tag:theconversation.com,2011:/fr/topics/fructose-3493/articlesFructose – The Conversation2024-03-28T12:18:54Ztag:theconversation.com,2011:article/2232392024-03-28T12:18:54Z2024-03-28T12:18:54ZWhat is sugar and what would happen if I stopped eating it? A scientist explains<p>The world has declared a time-out on sugar consumption. The harmful link between disease and dietary sugar was recently outlined in a <a href="https://pubmed.ncbi.nlm.nih.gov/37019448/">comprehensive assessment</a> of published studies. </p>
<p>Recognising this link between widely consumed food and disease is essential in marshalling forces to <a href="https://www.who.int/tools/elena/interventions/free-sugars-adults-ncds">change harmful outcomes</a>. These include coronary heart disease, obesity, type 2 diabetes, tooth decay and some cancers. For over a decade, <a href="https://www.researchgate.net/profile/Grace-Jones-10#publications">my research</a> has focused on the mechanisms by which fructose intake plays into disease. </p>
<p>A growing number of African countries have joined the worldwide efforts to reduce sugar intake. For instance, in an attempt to address obesity, diabetes and other non-communicable diseases, South Africa introduced a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9597050/#:%7E:text=South%20Africa%20became%20the%20first,implemented%20on%201%20April%202018.&text=Referred%20to%20as%20the%20Health,billions%20of%20rands%20in%20revenues.">tax on sugar-sweetened drinks</a> in 2018. </p>
<p>It’s hard to avoid sugar when it’s become a normal part of diets and when we celebrate special times with sweet treats. But being more aware of what sugar is and how it can affect our health is the first step.</p>
<h2>What is sugar?</h2>
<p>Sugar is a class of naturally occurring sweet-tasting molecules found in fruits, vegetables, plants and the milk of mammals. It can be extracted from these natural sources and concentrated in processed foods. </p>
<p>The sweet-tasting molecules in sucrose (table sugar) are glucose and fructose. </p>
<p>Sucrose is a disaccharide. This is a molecule made of two simple sugars – glucose and fructose – in a 1:1 ratio and chemically bound. Sucrose is used in many processed foods.</p>
<p>High fructose corn syrup, also used in processed foods, is a mixture of the monosaccharides glucose and fructose. Usually the combination is 45% glucose and 55% fructose. </p>
<p>Sucrose and high fructose corn syrup are more concentrated in processed foods than in fruits and vegetables. </p>
<p>Both are considered added sugars when they are <a href="https://ift.onlinelibrary.wiley.com/doi/abs/10.1111/1541-4337.12151">added to foods and drinks</a>. Besides the sweet taste, they may be <a href="https://www.sciencedaily.com/releases/2015/08/150818131807.htm#:%7E:text=Sugar%20aids%20in%20the%20fermentation,reducing%20water%20activity%20in%20foods">added</a> for colour and texture, as a preservative or to aid fermentation. </p>
<p>There are other natural sugars found in the foods we eat. Lactose, or milk sugar, is a disaccharide made of two simple sugars – glucose and galactose – in a 1:1 ratio. It’s found in mammals’ milk and produced naturally to provide nutrition to offspring, and in other dairy products, such as cheese and ice cream. </p>
<p>Honey, made from nectar by honeybees, is primarily a mixture of glucose and fructose monosaccharides with some maltose, sucrose and other carbohydrates. Maltose, which is found in breakfast cereals and breads, is a disaccharide of two glucose molecules. </p>
<p>Naturally occurring sugars are made by plants, bees or mammals based on their needs. </p>
<p>The human body needs glucose as a fuel for every cell, especially brain cells. That’s one of the reasons why we need a stable blood glucose level throughout the day and night.</p>
<p>The way our bodies use fructose is different. It can be turned into glucose, used as fuel, or processed into fats, called triglycerides. Excessive fructose in our diets can lead to <a href="https://pubmed.ncbi.nlm.nih.gov/29408694/">increases</a> in blood triglycerides, liver fat, blood glucose, body mass index and insulin resistance (where the body cannot easily remove glucose from the bloodstream). </p>
<p>Increases in these markers can lead to an increased risk for metabolic dysfunction, type 2 diabetes and non-alcoholic fatty liver disease (or metabolic dysfunction-associated steatotic liver disease). </p>
<p>Because of the difference in how the body uses glucose and fructose, and evidence that a higher consumption of sugar leads to worse health outcomes, we must be mindful of the added sugar we eat.</p>
<h2>What would happen if we quit eating sugar?</h2>
<p>A group of scientists performed a study and published a set of research papers that detailed <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/oby.21371">exactly what happened</a> when over 40 children (aged eight to 18) stopped eating sugar and fructose for 10 days. The participants didn’t stop eating bread, hotdogs or snacks. They stopped eating fructose. These studies found <a href="https://pubmed.ncbi.nlm.nih.gov/28579536/">significant reductions</a> in:</p>
<ul>
<li><p>newly made triglycerides (or fats)</p></li>
<li><p>fasting blood glucose</p></li>
<li><p>blood pressure</p></li>
<li><p>fat stored on organs, including the liver</p></li>
<li><p>AST, which is a marker of liver function</p></li>
<li><p>insulin resistance, as their cells were better able to remove glucose from the bloodstream</p></li>
<li><p>body mass index.</p></li>
</ul>
<p>The participants also reported feeling better and were better behaved.</p>
<p>The World Health Organization has made <a href="https://iris.who.int/bitstream/handle/10665/149782/9789241549028_eng.pdf?sequence=1">recommendations</a> for adults and children to reduce their sugar intake to about 58 grams, or 14 teaspoons, per day or between 5% and 10% of total caloric intake. </p>
<p>This is not a lot of sugar. </p>
<p>Consider that a 300ml bottle of Coca-Cola or 240ml cup of sugarcane juice contain about <a href="https://www.coca-cola.com/ke/en/brands/brand-coca-cola/product-coca-cola-original#accordion-d588759a1d-item-8b5bb499cf">30 grams</a> of sugar. One piece of mandazi, a popular deep-fried Kenyan wheat snack, has about <a href="https://www.nutritionix.com/i/nutritionix/mandazi-1-small-piece-3-diameter/5c4f552f21b2c9e80f1748f2">4 grams</a> of sugar, or about 6% of the WHO’s recommended intake contained in each small piece.</p>
<h2>What can I do to lower my sugar intake to recommended levels?</h2>
<p>First, keep track of everything you eat during a typical day, what you eat, when you eat and how much you eat. Secondly, give yourself a star for the fresh vegetables and whole fruits you eat, and identify the foods that have added sugars. </p>
<p>Now, set an attainable goal that details one thing you can change to either:</p>
<p>1) increase the whole fruits or vegetables you eat or </p>
<p>2) decrease the amount of added sugar that you eat each day. </p>
<p>This way, you can be mindful of the added sugar you consume and adjust what you eat accordingly.</p><img src="https://counter.theconversation.com/content/223239/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Grace Marie Jones receives funding from The National Institutes of Health (US). </span></em></p>A higher consumption of sugar leads to worse health outcomes, so we need to be mindful of the added sugar we eat.Grace Marie Jones, Associate Professor, College of Osteopathic Medicine, Touro UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1841282022-08-22T12:26:15Z2022-08-22T12:26:15ZTwo surprising reasons behind the obesity epidemic: Too much salt, not enough water<figure><img src="https://images.theconversation.com/files/471724/original/file-20220629-12-h11vd4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3600%2C2398&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Salty french fries may taste good, but they just contribute to dehydration and obesity.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cropped-image-of-tempted-boy-holding-french-fries-royalty-free-image/660559557?adppopup=true">William Voon/EyeEm via Getty Images</a></span></figcaption></figure><p>Scientific studies and <a href="https://www.washingtonpost.com/health/what-percent-young-adults-obese/2021/12/03/b6010f98-5387-11ec-9267-17ae3bde2f26_story.html">media coverage</a> are rife <a href="https://doi.org/10.1002/oby.22073">with warnings</a> on how <a href="https://doi.org/10.31883/pjfns/110735">sugar</a>, <a href="https://doi.org/10.1111/jhn.12559">carbohydrates</a>, <a href="https://doi.org/10.3945/jn.111.153460">saturated fat</a> and <a href="https://www.hsph.harvard.edu/obesity-prevention-source/obesity-causes/physical-activity-and-obesity/">lack of exercise</a> contribute to obesity. And <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7721435/">tens of millions of Americans are still overweight or obese</a> in large part because of the classic Western diet and lifestyle. </p>
<p>As an <a href="https://drrichardjohnson.com/about/#">educator, researcher and professor of medicine</a>, I have <a href="https://drrichardjohnson.com/books/">spent more than 20 years</a> <a href="https://scholar.google.com/citations?user=dTgECeMAAAAJ&hl=en">investigating the causes of obesity</a>, as well as related conditions such as diabetes, high blood pressure and chronic kidney disease. </p>
<p>Throughout my many years of studying obesity and related health conditions, I’ve observed that relatively little is said about two significant pieces of this very complex puzzle: lack of hydration and excessive salt intake. Both are known to contribute to obesity. </p>
<h2>Lessons learned from a desert sand rat</h2>
<p>Nature provides a clue to the role these factors play with the desert sand rat <em>Psammomys obesus</em>, a half-pound rodent with a high-pitched squeak that lives in the salty marshes and deserts of Northern Africa. It survives, barely, by eating the stems of <em>Salicornia</em> – the glasswort – a plant that looks a bit like asparagus. </p>
