and more sophisticated cell-based tests for carcinogens. We <a href="https://www.ncbi.nlm.nih.gov/pubmed/29110037">recently published results</a> from a five-year study which outlined how, by coupling together multiple human cell abnormalities known to be important in cancer development, we are better able to identify carcinogens in vitro. Crucially, this approach can be used to detect both genotoxic and non-genotoxic carcinogens. </p>
<p>As our proposed test assesses genotoxicity, genotoxic carcinogens continue to be detected – but it can detect non-genotoxic carcinogens as well. We found that non-genotoxic carcinogens were detectable through their ability to alter both gene expression and cell morphology – the size, shape and behaviour of the cells.</p>
<p>But it is important to note that no matter how sophisticated our cell-based testing models are, questions still arise over whether they can be truly representative of complex human organs and systems. So, with that in mind, we are now working to further develop human tissue models to better reflect human physiology. We are hoping to adapt our test using 3D models <a href="https://www.ncbi.nlm.nih.gov/pubmed/29307375">of human liver</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/24675152">skin</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/27955700">lung</a> to more closely mimic human physiology.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/226725/original/file-20180709-122271-1j7urtz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/226725/original/file-20180709-122271-1j7urtz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/226725/original/file-20180709-122271-1j7urtz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=563&fit=crop&dpr=1 600w, https://images.theconversation.com/files/226725/original/file-20180709-122271-1j7urtz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=563&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/226725/original/file-20180709-122271-1j7urtz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=563&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/226725/original/file-20180709-122271-1j7urtz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=707&fit=crop&dpr=1 754w, https://images.theconversation.com/files/226725/original/file-20180709-122271-1j7urtz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=707&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/226725/original/file-20180709-122271-1j7urtz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=707&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Liver spheroid: a 3D construct containing 50,000 liver cells, growing together in a tissue matrix.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In addition, as humans develop more and more new materials, it is not just chemicals that need safety testing. There is increasing concern about new nanomaterials, for example, that promise to revolutionise everything from aerospace to medicines and consumer products. The human toxicity and carcinogenicity of nanomaterials is currently unknown. But again, using an in vitro test and 3D tissue models could prevent the need for animals ever to be tested on with nanomaterials. </p>
<p>We believe that this kind of analysis – which looks at numerous cancer-relevant abnormalities at the same time – can successfully detect the vast majority of carcinogens, and may herald the end of animal testing in this field. In recent years, the EU has <a href="https://ec.europa.eu/growth/sectors/cosmetics/animal-testing_en">banned animal testing for cosmetics</a> and we hope that, with further development, our approach to carcinogens will remove the need for animal testing across other chemical sectors, too. Not only does it have the potential to prevent animals’ potential suffering, it will also improve human safety.</p><img src="https://counter.theconversation.com/content/99578/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gareth Jenkins receives funding from the NC3Rs, Unilever, Cancer Research Wales. </span></em></p><p class="fine-print"><em><span>Shareen Doak receives funding from the European Union’s Horizon 2020 research and innovation programme, INTERREG Ireland-Wales programme, Unilever and NC3Rs. </span></em></p>Humans are not big mice so why are we still testing on these animals?Gareth Jenkins, Professor, Swansea University Medical School, Swansea UniversityShareen Doak, Professor of Genotoxicology and Cancer, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/953872018-04-23T15:07:20Z2018-04-23T15:07:20ZFact Check: does coffee cause cancer?<figure><img src="https://images.theconversation.com/files/215952/original/file-20180423-133881-4xj6sy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><blockquote>
<p>While plaintiff offered evidence that consumption of coffee increases the risk of harm to the fetus, to infants, to children and to adults, defendants’ medical and epidemiology experts testified that they had no opinion on causation.</p>
</blockquote>
<p><strong>California Superior Court Judge Elihu Berle, <a href="http://cdn.cnn.com/cnn/2018/images/03/29/coffee.proposed.stmt.of.decision.after.trial.pdf">proposed ruling</a> on Council for Education and Research on Toxics vs. Starbucks Corporation et al, March 28 2018.</strong></p>