<p>Although low in nutrients, the glasswort’s fleshy, succulent sap is filled with water that’s rich in salt, at concentrations as high as what’s found in seawater.</p>
<p>Recent studies <a href="https://doi.org/10.1073/pnas.1713837115">have provided new insights</a> into why the desert sand rat might crave the salty sap of glasswort. Although this has not yet been proven specifically in the sand rat, it is likely that a high-salt diet helps the sand rat convert the relatively low amount of carbohydrates it’s ingesting into fructose, a type of sugar that occurs naturally in fruits, honey and some vegetables.</p>
<p>This <a href="https://doi.org/10.1111/joim.12993">helps the animal survive</a> when food and fresh water are sparse. This is because fructose activates a “survival switch” that stimulates foraging, food intake and the storage of fat and carbohydrates that protect the animal from starvation.</p>
<p>However, when the rat is brought into captivity and given the common rodent diet of about 50% carbohydrates, it <a href="https://doi.org/10.1152/ajplegacy.1965.208.2.297">rapidly develops obesity and diabetes</a>. But if given fresh vegetables low in starchy carbohydrates, the rodent remains lean. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A desert sand rat, with prominent whiskers and a brown and white coat, takes a look outside its burrow." src="https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=433&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=433&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=433&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=544&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=544&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=544&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The desert sand rat, also known as the fat sand rat, is actually a gerbil. It’s found in Asia as well as Africa.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/fat-sand-rat-emerging-from-burrow-in-coastal-royalty-free-image/617548398?adppopup=true">Kristian Bell/Moment via Getty Images</a></span>
</figcaption>
</figure>
<p><a href="https://drrichardjohnson.com/books/">My research</a>, and the research of many other scientists over the decades, shows that many Americans unwittingly behave much like a captive desert sand rat, although few are in settings where food and water are limited. They are constantly activating the survival switch. </p>
<h2>Fructose and our diets</h2>
<p>As mentioned, fructose, a simple sugar, appears to have a key role in activating this survival switch that leads to fat production.</p>
<p>Small amounts of fructose, like that found in an individual fruit, are not the problem – rather it is excessive amounts of fructose that are problematic for human health. Most of us get our fructose from table sugar and high-fructose corn syrup. Intake of these two sugars <a href="https://www.usatoday.com/story/news/world/2014/03/05/five-percent-of-calories-should-be-from-sugar/6097623/">totals approximately 15% of calories</a> in the average American diet. </p>
<p>These sugars encourage people to eat more, which can lead to <a href="https://doi.org/10.1038/s41574-021-00627-6">weight gain, fat accumulation and prediabetes</a>. </p>
<p>Our bodies also make fructose on their own – and experimental studies suggest it may be enough to <a href="https://doi.org/10.1074/jbc.RA118.006158">trigger the development of obesity</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A spoonful of sugar, surrounded by sugar cubes, on a wooden table." src="https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=461&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=461&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=461&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=579&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=579&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=579&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Table sugar and high-fructose corn syrup are two of the culprits that can cause weight gain and obesity.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/sugar-spoon-on-wood-royalty-free-image/681197933?adppopup=true">ATU Images/The Image Bank via Getty Images</a></span>
</figcaption>
</figure>
<p>Since fructose is made from glucose, production of fructose increases when blood glucose levels are high. This process happens when we eat a lot of rice, cereal, potatoes and white bread; those are carbs that rapidly release glucose into the blood rapidly.</p>
<p>And notably, fructose production can also <a href="https://doi.org/10.1074/jbc.RA118.006158">be stimulated by dehydration</a>, which drives fat production. </p>
<h2>Fat provides water</h2>
<p>Fat has two major functions. The first one, which is well known, is to store calories for a later time when food is unavailable. </p>
<p>The other major but lesser-known function of fat <a href="https://doi.org/10.1681/ASN.2015121314">is to provide water</a>. </p>
<p>To be clear, fat does not contain water. But when fat breaks down, it generates water in the body. The amount produced is substantial, and roughly equivalent to the amount of fat burned. It’s so significant that some animals <a href="https://doi.org/10.1681/ASN.2015121314">rely on fat to provide water</a> during times when it’s not available. </p>
<p>Whales are but one example. While they drink some seawater, they get most of their water from the foods they eat. And when they go for extended periods without food, they get their water <a href="https://doi.org/10.1242/jeb.204.11.1831">primarily by metabolizing fat</a>. </p>
<h2>Hold the fries</h2>
<p>The role of dehydration as a contributor to obesity should not be underestimated. It commonly occurs after eating salty foods. Both dehydration and salt consumption lead to <a href="https://doi.org/10.1073/pnas.1713837115">the production of fructose and fat</a>. </p>
<p>This is why salty french fries are especially fattening. The salt causes a dehydration-like state that encourages the conversion of the starch in the french fry to fructose.</p>
<p>What’s more, studies show most people who are overweight or obese <a href="https://doi.org/10.1038/sj.ejcn.1602521">don’t drink enough water</a>. They are far more likely to be dehydrated than those who are lean. Their salt intake is also very high compared with lean people’s. </p>
<p>Research shows that people with obesity frequently <a href="https://doi.org/10.1038/ijo.2012.88">have high levels of vasopressin</a>, a hormone that helps the kidneys hold water to regulate urine volume. </p>
<p>But recent studies suggest vasopressin has another purpose, which is <a href="https://doi.org/10.1172/jci.insight.140848">to stimulate fat production</a>. </p>
<p>For someone at risk of dehydration or starvation, vasopressin may have a real survival benefit. But for those not at risk, vasopressin could drive most of the metabolic effects of excess fructose, like weight gain, fat accumulation, fatty liver and prediabetes. </p>
<h2>Drinking more water</h2>
<p>So does this mean drinking more water can help us lose weight? The medical community has <a href="https://www.nytimes.com/2021/09/17/well/live/how-much-water-should-I-drink.html">often scoffed at the assertion</a>. However, our research team found that giving mice more water slowed <a href="https://doi.org/10.1172/jci.insight.140848">weight gain and the development of prediabetes</a>, even when the mice had diets rich in sugar and fat. </p>
<p>There is also increasing evidence that <a href="https://doi.org/10.3390/nu14102070">most people drink too little water</a> in general, and increasing water intake may help people who are obese <a href="https://doi.org/10.1038/oby.2008.409">lose weight</a>. </p>
<p>That’s why I encourage drinking eight tall glasses of water a day. And eight is likely enough; don’t assume more is better. There have been cases of people drinking so much that “water intoxication” occurs. This is particularly a problem with people who have heart, kidney or liver conditions, as well as those who have had recent surgery or <a href="https://doi.org/10.1056/NEJMoa043901">are long-distance runners</a>. It’s always good to first check with your doctor about water intake. </p>
<p>For the desert sand rat, and for our ancestors who scavenged for food, a high-salt and limited-water diet made sense. But human beings no longer live that way. These simple measures – drinking more water and reducing salt intake – offer cheap, easy and healthy strategies that may prevent or treat obesity.</p><img src="https://counter.theconversation.com/content/184128/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Johnson is a Professor of Medicine at the University of Colorado Anschutz Medical Campus who has received funding from the National Institutes of Health, Veteran's Health Administration, and Department of Defense to understand the role of fructose metabolism in a variety of metabolic disorders. He also has equity with Colorado Research Partners LLC that is developing inhibitors of fructose metabolism. He is also author of Nature Wants Us to Be Fat (Benbella books, 2022) that discusses the science of fructose and its role in obesity and metabolic disorders.</span></em></p>Studies show that most people who are overweight or obese are also chronically dehydrated.Richard Johnson, Professor of Medicine, University of Colorado Anschutz Medical CampusLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1732142022-01-11T13:34:07Z2022-01-11T13:34:07ZHow does excess sugar affect the developing brain throughout childhood and adolescence? A neuroscientist who studies nutrition explains<figure><img src="https://images.theconversation.com/files/436595/original/file-20211209-15-n5wcwm.jpg?ixlib=rb-1.1.0&rect=0%2C37%2C6230%2C4091&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A diet high in sugary foods can affect brain development in children.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/assortment-of-products-with-high-sugar-level-royalty-free-image/1137312526?adppopup=true">carlosgaw/iStock via Getty Images Plus</a></span></figcaption></figure><p>Parents often stress about their kids’ sugar intake, but it can be hard to know <a href="https://theconversation.com/how-much-candy-do-americans-eat-in-a-whole-year-173956">how much is too much</a> – or what to do about it. </p>