<p>A California judge <a href="https://www.washingtonpost.com/news/to-your-health/wp/2018/03/29/coffee-must-carry-cancer-warning-california-judge-rules/?utm_term=.9758d1ee38ef">recently ruled</a> that Starbucks and other coffee companies in the state must serve the drink with a cancer warning. The legal issue comes from the presence of acrylamide in coffee. This chemical is typically found in many foods with a high carbohydrate content that are exposed to high temperatures, including cakes, potato crisps, bread and cereals. <a href="https://academic.oup.com/carcin/article/28/3/519/2476708">Evidence shows that acrylamide</a> is <a href="http://monographs.iarc.fr/ENG/Classification/latest_classif.php">probably a human carcinogen</a>, a cancer-causing substance.</p>
<p>The acrylamide in coffee is formed early in the roasting process, which turns the fresh green beans the dark brown colour we are familiar with and gives coffee its deep bitter flavour. Once inside the body, acrylamide can be converted to another compound, epoxide glycidamide, and both of these chemicals can bind to and <a href="https://www.sciencedirect.com/science/article/pii/S0041008X08005024?via%3Dihub">damage our proteins and DNA</a>. Damage to DNA can be the first step in the development of cancer, and <a href="https://www.ncbi.nlm.nih.gov/pubmed/17492525">acrylamide also interferes with DNA repair</a>.</p>
<p>The problem with the recent court ruling was that person bringing the case only needed to show there were trace amounts of acrylamide in coffee in order to succeed. This is where the reality of our lifestyles makes the ruling seem over-cautious.</p>
<p>Nobody disputes that coffee contains acrylamide or that acrylamide causes DNA damage, but it’s how much you consume that is important. The risk is really related to the total sum of exposure over a lifetime, but <a href="https://www.sciencedirect.com/science/article/pii/S027869150900564X">one estimate</a> suggests an 80kg adult consuming less than 208 micrograms of acrylamide a day should not have any increased risk of cancer.</p>
<p>The main lifestyle choice that exposes people to toxins is smoking. Each cigarette contains around <a href="https://www.ncbi.nlm.nih.gov/pubmed/18718145">2.3 micrograms</a> of acrylamide, among a cocktail of other carcinogens. But all the foods we roast or fry to get delicious caramelisation also contain acrylamide. So non-smokers’ lifestyles are not acrylamide-free, with 5 micrograms in a slice of toast or 7 micrograms in a bag of potato crisps, <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/mnfr.200500029">as examples</a>.</p>
<p>A cup of coffee fits into our daily acrylamide exposure at around <a href="https://pubs.acs.org/doi/abs/10.1021/jf0349634">0.9 micrograms to 2.4 micrograms</a> per 150 millilitre cup. But every cup also contains a <a href="https://www.mdpi.com/1420-3049/19/11/19180">diverse array of anti-oxidants</a> and <a href="https://www.bmj.com/content/359/bmj.j5024.long">other compounds</a> thought to have positive health effects (outside of pregnancy).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/215953/original/file-20180423-133865-13q1nrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/215953/original/file-20180423-133865-13q1nrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/215953/original/file-20180423-133865-13q1nrs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/215953/original/file-20180423-133865-13q1nrs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/215953/original/file-20180423-133865-13q1nrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/215953/original/file-20180423-133865-13q1nrs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/215953/original/file-20180423-133865-13q1nrs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Warning: a tiny amount of carcinogen ahead.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The same group of scientists (working for the World Health Organisation), who classified acrylamide as probably carcinogenic, found there was <a href="https://www.sciencedirect.com/science/article/pii/S147020451630239X?via%3Dihub">no conclusive evidence</a> that drinking coffee caused cancer. In fact, they suggested coffee drinking may <a href="https://www.sciencedirect.com/science/article/pii/S147020451630239X?via%3Dihub">protect against</a> liver and endometrial cancers and <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/cas.13328">more recent studies</a> have supported this idea. In 2016, the WHO took coffee <a href="https://theconversation.com/raise-a-cup-of-coffee-who-no-longer-says-it-can-cause-cancer-60096">off its list</a> of possible carcinogens.</p>
<p>Scientists’ original concern over coffee drinking followed studies that suggested a <a href="http://monographs.iarc.fr/ENG/Monographs/vol51/">possible link with bladder cancer</a>. But closer analysis of the data and <a href="https://journals.lww.com/epidem/Abstract/2017/09000/A_Prospective_Investigation_of_Coffee_Drinking_and.8.aspx">larger scale studies</a> showed that the original research was confused by not taking account of smoking habits. It’s possible that coffee drinking interacts with smoke carcinogens to increase the risk of bladder cancer for smokers. In non-smokers, there is no robust evidence of a link between coffee and bladder cancer.</p>
<p>If you’re still worried about the acrylamide in coffee, it’s worth noting that <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/mnfr.200600069">less acrylamide</a> seems to make it into the cup when the coffee is filtered than made using the espresso method. The choice of beans and roasting time might be important too since Robusta contains <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/mnfr.200600069">more acrylamide</a> than Arabica, and darker roasts <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/mnfr.200600069">contain less</a> than lighter ones.</p>
<h2>Verdict</h2>
<p>Acrylamide isn’t good for you but the amount present in coffee makes no observable contribution to cancer risk. There is no strong evidence for a link between drinking coffee and developing cancer. While there have been occasional studies suggesting an increased risk in bladder cancer, overall the vast majority of rigorous studies suggest that if coffee drinking has any effect at all it actually offers a mild protective effect from some cancer types.</p>
<h2>Review</h2>
<p><strong>Annie Anderson, professor of public health nutrition at the University of Dundee</strong></p>
<p>This article provides a fair, evidence-based reflection on coffee and cancer with a focus on acrylamide. The science sources cited are robust and the case well made for coffee being one source of acrylamide, which is the one component indicated as a carcinogen. The work from the WHO scientists is particularly notable in this respect.</p>
<p>Acrylamide is a nasty carcinogen and keeping intakes down is highly recommended, as a UK government report <a href="https://cot.food.gov.uk/sites/default/files/finalacrylamidestatement.pdf">recently reaffirmed</a>, and <a href="https://www.bmj.com/content/bmj/351/bmj.h4501.full.pdf">especially for pregnant women</a>.</p>
<p>Coffee is one source among many (others are mostly high starch foods cooked at high temperature). Cutting back on these foods is all well and good but the amount of acrylamide we consume is probably more determined by what the food industry feeds us, the raw ingredients it uses, the cooking temperatures in processing and so on. Worrying about the relatively small amounts of acrylamide consumed through coffee is not half as helpful as what the industry action could do. </p>
<p><a href="https://www.bmj.com/content/360/bmj.k322">Recent research showing</a> a link between ultra-processed food and cancer risk means we need to think way beyond coffee and remember that, as part of a plant-based diet, it may actually be protective against at least two cancers.</p><img src="https://counter.theconversation.com/content/95387/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Baker receives funding from the charities York Against Cancer and the Wellcome Trust. While he has no financial interests in the coffee industry, he does drink several cups a day.</span></em></p><p class="fine-print"><em><span>Annie Anderson receives funding from Scottish Government, MRC, WCRF,,NIHR, FP7 and is co-director of the Scottish Cancer Prevention Network and has an interesting relationship with coffee due to caffeine sensitivity.</span></em></p>A California judge ruled coffee should carry a cancer warning label but the evidence says something very different.Simon Baker, Bladder cancer researcher, University of YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/768982017-06-05T01:05:30Z2017-06-05T01:05:30ZIs the developed world we’ve created giving us cancer?<figure><img src="https://images.theconversation.com/files/171727/original/file-20170531-25658-jprees.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists know that many toxins, such as those found in cigarettes, cause most lung cancers, whose cells are depicted here. But isolating causes for other cancers is an ongoing effort.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/233501644?src=6889AeD-KrvZJJs-1VN0ow-2-52&size=huge_jpg">Raj Creationzs/Shutterstock</a></span></figcaption></figure><p>I had assumed that the small lump in my breast was a blocked milk duct from nursing my seven-month-old son. The news that I had stage 2 breast cancer stunned.</p>
<p>“But it’s not in my family,” I told the radiologist. “And I have a healthy lifestyle! Why did I get breast cancer?” </p>
<p>In one way or another, friends and relatives here in the U.S. asked the same question. Why had this happened to me? Their explanations coalesced around a single point: bad genes. </p>
<p>But when I told my friends and host family in Haiti, where I’ve been studying social and political life for the past decade, their reactions were different. They asked: Who had done this to me? Was a colleague angry? Was a family member getting revenge? Or was someone simply jealous, especially after the good year I’d had landing a new job, having a baby, buying a house and having the Cubs win the World Series? Someone must have wished me ill will. </p>
<p>Hearing these interpretations awakened me from the foggy shock of the initial diagnosis, and I started to look at cancer with my professional eye as an anthropologist. </p>
<p>My first realization was that the Americans’ and Haitians’ answers were not so different. Both responses located breast cancer as something that happens to someone else – to someone saddled with bad family genes, or someone who stokes jealousies. The responses shielded my kindred from acknowledging that cancer is something that could happen to anyone – that it could happen to them. </p>
<h2>Cancer incidence increasing</h2>
<p><a href="http://www.breastcancer.org/symptoms/understand_bc/statistics">One in eight</a> American women will suffer breast cancer during their lifetimes. Some form of cancer will afflict nearly half – yes, <a href="https://www.cancer.org/cancer/cancer-basics/lifetime-probability-of-developing-or-dying-from-cancer.html">one in two</a> – of Americans. </p>