<p>Glucose – a simple sugar that <a href="https://theconversation.com/whats-the-difference-between-sugar-other-natural-sweeteners-and-artificial-sweeteners-a-food-chemist-explains-sweet-science-172571">forms the basis of most carbohydrate-rich food</a> – is the primary source of energy for the brain. Healthy brains require a continuous source of energy and nutrients to fuel growth, learning and development. </p>
<p>However, that doesn’t mean extra consumption of sugar is good for the developing brain. In fact, too much sugar can actually be detrimental to the normal growth of the brain. </p>
<p><a href="https://www.binghamton.edu/decker/health-wellness-studies/profile.html?id=lina">I am a clinical nutritionist and a nutrition scientist with a neuroscience focus</a> whose <a href="https://scholar.google.com/citations?user=sOMbzQ0AAAAJ&hl=en">research revolves around</a> understanding the impact of diet and lifestyle on brain function and mental well-being. Preliminary results from my research indicate that consumption of sugary food is associated with mental distress – such as anxiety and depression – and disrupted sleep. </p>
<figure class="align-center ">
<img alt="A young girl eats a pink-glazed donut." src="https://images.theconversation.com/files/436767/original/file-20211209-13-8rbzw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/436767/original/file-20211209-13-8rbzw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/436767/original/file-20211209-13-8rbzw3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/436767/original/file-20211209-13-8rbzw3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/436767/original/file-20211209-13-8rbzw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/436767/original/file-20211209-13-8rbzw3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/436767/original/file-20211209-13-8rbzw3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Eating too many sugary foods can overstimulate the brain, leading to hyperactivity and mood swings.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/portrait-of-girl-eating-doughnut-jersey-city-new-royalty-free-image/492644977?adppopup=true">Jamie Grill via Getty Images</a></span>
</figcaption>
</figure>
<h2>Sources of sugar in kids’ diet</h2>
<p>Processed foods, such as donuts, sodas and sweetened cereals, often contain added sugars. Unfortunately, these foods tend to be easily accessible to children and teenagers – whether it be after sports games or at birthday parties. </p>
<p>Chemically <a href="https://www.hsph.harvard.edu/nutritionsource/processed-foods/">processed foods</a> are those that have been altered by adding components not naturally found in them. These foods often contain added sugars, preservatives, salts and trans fats – all aimed at increasing taste, texture or shelf life. </p>
<p>As a result, processed foods have a lower nutritional value than whole foods, such as fruits, vegetables and whole grains. One of the most common sweeteners in U.S. food products is high-fructose corn syrup, which contains not only glucose but another simple sugar called fructose. Too much fructose has been <a href="https://doi.org/10.1038/srep09589">associated with increased body fat</a>. High-fructose corn syrup is found in sodas and baked goods like muffins and donuts. </p>
<h2>Diet, brain and function</h2>
<p>Certain dietary components such as amino acids, which form the basis of proteins, act as precursors for brain chemicals. Amino acids also play important roles in mood, learning and cognitive functions.</p>
<p>Like car engines that require the proper fuel to run efficiently, brains also require an <a href="https://www.ncbi.nlm.nih.gov/books/NBK20414/">adequate diet for optimal functioning</a>. The <a href="https://www.livescience.com/29365-human-brain.html">brain is made up of</a> nerve cells, or neurons, and housekeeping cells, called glial cells. Although these two types of brain cells have different metabolic needs, glucose is the primary source of energy for both. </p>
<p>Despite the fact that the brain accounts for only 2% of human body weight, it requires <a href="https://doi.org/10.1073/pnas.172399499">about 20% of the human body’s energy needs</a> to perform all of its functions, including learning, memory and cognitive processes. Research suggests that this number is even higher in children <a href="https://doi.org/10.1097/MPG.0000000000001875">whose brains and bodies are developing rapidly</a>.</p>
<p>Brain function and growth are regulated by brain chemicals known as <a href="https://www.medicalnewstoday.com/articles/326649#key-types-of-neurotransmitters">neurotransmitters</a>, which should dictate <a href="https://doi.org/10.1016/S0166-2236(96)01028-4">the architecture of brain development</a>. Depending on the stage of brain growth, an <a href="https://www.verywellhealth.com/chemical-imbalance-5191365">imbalance of critical neurotransmitters</a> may cause a myriad of ailments, affecting learning, mood and behaviors. </p>
<p>Similarly, a low-quality or imbalanced diet, such as one high in processed sugar, can throw off the brain’s chemical equilibrium. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/lEXBxijQREo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Why are sugary foods so hard to resist? One reason is that sweets activate the brain’s reward system.</span></figcaption>
</figure>
<h2>Excess sugar puts the brain in overdrive</h2>
<p>Because glucose is the primary source of energy to the brain, too much sugar can put it into an overdrive mode. When the brain is overstimulated, it can lead to hyperactivity and mood swings. However, these behavioral changes are only the short-term consequences. Some evidence suggests that this brain hyperactivity in adolescents is linked to <a href="https://doi.org/10.3389/fnins.2021.670430">cognitive deficits in adulthood</a>. </p>
<p>Sugar also <a href="https://doi.org/10.1016/j.neubiorev.2007.04.019">has an addictive effect</a> because it stimulates neurons in the brain’s reward system, known as the limbic system. When activated, the limbic system generates high emotions such as pleasure, which <a href="https://www.healthline.com/nutrition/how-food-addiction-works">reinforces further sugar consumption</a>.</p>
<p>In addition, within the limbic system there is a tiny structure called the <a href="https://doi.org/10.1016/j.neuron.2017.09.013">amygdala</a>, which processes emotional information. Overactivation of the amygdala is associated with exaggerated emotions such as fear and anxiety. </p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>Research suggests that there is <a href="https://doi.org/10.1016/j.neubiorev.2019.05.021">a strong relationship</a> between high sugar consumption, altered behaviors and poor emotional regulation. Although sugar intake may boost mood momentarily, chronic sugar consumption has been linked with <a href="https://doi.org/10.1038/s41598-017-05649-7">increased risk of mental health problems</a>. </p>
<p>Studies in lab animals also suggest that <a href="https://doi.org/10.1038/s41398-021-01309-7">high consumption of sugar</a> hinders learning and memory. Interestingly, daily intake of <a href="https://doi.org/10.1038/s41398-021-01309-7">sugar-sweetened beverages</a> during teenage years is associated with worsening of performance on a learning and memory task during adulthood. The researchers of that study suggest that this impairment could be due to alterations in gut bacteria. </p>
<p>Considering the mounting body of evidence, the seemingly <a href="https://theconversation.com/a-taste-for-sweet-an-anthropologist-explains-the-evolutionary-origins-of-why-youre-programmed-to-love-sugar-173197">irresistible sweetness of sugar</a> can translate into a bitter outcome for the developing brain. </p>
<p></p><hr> <p></p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?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"></span>
</figcaption>
</figure>
<p><em>This article is part of a series examining sugar’s effects on human health and culture. <a href="https://theconversation.com/us/topics/sugar-2022-114641">Read the series at theconversation.com</a>.</em></p><img src="https://counter.theconversation.com/content/173214/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lina Begdache 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>Kids often crave processed sugary foods. But research shows that consuming too many treats during childhood and adolescence may lead to behavioral and emotional problems.Lina Begdache, Assistant Professor of Nutrition, Binghamton University, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/941982018-04-04T21:27:47Z2018-04-04T21:27:47ZHow NAFTA will make us fat if the U.S. has its way<figure><img src="https://images.theconversation.com/files/213028/original/file-20180403-189798-1ncastw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An obese Quebec man is seen in this photo. Canada is resisting U.S. attempts during NAFTA renegotiations to stop it from putting labels on processed foods to warn of their health risks. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Canada’s health went under a trade-related microscope recently in two parallel developments.</p>
<p>First, <a href="https://breakingthenews.net/canada-rejects-us-food-packaging-proposals-in-nafta-talks/news/details/42746515">Canada rejected a U.S. proposal</a> in the renegotiated NAFTA that would ban “front-of-pack” labelling of foods unhealthily high in salt, fat or sugar.</p>