<p>This is not merely because we’re living longer. <a href="http://articles.latimes.com/2013/feb/26/science/la-sci-breast-cancer-younger-women-20130227">Cases of younger women</a> with invasive breast cancer have increased 2 percent annually since the mid-1970s. </p>
<p>As far as cancer rates in Haiti go, reliable statistics do not exist. But we do know that cancers are on a <a href="https://www.hindawi.com/journals/jo/2013/206367/">steep rise</a> there and across the developing world, especially for younger people. We also know that this rise has a lot to do with the toxins, pollutants, diets and lifestyles that accompany development. </p>
<p>Considering these numbers, I realized that I was asking the wrong question, and that the answers I was receiving, be they from U.S. or Haitian confidants, were incomplete. </p>
<p>The question should not be why did I get breast cancer, but why are we getting it.</p>
<h2>Toward a holistic understanding</h2>
<p>As an anthropologist, I approach social problems holistically. I strive to understand the big picture that is often lost by focusing on singular variables: genes, jealousy. Holism encourages us to look beyond linear relationships of cause and effect and toward the assembly of forces that together influence our behaviors, conditions and outcomes. </p>
<p>In her book <a href="http://www.ucpress.edu/book.php?isbn=9780520276574">“Malignant</a>,” anthropologist S. Lochlann Jain equates cancer to a “total social fact.” She says cancer is “a practice whose effects fissure through seemingly distinct areas of life, thus weaving them together.” The rise of cancer as a leading cause of death traces the history of industrialization, the development of social, economic and political practices that define the “developed” world, from agribusiness to industrial chemicals to Superfund sites. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/171840/original/file-20170601-25658-g9o7wx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171840/original/file-20170601-25658-g9o7wx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171840/original/file-20170601-25658-g9o7wx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171840/original/file-20170601-25658-g9o7wx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171840/original/file-20170601-25658-g9o7wx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171840/original/file-20170601-25658-g9o7wx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171840/original/file-20170601-25658-g9o7wx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The World Health Organization has listed processed meats such as hot dogs and bacon as carcinogenic, but they are still popular foods.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-boy-eats-huge-hotdog-sandwich-283664600?src=uGjiPbGGair2Of9htfMuEA-1-16">Bill Nagy/Shutterstock</a></span>
</figcaption>
</figure>
<p>When I broaden my gaze, <a href="https://www.cancer.org/cancer/cancer-causes/general-info/known-and-probable-human-carcinogens.html">carcinogens appear everywhere</a>: in pesticide-treated produce, hormone-treated meat and dairy products, flame-retardant clothing and upholstery, cosmetics, birth control pills, household cleaners and soaps, gas fumes and the plastics that make up our world. Cancer infiltrates how we feed, clothe, clean, beautify and reproduce ourselves. </p>
<p>Granted, it is difficult to test all these factors to see which of them is killing us, and to what degree, if at all. There is no way to fit this cancerous environment, in all its entangled complexity, into a randomized control trial. We are all “exposed” as a fact of life. There is no control group. </p>
<p>But then again, if we continue to focus on the trees, we lose the forest. The problem is akin to discussions about climate change. It must be addressed not through piecemeal changes but comprehensive policies that target a way of life on Earth. We need to not only research and regulate specific poisons, like cigarettes or lead, but also to study the simultaneous and cumulative consequences of lifetime exposure to known carcinogens and contaminants in the environment. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/171845/original/file-20170601-25700-1fym7wf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171845/original/file-20170601-25700-1fym7wf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=377&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171845/original/file-20170601-25700-1fym7wf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=377&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171845/original/file-20170601-25700-1fym7wf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=377&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171845/original/file-20170601-25700-1fym7wf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171845/original/file-20170601-25700-1fym7wf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171845/original/file-20170601-25700-1fym7wf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cigarettes are among the most carcinogenic products on Earth, killing millions of people each year.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/box-cigarettes-384028573?src=UjZWf9Y-vgl7JToPa9e7wQ-1-8">Benjamas11/Shutterstock</a></span>
</figcaption>
</figure>
<p>Why do people, across cultures and societies, tend to focus on the individual person as the unit of analysis? </p>
<p>For one, it is fundamentally easier than focusing on a system: social, political or ecological. Laying blame on a person or a gene also plays neatly into the cultural metaphors we’ve sustained about all sorts of illness: that disease is a consequence of personal rather than societal failings. This certainly locates blame in the afflicted, protecting the well from facing their individual fears of illness. But it severely limits our ability to understand and eradicate collective epidemics, like cancer. </p>
<p>To be sure, <a href="http://ww5.komen.org/BreastCancer/InheritedGeneticMutations.html">genetics play a role in cancer</a>, but that role has been wildly overstated. Fewer than 10 percent of women can trace their tumorous breasts to any genetic mutation, and fewer than 5 percent to the so-called breast cancer genes, BRCA 1 and 2. I am among the other 90 percent.</p>
<p>And yet, the bulk of funding for medical cancer research has focused on genetic causes, with only 15 percent of the <a href="https://deainfo.nci.nih.gov/advisory/pcp/annualreports/pcp08-09rpt/pcp_report_08-09_508.pdf">National Cancer Institute budget</a> dedicated to environmental oncology. </p>
<h2>Not a hex, but a vexing range of reasons</h2>
<p>There is also some truth to the interpretations offered by my Haitian friends. I do not believe my cancer is caused by a hex. But the language of sorcery, which targets people as the source of illness, does raise relevant social factors beyond the biological family. Jealousies speak to the very real connections between social inequities, antipathies, stress and illness. Still, this explanation did not zoom out and grapple with the carcinogenic environment recently imported from the developed world. </p>
<p>Over the years I’ve worked in Haiti, I have witnessed diets shift from a variety of grains and tubers to imported rice, pasta and sugary snacks, the simple carbohydrates associated with <a href="http://www.webmd.com/breast-cancer/news/20150115/unhealthy-insulin-levels-may-boost-breast-cancer-risk#1">higher insulin levels and increased breast cancer risk</a>. Plastics have also invaded the country. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/172058/original/file-20170602-20599-gld4d7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/172058/original/file-20170602-20599-gld4d7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=435&fit=crop&dpr=1 600w, https://images.theconversation.com/files/172058/original/file-20170602-20599-gld4d7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=435&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/172058/original/file-20170602-20599-gld4d7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=435&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/172058/original/file-20170602-20599-gld4d7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=547&fit=crop&dpr=1 754w, https://images.theconversation.com/files/172058/original/file-20170602-20599-gld4d7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=547&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/172058/original/file-20170602-20599-gld4d7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=547&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A woman and a boy collect plastic trash in a street in Port-au-Prince, Haiti.</span>
<span class="attribution"><span class="source">Chelsey Kivland.</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Most people get their daily water from plastic sachets that, under the hot sun, degrade and leak <a href="https://www.sciencedaily.com/releases/2009/03/090326100714.htm">cancer-causing xenoestrogens</a>. And then there are industrial agriculture, family planning initiatives or the leftover, processed meats repackaged and sold in Haiti. </p>
<p>If we continue to think of cancer as happening to other people, we will fail to ask the big questions, let alone answer them. </p>
<p>This idea first glimmered when my otherwise kind, smart doctor brushed off my environmental worries with a shrug of futility. “You can’t escape the world,” he said. </p>
<p>That may be true, but we make the world. “Through a continued, unrestrained, needless, avoidable, and in part reckless increasing contamination of the human environment,” the <a href="https://deainfo.nci.nih.gov/advisory/pcp/annualreports/pcp08-09rpt/pcp_report_08-09_508.pdf">U.S. President’s Cancer Panel</a> reported in 2010, “the stage is being set for an acute, catastrophic epidemic.” </p>
<p>The steep and recent rise in cancer in the developing world, terrible as it is, teaches us that another, less polluted world once existed. Can it again be possible?</p><img src="https://counter.theconversation.com/content/76898/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chelsey Kivland does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>What causes cancer? A scary truth might be that we have created an environment for it. An anthropologist’s search for answers to her own diagnosis raises questions for all of us.Chelsey Kivland, Professor of Anthropology, Dartmouth CollegeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/677622016-11-15T02:55:02Z2016-11-15T02:55:02ZTattoo regret: Can you make it go away?<figure><img src="https://images.theconversation.com/files/143959/original/image-20161031-15816-1ximt4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">About one in four people regrets having tattoos. </span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-4205917/stock-photo-tattoo-man-with-headache.html?src=4ycHcrsuQD-7BWOkN56KJQ-1-5">From www.shuttertock.com</a></span></figcaption></figure><p>Almost half of people between 18 and 35 have tattoos, and almost one in four regrets it, according <a href="http://www.theharrispoll.com/health-and-life/Tattoo_Takeover.html">to a 2016 Harris Poll</a>. Based on an estimate of about 60 million people in that age group, that would mean that about 7.5 million people have tattoo regret.</p>