<p>It’s a good thing it did. At the same time, a new study found that <a href="https://www.sciencedirect.com/science/article/pii/S074937971831554X">Canadians packed on a lot of pounds after signing a free-trade deal with the United States in 1989</a>. </p>
<p>Both developments speak to the importance of governments protecting their ability to regulate for public health purposes when negotiating trade treaties. </p>
<p>Let’s look at the new study first. </p>
<p>Using a robust “natural experiment” design, researchers looked at changes in what’s known as calorie availability in Canada after it signed the 1989 Canada–U.S. Free Trade Agreement, a deal that was the prototype for NAFTA a few years later, when Mexico joined. </p>
<p>“Calorie availability” is a measure <a href="http://www.fao.org/3/a-i4691e.pdf">used by the United Nations Food and Agriculture Organization</a> as a proxy for overall food consumption. Between 1989 and 2006, the study found that Canadians’ per capita daily calorie intake went up by 170, equivalent to an average weight gain of between 1.8 and 12.2 kilograms over those seven years. </p>
<p>Much of this increase was the result of a surge in imports of American processed foods and U.S. investment in the processed food industry in Canada, almost certainly contributing to the doubling in Canadian obesity rates over the same time period. </p>
<h2>No U.S. trade deal? No calorie surge!</h2>
<p>Countries in the OECD (the Organisation for Economic Co-operation and Development) that did not have free-trade deals with the U.S. recorded much lower increases in calorie availability. </p>
<p>Other studies have found similar unhealthy food outcomes when countries enter trade or investment deals with the U.S. Examples include <a href="http://globalizationandhealth.biomedcentral.com/articles/10.1186/s12992-015-0127-7">increased sugary soft-drink consumption in Vietnam</a> and <a href="http://www.cmaj.ca/content/189/26/E881">a spike in high-fructose corn syrup sweeteners in Canada </a>(adding an extra 42 calories per day) following NAFTA’s full implementation in 1998. </p>
<p>Which brings us to the present NAFTA renegotiation. </p>
<p>One of the ways public health officials are attempting to shift behaviour away from energy-dense and nutritionally poor foods is to use warning labels. </p>
<p>Chile, facing its own obesity epidemic, was the first country to legislate such warnings to go on the “front of the pack” where consumers can clearly see them, indicating with a simple and easy-to-understand black stop sign when foods are unhealthily high in sugar, fats, salt or calories. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/213214/original/file-20180404-189821-kaf7ep.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/213214/original/file-20180404-189821-kaf7ep.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=135&fit=crop&dpr=1 600w, https://images.theconversation.com/files/213214/original/file-20180404-189821-kaf7ep.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=135&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/213214/original/file-20180404-189821-kaf7ep.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=135&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/213214/original/file-20180404-189821-kaf7ep.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=170&fit=crop&dpr=1 754w, https://images.theconversation.com/files/213214/original/file-20180404-189821-kaf7ep.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=170&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/213214/original/file-20180404-189821-kaf7ep.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=170&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Labels seen on Chilean food products that are high-calorie or otherwise unhealthy.</span>
<span class="attribution"><span class="source">Creative Commons</span></span>
</figcaption>
</figure>
<p>The Chilean food industry fought this legislation for several years. Several countries, including the U.S. and, under a previous government, Canada, <a href="https://academic.oup.com/heapro/advance-article/doi/10.1093/heapro/daw109/2897774">challenged the regulations at the World Trade Organization (WTO)</a>, questioning the scientific evidence that such labels are necessary or suggesting consumer education campaigns instead. </p>
<p>These WTO challenges succeeded in delaying and weakening somewhat the new labelling rules, but Chile forged ahead in enacting its new law in 2016. Other countries facing similar obesity health challenges, such as Peru, Brazil and Mexico, looked on favourably.</p>
<h2>Canada wants to warn citizens too</h2>
<p>Then came Canada’s decision to consult on four different designs for its own front-of-pack labelling. </p>
<p>Although not as comprehensive as Chile’s labelling laws (which include calories, something Canada might want to consider given the new calorie availability study), Canada is poised to become the second high-income country to graphically warn its citizens about foods they should think twice about before consuming. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/213215/original/file-20180404-189798-5rhpf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/213215/original/file-20180404-189798-5rhpf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=84&fit=crop&dpr=1 600w, https://images.theconversation.com/files/213215/original/file-20180404-189798-5rhpf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=84&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/213215/original/file-20180404-189798-5rhpf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=84&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/213215/original/file-20180404-189798-5rhpf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=106&fit=crop&dpr=1 754w, https://images.theconversation.com/files/213215/original/file-20180404-189798-5rhpf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=106&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/213215/original/file-20180404-189798-5rhpf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=106&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Canada’s new health labels.</span>
<span class="attribution"><span class="source">Health Canada</span></span>
</figcaption>
</figure>
<p>American trade officials are already upset with Chile’s laws. The U.S. processed food industry instead promotes its own voluntary — and confusing — labelling scheme. </p>
<p>If Canada succeeds in its own new front-of-pack labelling initiative, this could incentivize other countries to follow suit, setting in motion a global cascade similar to what occurred with cigarette packaging: From simple warnings, to stomach-churning photos, to plain, nondescript packaging. </p>
<p>The extent of the opposition to Chile’s law suggests that the processed food industry is deeply fearful that such labels just might work, and that sales of their profitably unhealthy “foods” may start to fall. </p>
<p>It was not surprising, then, when U.S. Trade Representative Robert Lighthizer confirmed publicly last month the rumour that <a href="https://www.c-span.org/video/?c4720040/us-trade-policy-agenda&start=3040">the Trump administration wants Canada and Mexico to agree to ban front-of-pack labelling</a> in a renegotiated NAFTA, arguing that national food labelling is “protectionist.”</p>
<p>While national food labelling would pose additional costs to U.S. exporters shipping their packaged foods to countries adopting such rules, the only thing being protected by banning it would be the financial interests of the American processed food industry. </p>
<p>An international food labelling system would make things easier, but countries have so far been unable to agree on regulations that would protect the health and well-being of their citizens. And would we really want it to be one “made in America” anyway?</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/213039/original/file-20180403-189816-47oot1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/213039/original/file-20180403-189816-47oot1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/213039/original/file-20180403-189816-47oot1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/213039/original/file-20180403-189816-47oot1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/213039/original/file-20180403-189816-47oot1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/213039/original/file-20180403-189816-47oot1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/213039/original/file-20180403-189816-47oot1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Canada’s chief NAFTA negotiator, Steve Verheul, talks to reporters following a roundtable with labour leaders in Ottawa on March 28, 2018.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Sean Kilpatrick</span></span>
</figcaption>
</figure>
<p>So it was a relief to learn that, as news of the Trump administration’s efforts to bully Canada and Mexico into an unhealthy NAFTA submission went international, Canada’s chief NAFTA negotiator, Steve Verheul, publicly stated that <a href="https://breakingthenews.net/canada-rejects-us-food-packaging-proposals-in-nafta-talks/news/details/42746515">Canada will not agree to any such labelling ban</a>. </p>
<p>Fittingly, Verheul made his remarks on the same day as the study about the Canada-U.S. calorie-surging trade deal in 1989 was made public.</p>
<p>If Canada holds firm to this and resists any further threats of tariffs and arm-twisting by the U.S., we’ll be performing an important service for the rest of the world. </p>