<p>As a primary care physician, I’ve noticed anecdotally that many of my younger patients have regrets about their tattoos. When I ask about them, many say that they got them when they were young, and at the time put little or no research into the decision.</p>
<p>With no source (reliable or otherwise) of tattoo information to suggest to my patients, I began to investigate the topic myself. My goal was to write a quick reference for teens that reviewed the health and social issues they might encounter after getting a tattoo.</p>
<p>What I found was myriad unexpected and sometimes shocking concerns that everyone should know. To my surprise, there were a host of reports of ink complications, infections, toxin effects, scarring, burns, chronic irritations and much more.</p>
<h2>The ink goes more than skin deep</h2>
<p>Among the concerns are the <a href="http://www.tandfonline.com/doi/full/10.1586/eci.10.10">long-term effects</a> tattoo inks can have on the immune system, pathology specimen interpretation and other unforeseen health complications. </p>
<p>Certain tattoo inks can be toxic, with some containing carcinogenic compounds, a <a href="http://mst.dk/service/publikationer/publikationsarkiv/2012/jun/chemical-substances-in-tattoo-ink/">2012 Danish Environmental Protection Agency</a> found. In fact, <a href="https://theconversation.com/one-in-five-tattoo-inks-in-australia-contain-carcinogenic-chemicals-63947">one in five tattoo inks</a> contained carcinogenic chemicals, and a vast majority of the inks tested did not comply with international health safety standards for ink composition, an <a href="https://healthunlocked.com/cllsupport/posts/134137692/one-in-five-tattoo-inks-in-australia-contain-carcinogenic-chemicals">Australian government-sponsored study</a> found. Even more concerning, carcinogens were identified in 83 percent of black inks – by far the most popular color for tattoos.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/143962/original/image-20161031-15728-zokefc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/143962/original/image-20161031-15728-zokefc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/143962/original/image-20161031-15728-zokefc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/143962/original/image-20161031-15728-zokefc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/143962/original/image-20161031-15728-zokefc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/143962/original/image-20161031-15728-zokefc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/143962/original/image-20161031-15728-zokefc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Tattoo inks can be unsafe.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-400561009/stock-photo-replacement-supplies-for-tattoo-in-sterile-packages-sketches-inks-and-a-tattoo-machine-on-the-white-background-of-old-boards.html?src=N6DVsRLqUBQMOAfWrJw8kg-1-3">From www.shutterstock.com</a></span>
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<p>The <a href="http://estpresearch.org/">European Society of Tattoo and Pigment Research</a> was established in 2013 with a mission of educating the public about the <a href="http://estpresearch.org/tattoo-campaign/worth-knowing-about-tattoos.html">“fundamental facts about tattooing”</a> which many in the younger generations ignore. That group found barium, copper, mercury and other unsafe components in tattoo inks. Their research also found a disheartening mismatch between the listed ink container contents and its actual chemical composition found on testing.</p>
<p>More recently, the Food and Drug Administration has become more involved with tattoo inks, stating “Many pigments used in tattoo inks are industrial-grade colors suitable for printers’ ink or automobile paint.” Like the studies started overseas, the agency is now examining the chemical composition of inks and pigments and how they break down in the body, as well <a href="http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm048919.htm">their short- and long-term safety</a>.</p>
<h2>Tattoos have led to errors in medical treatment, testing</h2>
<p>Metal-based ink tattoos can react with magnetic resonance imaging studies. For instance, two <a href="http://www.ajronline.org/doi/full/10.2214/ajr.174.6.1741795">case studies</a> detail patients who suffered <a href="http://sph.sagepub.com/content/3/5/431.short">MRI-induced burns</a> in their tattoos that were attributed to iron compounds in tattoo pigments. Radiologists say this magnet-based reaction is rare, but some have suggested simply avoiding iron-based tattoo inks.</p>
<p>Pathologists, meanwhile, are reporting <a href="http://onlinelibrary.wiley.com/doi/10.1111/tbj.12258/abstract">tattoo ink in surgical biopsy specimens of lymph nodes</a>. For instance, a 2015 report in the journal <a href="http://journals.lww.com/greenjournal/Citation/2015/07000/Extensive_Tattoos_Mimicking_Lymphatic_Metastasis.28.aspx">Obstetrics and Gynecology</a> detailed the case of a young woman with cervical cancer which doctors believed had spread to her lymph nodes. After surgery to remove the nodes, they discovered that what appeared to be malignant cells in a scan was actually tattoo ink. A similar <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1325237/">misdiagnosis</a> occurred in another patient with melanoma.</p>
<h2>And then there are the infections</h2>
<p>The most common infections associated with tattooing <a href="http://www.clinicalcorrelations.org/?p=4240">involve staphylococcus aureus or pseudomonas</a> bacteria arising from poor skin preparation or equipment sterilization. <a href="http://www.merckmanuals.com/home/infections/bacterial-infections/staphylococcus-aureus-infections">“Staph” skin infections</a> can become serious and even life-threatening, as antibiotic-resistant strains become more prevalent.</p>
<p>Three percent of tattoos get infected, and almost four percent of people who get tattoos recount pain lasting more than a month, a 2015 study from <a href="https://www.ncbi.nlm.nih.gov/pubmed/26509942">Tulane University School of Medicine</a> found. About 22 percent of participants with new tattoos reported persistent itching that lasted more than a month.</p>
<p>A spate of <a href="https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6133a3.htm">mycobacterial skin infections</a> in 22 people across four states in 2011 and 2012 was tied to a few specific brands of ink. The Centers for Disease Control and Prevention, in conjunction with local departments of public health, were able to contain these infections through intense tracking and investigation.</p>
<p>More serious tattoo-induced skin disorders like <a href="http://ijdvl.com/article.asp?issn=0378-6323;year=2013;volume=79;issue=2;spage=231;epage=234;aulast=Sanghavi">sarcoidosis, lichen planis and lupus-like reactions</a> are increasingly reported in current literature. These skin problems can be more long-lasting and leave permanent scarring.</p>
<p>A study reported in <a href="http://onlinelibrary.wiley.com/doi/10.1002/hep.26245/full">Hepatology</a> found that “tattoo exposure is associated with HCV (hepatitis C virus) infection, even among those without traditional risk factors. All patients who have tattoos should be considered at higher risk for HCV infection and should be offered HCV counseling and testing.” </p>
<p>Hepatitis, which is <a href="https://aidsinfo.nih.gov/guidelines/html/4/adult-and-adolescent-oi-prevention-and-treatment-guidelines/345/hcv">10 times more infectious than HIV</a>, can be transmitted through needles used by tattoo artists. It is the reason the <a href="http://www.redcrossblood.org/donating-blood/eligibility-requirements/eligibility-criteria-alphabetical-listing">American Red Cross</a> restricts blood donations from individuals with newer tattoos done outside of regulated tattoo facilities.</p>
<p>A study from <a href="https://www.ncbi.nlm.nih.gov/pubmed/26509942">Tulane University</a> added credence to these blood donation restrictions by showing that 17 percent of all participants had at least one tattoo done somewhere other than a tattoo parlor, and 21 percent admitted to being intoxicated while receiving at least one of their tattoos.</p>
<h2>A youthful decision with adult implications</h2>
<p>The primary reason Harris Poll respondents reported tattoo regret was they “were too young when they had it done.” The second most common reason, which coincides with the first, is the tattoo “didn’t fit their present lifestyle.”</p>
<p>Whether a tattoo depicts a name, a person, a place or a thing, its meaning and perception are in constant flux. <a href="http://www.academia.edu/4314436/Regret_in_American_Tattoo_Narratives_-_Madfis_and_Arford_2013">Eric Madfis and Tammi Arford</a>, writing about the dilemma of symbols and tattoo regret, note that “Symbols are dynamic in that they are time-specific, ever-changing, and always in a state of gradual transition.”</p>
<p>Tattoos have a different meaning depending on the interpreter, their relative history and knowledge, and they are dynamic because they can take on different meanings through time and experience. The first person to get a barbed wire tattoo on an upper arm could be seen as clever, inventive, unique and trail-blazing. The one-hundredth person to get the same tattoo was none of these things, and with time, if either was seen in public, both would receive the same reaction.</p>
<p>The “emotional response in the beholder” of any given tattoo can be based on “social stratification” and is not consistently predictable, according to <a href="http://wes.sagepub.com/content/29/1/60.full">Andrew Timmings at the University of St Andrews</a> in the United Kingdom. Their interviews of hiring managers showed that tattoos can actually hurt job prospects.</p>
<p>Another <a href="http://www.bizjournals.com/tampabay/news/2015/03/18/ut-study-even-college-kids-think-visible-tattoos.html">study, at the University of Tampa,</a> confirmed that 86 percent of students believe that having a visible tattoo is a detriment to their business prospects. </p>
<p>Researchers at the Harris Poll found that older respondents are less tolerant of visible tattoos as the prestige of the job position rises. While a vast majority of people age 51 and above are comfortable with professional athletes having tattoos, the acceptance decreases significantly when doctors, primary school teachers and presidential candidates are included.</p>