<p>We’ll be signalling that the ability of governments to introduce new public health regulations should not, and will not, be traded away.</p><img src="https://counter.theconversation.com/content/94198/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ronald Labonte receives funding from Canadian Institutes of Health Research and the Canada Research Chairs Secretariat. </span></em></p>The U.S. is vehemently opposed to Canada’s intention to put labels on unhealthy processed foods. Here’s why Canada should continue to stand its ground during NAFTA renegotiations.Ronald Labonte, Professor and Canada Research Chair, L’Université d’Ottawa/University of OttawaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/899582018-03-08T02:45:07Z2018-03-08T02:45:07ZIf sugar is so bad for us, why is the sugar in fruit OK?<figure><img src="https://images.theconversation.com/files/209443/original/file-20180308-146697-nzrkvg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">All types of sugars will give us the same amount of calories, whether they are from fruit or soft drink.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/female-hand-holding-banana-on-blue-1040612479?src=Et-jPh8H_ZN8dtYHeL6XYQ-1-6">Shutterstock/Dulin</a></span></figcaption></figure><p><em>This is the third in a four-part series on sugar, which covers sugar-free diets, how the different types of sugars compare, and the links between sugar and disease. Catch up on the other instalments <a href="https://theconversation.com/au/topics/sugar-2207">here</a>.</em> </p>
<hr>
<p>We hear regularly from <a href="http://www.who.int/nutrition/publications/guidelines/sugars_intake/en/">health organisations and experts</a> that we should eat less sugar. But we’re also told we should eat more fruit. </p>
<p>All types of sugar will give us the same amount of calories, whether they are from fruit or soft drink. But the health risks of eating sugar are <a href="http://www.who.int/nutrition/publications/guidelines/sugars_intake/en/">related to consuming too many “free sugars” in the diet</a>, not from eating sugars that are naturally present in fruits or milk.</p>
<h2>Types of sugar in food</h2>
<p>Sugar in food and drinks comes in various forms. Sugar molecules are classified as monosaccharides (single sugar molecules such as glucose and fructose) and disaccharides (more complex structures such as sucrose and lactose). </p>
<p>Fruit contains natural sugars, which are a mix of sucrose, fructose and glucose. Many people have heard that sugar is bad, and think that this must also therefore apply to fruits.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/you-dont-need-to-quit-sugar-to-improve-your-health-92032">You don't need to quit sugar to improve your health</a>
</strong>
</em>
</p>
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<p>But <a href="https://www.ncbi.nlm.nih.gov/pubmed/23594708">fructose is only harmful in excess amounts</a>, and not when it comes from fruit. It would be incredibly difficult to consume excessive amounts of fructose by eating whole fruits. </p>
<p>It’s much easier to consume excess sugar from foods and drinks that contain “free sugars”. </p>
<p>Free sugars include these same sugars (fructose, glucose, sucrose), but in this case they have been removed from their naturally occurring source (rather than being eaten as natural parts of fruits, dairy products, and some vegetables and grains). This includes sugar that is added to food and drinks by food companies, cooks or consumers.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/209133/original/file-20180306-146666-10php5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/209133/original/file-20180306-146666-10php5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/209133/original/file-20180306-146666-10php5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/209133/original/file-20180306-146666-10php5o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/209133/original/file-20180306-146666-10php5o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/209133/original/file-20180306-146666-10php5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/209133/original/file-20180306-146666-10php5o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/209133/original/file-20180306-146666-10php5o.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">The source matters most.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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</figure>
<h2>Health risks come from free sugars, not fruits</h2>
<p><a href="http://www.who.int/nutrition/publications/guidelines/sugars_intake/en/">Evidence</a> shows that the health risks from sugars, such as tooth decay and unhealthy weight gain, are related to consuming too many free sugars in the diet, not from eating sugars that are naturally present in fruits or milk.</p>
<p>For this reason it is recommended that no more than <a href="http://www.who.int/nutrition/publications/guidelines/sugars_intake/en/">10% of your daily calories come from free sugars</a>. For the average adult, this is about 50g or only slightly more than the amount of sugar in a can of regular soft drink or soda. It’s estimated that Australians get around <a href="http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/4364.0.55.011%7E2011-12%7EMain%20Features%7EHow%20much%20sugar%20was%20consumed%3f%7E8">60% (65g) of their sugar intake</a> from free sugars. </p>
<p>Foods that are sources of free sugars, such as juices, soft drinks, biscuits and lollies, are often high in calories and have little other nutritional value. It is often easy to consume more of them compared with fresh fruit and they also may be replacing other nutritious foods in the diet.</p>
<p>Consider a bottle of fruit juice – you would have to eat six whole oranges to get the same amount of sugar you consume in the juice. And because the fruit is in juice form, it counts towards your daily limit of free sugars.</p>
<p>Calories from drinks that contain sugar often become an addition to the calories you are eating from food, which may lead to weight gain over time. </p>
<p>Eating large amounts of dried fruit is also not a good idea if you are limiting your sugar intake. Through the process of removing water from the fruit, nutrients are concentrated, such that dried apricots, for example, contain about six times as much sugar (40g per 100g) as fresh apricots (6g per 100g).</p>
<h2>We need to eat fruit</h2>
<p>Unlike many foods that are high in free sugars, fruits are packaged with lots of nutrients that help provide us with a balanced diet for good health. </p>
<p>For starters, fruit is an excellent source of fibre. An average banana will provide 20-25% (6g) of your recommended daily fibre intake. Getting enough fibre in the diet is important for <a href="https://www.wcrf.org/sites/default/files/Second-Expert-Report.pdf">protecting against bowel cancer</a>. There is clear room for improvement in our fibre intake – adults in many countries consume only about half of the <a href="https://www.nrv.gov.au/nutrients/dietary-fibre">recommended amount each day</a> (25g for Aussie women and 30g for Aussie men).</p>
<p>The fibre in fruit, which is often absent in many foods and drinks with free sugars, <a href="https://www.sciencedirect.com/science/article/pii/S019566630800620X#bib30">may also help to fill you up, which means you eat less</a> overall at a meal. It’s not clear exactly why this is, but it could be related to the volume of the food (especially compared with liquids) and the chewing involved. </p>
<p>Fruit is also a good source of other nutrients such as potassium, which <a href="https://www.nrv.gov.au/nutrients/potassium">can help lower blood pressure</a>, and flavonoids, <a href="https://link.springer.com/article/10.1007%2Fs11883-013-0368-y">which may reduce</a> your risk of heart disease. </p>
<p><a href="http://www.bmj.com/content/349/bmj.g4490">There is evidence</a> that eating whole fruits (alone and in combination with vegetables) <a href="http://www.bmj.com/content/349/bmj.g4490">reduces your chances</a> of dying from cancer, obesity and heart disease.</p>
<p>Despite this, <a href="http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/4364.0.55.001%7E2014-15%7EMain%20Features%7EDaily%20intake%20of%20fruit%20and%20vegetables%7E28">only about 50% of Australians</a> eat at least two pieces of fruit per day. </p>
<p>Most national dietary guidelines encourage eating fruits and vegetables, with an emphasis on the vegetables. To try and eat your <a href="https://www.eatforhealth.gov.au/food-essentials/five-food-groups/fruit">recommended two pieces of fruit per day</a> remember that a piece could be a banana, apple or orange, or two smaller fruits like plums or apricots, or a cup of grapes or berries. </p>
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Read more:
<a href="https://theconversation.com/food-as-medicine-why-do-we-need-to-eat-so-many-vegetables-and-what-does-a-serve-actually-look-like-76149">Food as medicine: why do we need to eat so many vegetables and what does a serve actually look like?</a>
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<p>When it comes to other sources of sugars, try to choose foods that have little or no sugar listed in the ingredient list, and drink water instead of sugary beverages when you are thirsty.</p><img src="https://counter.theconversation.com/content/89958/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kacie Dickinson receives funding as an Endeavour Research Fellow from Australian Government Department of Education and Training and The Foundation for High Blood Pressure Research.</span></em></p><p class="fine-print"><em><span>As part of her PhD studies, Jodi Bernstein has received funding as a Fellow in the CIHR Collaborative Training Program for Public Health Policy, the CIHR Strategic Training Program in Population Intervention for Chronic Disease Prevention, and currently receives funding from an Ontario Graduate Scholarship. Jodi is also a co-investigator on a CIHR Sugars and Health Operating Grant and a Centre for Child Nutrition and Health Public Policy Collaborative Grant.</span></em></p>We often hear that we need to reduce our sugar intake. But don’t skimp on the fruit – eating whole fruit (not juice) is much healthier.Kacie Dickinson, Accredited Practising Dietitian; Lecturer in Nutrition and Dietetics, Flinders UniversityJodi Bernstein, PhD Candidate in Nutritional Sciences, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/816082017-09-20T02:13:57Z2017-09-20T02:13:57ZHealth Check: what’s better for you, fresh, dried or frozen fruit?<figure><img src="https://images.theconversation.com/files/182698/original/file-20170821-20193-1uoeoeh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Frozen, dried and freeze-dried fruit are certainly convenient. But are they as good for you as fresh fruit?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/474666319?size=medium_jpg">from www.shutterstock.com</a></span></figcaption></figure><p>“Eat more fruit and vegetables” is one of the most common recommendations we hear when we’re <a href="http://healthywa.wa.gov.au/Articles/F_I/Go-for-2-and-5">encouraged to eat healthily</a>. But when it comes to eating more fruit, we get mixed messages about how healthy fruit really is.</p>
<p>Some say its sugar content means fruit isn’t as healthy as many experts suggest.</p>
<p>Others suggest fruit is healthy as its sugars are natural and are contained in the fruit’s <a href="http://www.huffingtonpost.com/2013/06/29/fruit-sugar-versus-white-sugar_n_3497795.html">cells</a>. It’s thought we eat less of sugar contained in fibrous cells as it is more filling; we also absorb it more slowly than “free sugars” found in sugary drinks and processed foods.</p>
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<strong>
Read more:
<a href="https://theconversation.com/we-know-too-much-sugar-is-bad-for-us-but-do-different-sugars-have-different-health-effects-78921">We know too much sugar is bad for us, but do different sugars have different health effects?</a>
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<p>Then there’s the range of fruit products you can buy – including traditional dried fruits and the newer freeze-dried products.</p>
<p>So, when it comes to eating healthily, which fruit is best? And how do these fruit products compare?</p>
<h2>What’s in fruit?</h2>
<p>The idea that fruit is good for you is largely based on the fact that many fruits have a low energy (calorie) content and are packed with nutrients. Nutrients include vitamins, minerals, fibre and bioactive nutrients (often pigment compounds known as polyphenols and carotenoids).</p>
<p>Fruit also contains sugar, and the content can vary considerably. Some are very low in sugar, like <a href="https://ndb.nal.usda.gov/ndb/foods/show/99691?manu=&fgcd=&ds=">cranberries</a> (3.5% sugar) and <a href="https://ndb.nal.usda.gov/ndb/foods/show/147143?manu=&fgcd=&ds=">blackberries</a> (1.5%). </p>
<p>But some tropical fruit contain surprisingly high levels. These include <a href="https://ndb.nal.usda.gov/ndb/foods/show/170641?fgcd=&manu=&lfacet=&format=&count=&max=50&offset=&sort=default&order=asc&qlookup=fresh+mango&ds=&qt=&qp=&qa=&qn=&q=&ing=">mango</a> (14% sugar) and <a href="https://ndb.nal.usda.gov/ndb/foods/show/2249?fg=&manu=&lfacet=&format=&count=&max=50&offset=&sort=default&order=asc&qlookup=09144&ds=&qt=&qp=&qa=&qn=&q=&ing=">jackfruit</a> (19%).</p>
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Read more:
<a href="https://theconversation.com/you-say-tomato-why-some-fruits-are-forever-doomed-to-be-called-veggies-62099">You say tomato... why some fruits are forever doomed to be called veggies</a>
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<p>The type of sugar in fruit can also vary according to the type of fruit and also how <a href="https://theconversation.com/health-check-which-fruits-are-healthier-and-in-what-form-60182">ripe it is</a>. Generally, the most common sugar in fruit is fructose, typically making up <a href="http://www.huffingtonpost.com/2013/06/29/fruit-sugar-versus-white-sugar_n_3497795.html">40-55%</a> of the sugar in most fruit. Sucrose (normal table sugar) makes up most of the rest. </p>
<p>While some people say fructose is worse for you than other sugars, there is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3708747/pdf/1743-7075-10-45.pdf">limited</a> evidence for this.</p>
<h2>How does freezing affect fruit?</h2>
<p>Freezing tends to involve minimal processing, with only brief heat treatment before freezing to stop enzymes breaking down the fruit that would otherwise lead to spoilage and flavour changes. </p>
<p>Freezing generally is a good way to <a href="http://ucce.ucdavis.edu/files/datastore/234-779.pdf">preserve nutrients</a> compared to other methods like canning and refrigeration. This is mainly linked to the relatively short period of heat treatment used to <a href="http://www.eatright.org/resource/homefoodsafety/four-steps/refrigerate/blanch-before-you-freeze">blanch</a> food before freezing compared to longer heat treatments for canning.</p>
<p>Thawing should not lead to significant nutrient loss. However, the effect of ice crystals damaging cells during freezing soft fruit can lead to the fruit turning to a mush and then water soluble vitamins and minerals leaking out. </p>
<h2>How does drying affect fruit?</h2>
<p>Drying (losing water) concentrates the fruit’s sugar dramatically. For example, apricot sugar levels rise from <a href="https://ndb.nal.usda.gov/ndb/foods/show/2140?fgcd=&man=&lfacet=&count=&max=&sort=&qlookup=&offset=&format=Full&new=&measureby=">9.5%</a> when fresh to <a href="https://ndb.nal.usda.gov/ndb/foods/show/136206?fgcd=&manu=&lfacet=&format=&count=&max=50&offset=&sort=default&order=asc&qlookup=dried+apricots&ds=&qt=&qp=&qa=&qn=&q=&ing=">54.2%</a> when dried. </p>
<p>This is why some have described dried fruits as <a href="http://time.com/4082532/dried-fruit-prunes-sugar-raisins/">like sugar bombs</a>. Although the World Health Organisation does <a href="http://www.who.int/bulletin/volumes/92/11/14-031114.pdf">not classify dried fruit</a> as something we should limit in the diet.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/184473/original/file-20170904-17915-tdgub1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/184473/original/file-20170904-17915-tdgub1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/184473/original/file-20170904-17915-tdgub1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=370&fit=crop&dpr=1 600w, https://images.theconversation.com/files/184473/original/file-20170904-17915-tdgub1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=370&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/184473/original/file-20170904-17915-tdgub1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=370&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/184473/original/file-20170904-17915-tdgub1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=464&fit=crop&dpr=1 754w, https://images.theconversation.com/files/184473/original/file-20170904-17915-tdgub1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=464&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/184473/original/file-20170904-17915-tdgub1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=464&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">Dried fruit, like these dried apricots, contain higher sugar levels than their fresh equivalent.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/671242849?src=-JcVFH8fp9K-tsRiUupMcg-1-45&size=medium_jpg">from www.shutterstock.com</a></span>
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<p>Dried fruit can also be six times higher in energy than their fresh equivalents, due to a concentration effect through the removal of water. So, if you are trying to watch your weight, it would be sensible to watch your serve sizes of dried fruits. </p>
<p>But it’s not all bad news for dried fruit. Drying increases levels of some vitamins and minerals, again through the effect of concentrating the nutrients when water is lost. This means a 30g serve of dried apricots can <a href="http://www.nutritionaustralia.org/national/resource/iron">contain over 5% the daily recommended intake of iron</a>; you would need to eat 175g of fresh apricots to get the same amount.</p>
<h2>How about freeze-drying?</h2>
<p>Freeze-drying involves first freezing a fruit and then placing it in a vacuum under very low pressures. Low pressure causes ice crystals to rapidly sublime, turning them straight from <a href="https://www.spscientific.com/freeze-drying-lyophilization-basics/">solid ice into water vapour</a>. This process removes water much more efficiently than traditional drying.</p>
<p>Effectively, the fruit’s water content is reduced but the fruit’s structure is maintained. This makes this method of preserving food particularly suited to soft fruit, like raspberries and strawberries, <a href="http://www.foodnavigator.com/Market-Trends/Healthy-snacking-trend-boosts-sugar-free-fruit-ingredients">which are low in sugar</a>.</p>
<p>Freeze-drying is said to be one of the fastest growing trend in food, with sales of freeze-dried fruit forecast to reach <a href="http://www.refrigeratedfrozenfood.com/articles/91744-study-global-freeze-dried-market-to-reach-665b-by-2021">US$66.5 billion</a> by 2021.</p>
<p>While the public perceives freeze-dried fruit as a healthier alternative to candied fruit and possibly dried fruit, freeze-dried fruit has a much higher sugar content than its fresh equivalent. </p>
<p>And as freeze-drying is a more efficient way to remove water than traditional drying, it can mean per 100g, freeze-dried fruit can contain more sugar than dried fruit.</p>