<p>Understandably, people who have many friends and family with tattoos are generally less stigmatized regarding their tattoo, and tend to suffer less tattoo regret, a study in <a href="http://www.sciencedirect.com/science/article/pii/S0362331914000081">The Social Science Journal</a> reported in 2014. But the study also found that when tattooed respondents were exposed to individuals without tattoos, like in the workplace or institutions of higher learning, more stigma victimization occurred, and those impacted were more likely to suffer regret and ponder removal.</p>
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<img alt="" src="https://images.theconversation.com/files/143964/original/image-20161031-15821-1rwnlol.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/143964/original/image-20161031-15821-1rwnlol.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/143964/original/image-20161031-15821-1rwnlol.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/143964/original/image-20161031-15821-1rwnlol.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/143964/original/image-20161031-15821-1rwnlol.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/143964/original/image-20161031-15821-1rwnlol.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/143964/original/image-20161031-15821-1rwnlol.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">People often regret getting married when young, just as they do with tattoos.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-467226644/stock-photo-wedding-wedding-day-paper-flowers-in-wedding-decor-bride-and-groom-on-wedding-ceremony-with-luxury-wedding-decoration-wedding-decoration-ceremony-beautiful-bride-and-elegant-groom-on.html?src=iQnpO7yzW2tlQDNi_khcLg-1-55">From www.shutterstock.com</a></span>
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<p>Getting a tattoo, which is akin to a life-changing (and body-changing) decision, when young is really no different from getting married young (<a href="http://family-studies.org/want-to-avoid-divorce-wait-to-get-married-but-not-too-long/">32 percent regret rate</a>) or choosing a college major (<a href="http://economix.blogs.nytimes.com/2012/05/14/regrets-about-college/">37 percent change rate</a>). For many, making a major decision when young is rife with regret. The difference with tattoos is having to face that regret on a daily basis.</p>
<p>As the pure number who have tattoos grow, the market for getting these tattoos removed has also found its niche. <a href="http://www.huffingtonpost.com/hilary-kramer/tattoo-removal-a-bigger-b_b_474675.html">Laser tattoo removal services have rapidly grown</a> across the nation and have become a multi-million dollar business, with additional <a href="http://www.fool.com/investing/general/2012/09/07/the-next-billion-dollar-industry-tattoo-removal.aspx">potential for growth</a> as the younger, highly tattooed, generations age.</p>
<h2>But some problem tattoos can’t be removed</h2>
<p>Current lasers still have limitations in the colors they can erase with added difficulty stemming from more vibrant tattoo colors. <a href="http://onlinelibrary.wiley.com/doi/10.1111/bjd.12526/full">Darker pigmented people</a> tend to have less success with certain lasers and require more sessions to avoid skin damage. </p>
<p>Because the <a href="http://jcasonline.com/article.asp?issn=0974-2077;year=2015;volume=8;issue=1;spage=25;epage=29;aulast=Shah">laser shatters the pigment particles</a> under the skin for removal by the body, the issues with infections, scarring and the ink spreading become a concern again. Tattoos covering extensive areas of the body are simply too large to tackle in one session, and could take years to remove. </p>
<p>Laser complications include pain, blistering, scarring and, in some cases, a darkening of the tattoo ink can occur, <a href="http://jcasonline.com/article.asp?issn=0974-2077;year=2015;volume=8;issue=1;spage=30;epage=36;aulast=Khunger">according to dermatologists.</a></p>
<p>As technology and the demand for tattoo removal advances, some of the limitations of current lasers will shrink. Newer, <a href="https://www.google.com/patents/US20150265508">easy-to-remove inks are being patented</a>, which may represent a healthier approach due to biodegradable ingredients, and a more predictable laser response. <a href="http://link.springer.com/article/10.1007/s10103-016-2001-0">Picosecond lasers</a> are also dramatically decreasing the number of sessions needed in select populations. </p>
<h2>Education is the key</h2>
<p>With such a large number considering tattoos at a young age, informing young people of the health and social risks could help them avoid tattoos they may come to regret. Adding <a href="http://teenstattoosandpiercings.com/">permanent body art education</a> to health classes could mitigate some of these mistakes and decrease later regret.</p><img src="https://counter.theconversation.com/content/67762/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Greg Hall, MD is the author of Teens, Tattoos, & Piercings: The health & social impact of permanent body art.</span></em></p>Tattoos often seem like a good idea in the moment, but tattoo regret is common. There is good reason, not the least of which is infection.Gregory L. Hall, Assistant Clinical Professor, Case Western Reserve UniversityLicensed as Creative Commons – attribution, no derivatives.