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<a href="https://images.theconversation.com/files/184475/original/file-20170904-17971-g8igc7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/184475/original/file-20170904-17971-g8igc7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/184475/original/file-20170904-17971-g8igc7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=310&fit=crop&dpr=1 600w, https://images.theconversation.com/files/184475/original/file-20170904-17971-g8igc7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=310&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/184475/original/file-20170904-17971-g8igc7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=310&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/184475/original/file-20170904-17971-g8igc7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=389&fit=crop&dpr=1 754w, https://images.theconversation.com/files/184475/original/file-20170904-17971-g8igc7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=389&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/184475/original/file-20170904-17971-g8igc7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=389&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">These freeze dried strawberries contain 14 times as much sugar as fresh ones.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/616077626?src=_pihaGC1KI4dd_q9X79hwQ-1-27&size=medium_jpg">from www.shutterstock.com</a></span>
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<p>So, fresh strawberries contain <a href="https://ndb.nal.usda.gov/ndb/foods/show/2385?fgcd=&manu=&lfacet=&format=&count=&max=50&offset=&sort=default&order=asc&qlookup=strawberry&ds=Standard+Reference&qt=&qp=&qa=&qn=&q=&ing=">4.9% sugar</a>. But freeze-dried strawberries contain <a href="https://ndb.nal.usda.gov/ndb/foods/show/129997?manu=&fgcd=&ds=Standard%20Reference">71% sugar</a>, a 14-fold increase. That’s a sugar content similar to some lollies.</p>
<p>Like freezing, freeze-drying helps to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3155377/">preserve nutrients</a>. However, we will still see losses in these, especially vitamin C.</p>
<p>But as freeze-dried fruits contain less water than fresh fruits, you could end up eating more pieces of them than fresh, which means more nutrients (but also more energy and sugar). </p>
<h2>So, what’s the bottom line?</h2>
<p>The bottom line is to try and <a href="https://www.csiro.au/en/News/News-releases/2017/Diets-Lacking-in-Fruit-and-Vegetables">eat more fruit</a>, in the least processed form possible, ideally fresh.</p>
<p>And if you choose dried or freeze-dried fruit for convenience, these contain more concentrated sugar than the original fresh product.</p><img src="https://counter.theconversation.com/content/81608/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duane Mellor is affiliated with the British Dietetic Association, where he is currently Chair of the Communications and Marketing Board. </span></em></p><p class="fine-print"><em><span>Ekavi Georgousopoulou, Nenad Naumovski, and Senaka Ranadheera do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Dried and frozen fruit contain more sugar than their fresh equivalents. So, why do we think they’re healthy?Duane Mellor, Senior Lecturer, Coventry UniversityEkavi Georgousopoulou, Research associate, University of CanberraNenad Naumovski, Asistant Professor in Food Science and Human Nutrition, University of CanberraSenaka Ranadheera, Early Career Research Fellow, Advanced Food Systems Research Unit, College of Health and Biomedicine, Victoria UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/789212017-06-09T05:01:06Z2017-06-09T05:01:06ZWe know too much sugar is bad for us, but do different sugars have different health effects?<figure><img src="https://images.theconversation.com/files/172880/original/file-20170608-29563-1dmhqa8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The type of sugar in popular soft drinks varies from country to country even if the brand name is the same.</span> <span class="attribution"><span class="source">from shutterstock.com</span></span></figcaption></figure><p>Our recent article published in the <a href="https://www.mja.com.au/journal/2017/206/10/sugar-content-soft-drinks-australia-europe-and-united-states">Medical Journal of Australia</a> found that Australian and European soft drinks contained higher concentrations of glucose, and less fructose, than soft drinks in the United States. The total glucose concentration of Australian soft drinks was on average 22% higher than in US formulations.</p>
<p>We compared the composition of sugars in four popular, globally marketed brands – Coca-Cola, Fanta, Sprite and Pepsi – using samples from Australia, Europe and the US. While the total sugar concentration did not differ significantly between brands or geographical location, there were differences between countries in the concentrations of particular sugars, even when drinks were marketed under the same trade name.</p>
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<a href="https://images.theconversation.com/files/172874/original/file-20170608-29563-pnrhx8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/172874/original/file-20170608-29563-pnrhx8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/172874/original/file-20170608-29563-pnrhx8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=913&fit=crop&dpr=1 600w, https://images.theconversation.com/files/172874/original/file-20170608-29563-pnrhx8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=913&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/172874/original/file-20170608-29563-pnrhx8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=913&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/172874/original/file-20170608-29563-pnrhx8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1148&fit=crop&dpr=1 754w, https://images.theconversation.com/files/172874/original/file-20170608-29563-pnrhx8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1148&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/172874/original/file-20170608-29563-pnrhx8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1148&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">Sucrose is made up of one glucose molecule and one fructose molecule.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
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<p>Whether these differences have distinct effects on long-term health is currently unclear. Certainly, over-consumption of either glucose or fructose will contribute to <a href="http://ajcn.nutrition.org/content/98/4/1084.full.pdf">weight gain</a>, which is associated with a host of health conditions such as <a href="https://www.ncbi.nlm.nih.gov/pubmed/15328324">type 2 diabetes</a> and <a href="http://circ.ahajournals.org/content/121/11/1356">heart disease</a>. And because the body metabolises glucose and fructose in different ways, their effects may differ.</p>
<h2>Sucrose, glucose and fructose</h2>
<p>Soft drinks, as they are referred to in Australia, or “sodas” in the US and “fizzy drinks” in the UK, are non-alcoholic, carbonated, sugar-sweetened beverages. <a href="http://www.coca-colacompany.com/cs/tccc-yir2012/operating_groups.html">Australia ranks seventh out of the top ten countries</a> for soft drink sales per capita.</p>
<p>Sugars are the chief ingredient in soft drinks and include glucose, fructose and sucrose. The source of sugars in popular soft drinks varies between global regions. This is because sugars are sourced from different crops in different areas of the world. </p>
<p>Soft drinks in Australia are primarily sweetened with sucrose from sugar cane. Sucrose, often referred to as “table sugar”, is composed of one glucose molecule and one fructose molecule joined by chemical bonds. This means equal amounts of glucose and fructose are released into the bloodstream when sucrose is digested.</p>
<p>Overseas, soft drinks are sweetened with sucrose-rich sugar beet (Europe) or high-fructose corn syrup (US). High-fructose corn syrup is also made up of glucose and fructose, but contains a higher fructose-to-glucose ratio than sucrose.</p>
<h2>Do they have different health impacts?</h2>
<p>Fructose over-consumption is <a href="https://www.ncbi.nlm.nih.gov/pubmed/26055949">known to contribute</a> to <a href="http://christinecronau.com/wp-content/uploads/2011/10/nrgastro.2010.41.pdf">fatty liver disease</a>. Fatty liver disease affects <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/liver-fatty-liver-disease">about one in ten people</a> in the West. Non-alcoholic fatty liver disease is the leading cause of liver disease.</p>
<p>Some researchers have suggested too much fructose in the diet can harm the liver in a similar fashion to alcohol. However, this concern is related to <em>added</em> fructose in the diet, not natural sources. Natural sources of fructose, such as fruit, honey and some vegetables, are not generally over-consumed and provide other important nutrients, such as dietary fibre and vitamins. So, fruit does not generally pose a risk for fatty liver disease.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/173054/original/file-20170609-1721-1lht3p3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/173054/original/file-20170609-1721-1lht3p3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/173054/original/file-20170609-1721-1lht3p3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/173054/original/file-20170609-1721-1lht3p3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/173054/original/file-20170609-1721-1lht3p3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/173054/original/file-20170609-1721-1lht3p3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/173054/original/file-20170609-1721-1lht3p3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/173054/original/file-20170609-1721-1lht3p3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&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">Natural sources of fructose, such as fruit, are generally not over-consumed.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
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</figure>
<p>High glucose consumption rapidly elevates blood glucose and insulin. This may affect <a href="https://www.ncbi.nlm.nih.gov/pubmed/15451897">brain function</a>, including <a href="https://lipidworld.biomedcentral.com/articles/10.1186/1476-511X-13-195">mood and fatigue</a>. Because high blood glucose is <a href="https://www.ncbi.nlm.nih.gov/pubmed/16919548">linked to diabetes</a>, consumption of high-glucose drinks may also raise the risk of diabetes and cardiovascular (heart) disease. </p>
<p>All soft drinks are considered energy-dense, nutrient-poor and bad for health. However, one of the inherent challenges in the field has been an inability to determine the actual dose of glucose or fructose in these drinks. </p>
<p>Studies that follow people over time, and link soft drink consumption to adverse health effects, are complicated by not knowing whether individuals in these studies are simply eating too many energy-rich foods, and whether soft drink consumption coincides with other poor health behaviours. So, further research is required to determine whether soft drinks containing different concentrations of fructose and glucose are associated with differing health risks. </p>
<h2>Soft drink policies</h2>
<p>There is still much to learn about the differences in composition of sugars and patterns of soft drink intake between countries. A small number of countries, including <a href="https://www.theguardian.com/society/2017/feb/22/mexico-sugar-tax-lower-consumption-second-year-running">Mexico</a> and <a href="http://www.bbc.com/news/world-europe-38767941">France</a>, have already implemented taxation on soft drinks. It remains to be determined whether these actions reduce the incidence of obesity, diabetes and heart diseases.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/173056/original/file-20170609-32402-pssvkt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/173056/original/file-20170609-32402-pssvkt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/173056/original/file-20170609-32402-pssvkt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/173056/original/file-20170609-32402-pssvkt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/173056/original/file-20170609-32402-pssvkt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/173056/original/file-20170609-32402-pssvkt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/173056/original/file-20170609-32402-pssvkt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/173056/original/file-20170609-32402-pssvkt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&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">Over-consumption of any kind of sugar leads to weight gain.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>Australian policymakers are yet to take action to reduce soft drink consumption. A range of intervention strategies have been considered, including banning sugary soft drinks in schools and hospitals, taxation, and regulating beverage marketing. </p>
<p>The <a href="http://www.abc.net.au/news/2017-06-08/sugary-drinks-to-be-phased-out-of-nsw-health-facilities/8599820">New South Wales Health Department</a> has just announced sugary drinks will be phased out of vending machines, cafes and catering services in the state’s health facilities by December. This is a great move. Importantly, we must continue to increase public awareness of the adverse health effects of sugary soft drinks.</p><img src="https://counter.theconversation.com/content/78921/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bronwyn Kingwell receives funding from the National Health and Medical Research Council of Australia.</span></em></p><p class="fine-print"><em><span>Pia Varsamis and Robyn Larsen do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A recent study found Australian soft drinks had higher concentrations of glucose than US soft drinks, which had more fructose. Does this mean Australian drinks are worse for health than US drinks?Bronwyn Kingwell, Head, Metabolic and Vascular Physiology NHMRC, Senior Principal Research Fellow, Baker Heart and Diabetes InstitutePia Varsamis, PhD Student, Metabolic and Vascular Physiology, Baker Heart and Diabetes InstituteRobyn Larsen, Postdoctural Research Fellow in Nutritional Biochemistry, Baker Heart and Diabetes InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/744312017-04-03T10:54:22Z2017-04-03T10:54:22ZFructose: friend or foe?<figure><img src="https://images.theconversation.com/files/163545/original/image-20170402-27256-10zpmf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fruit - a natural source of fructose.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/252338818?src=HPr9BPug3f2ut8X60HhaPQ-1-1&size=medium_jpg">leonori/Shutterstock.com</a></span></figcaption></figure><p>Fructose has been getting a bad rap lately. Although consuming too much can be bad for your health, those who exercise seem to be protected against some of fructose’s negative health effects. And growing <a href="http://www.mdpi.com/2072-6643/9/4/344/htm">evidence</a> suggests that fructose can help athletes recover after exercise. </p>
<p><a href="http://www.fao.org/docrep/W8079E/W8079E00.htm">Fructose and glucose</a> are the two carbohydrates that make up table sugar. Although <a href="http://ajcn.nutrition.org/content/76/5/911.full">fructose has largely been blamed</a> for many of the negative health effects of sugar, it has some useful roles in the body.</p>
<p>Most of the glucose we consume <a href="http://www.jci.org/articles/view/111938">ends up in our muscles</a> where it is either stored in a form called <a href="http://ajpendo.physiology.org/content/311/3/E543.long">glycogen</a> or burned as a fuel. But fructose is mainly metabolised by <a href="http://physrev.physiology.org/content/90/1/23.long">the liver</a> because muscle cannot easily use fructose as a fuel, and this special metabolism is thought to lead to some of its negative health effects.</p>
<p>The <a href="http://physrev.physiology.org/content/90/1/23.long">liver converts fructose</a> into other useful substances, such as carbohydrates (glucose or lactate) or fat, which are then delivered to various parts of the body via the bloodstream, to be used as fuel. But if more glucose and fats enter the bloodstream than are removed by muscles and other tissues, it can lead to a build up in the bloodstream. </p>
<p>High levels of blood <a href="https://cardiab.biomedcentral.com/articles/10.1186/1475-2840-11-76">glucose</a> and <a href="https://jamanetwork.com/journals/jama/fullarticle/10.1001/jama.298.3.299">fats</a> are associated with an increased risk of heart disease, stroke and type 2 diabetes. But the increase in blood-fat levels, seen with high fructose intake, is still considered to be within the <a href="http://link.springer.com/article/10.1007%2Fs11906-016-0652-7">normal range</a>. Whether the small rises in blood fats with high fructose intake can truly result in an increased risk of disease is <a href="http://link.springer.com/article/10.1007%2Fs11906-016-0652-7">not yet certain</a>.</p>
<p>An increase in blood-fat levels also depends on how physically active you are. If you exercise every day, consuming huge amounts of fructose – comparable to 50 teaspoons of table sugar or more than five cans of soft drink per day – <a href="http://diabetes.diabetesjournals.org/content/62/7/2259.long">does not seem to influence blood-fat levels</a>. So, if you have a sweet tooth, exercise is advisable.</p>
<p>For athletes, fructose may even play a beneficial role in the diet. Athletes who perform in endurance sports, such as marathons, triathlons and cycling, may have multiple training sessions each day. This means that they often need to be at their physical best on more than one occasion within a 24-hour period. The main factor limiting these athletes is their bodily stores of carbohydrates as glycogen.</p>
<h2>Opening ‘doors’</h2>
<p>Glycogen is a molecule that is stored in the muscles and is <a href="http://onlinelibrary.wiley.com/doi/10.1111/sms.12599/abstract;jsessionid=10AB2E8C9F054B2F87CB36ECADE7D34B.f03t02?systemMessage=Wiley+Online+Library+will+be+unavailable+on+Saturday+25th+March+from+07%3A00+GMT+%2F+03%3A00+EDT+%2F+15%3A00+SGT+for+4+hours+for+essential+maintenance.++Apologies+for+the+inconvenience.">vital for performing intense exercise</a> since it can be quickly broken down into glucose and used as fuel. The <a href="http://ajpendo.physiology.org/content/311/3/E543.long">liver also stores glycogen</a> which serves as a critical source of glucose to stabilise blood-sugar levels when they become low.</p>
<p>When athletes train heavily or compete, it is important they replace any used glycogen stores between bouts of exercise to enable optimal performance in later events. They also need to get a lot of carbohydrate, in the form of glucose and fructose, into their bloodstream quickly during and after exercise, so that their liver and muscles can use it as fuel.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/160911/original/image-20170315-5354-8tvay0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/160911/original/image-20170315-5354-8tvay0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/160911/original/image-20170315-5354-8tvay0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/160911/original/image-20170315-5354-8tvay0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/160911/original/image-20170315-5354-8tvay0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/160911/original/image-20170315-5354-8tvay0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/160911/original/image-20170315-5354-8tvay0.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">Fructose-glucose mixtures are best for athletes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/athletes-taking-break-after-training-drinking-458352388?src=3MufXD6H_ZVaLF04A_HRnQ-1-30">pixelrain/Shutterstock</a></span>
</figcaption>
</figure>
<p>The main route for glucose absorption from the gut is through a transporter called <a href="http://www.mdpi.com/2072-6643/9/4/344/htm">SGLT1</a> - a protein that acts like a door, helping glucose go from the gut to the bloodstream. SGLT1 is thought to have a maximum capacity for glucose transport because it can only transport around one gram of glucose per minute. Fructose, however, can be transported into the bloodstream using a different “door”, called GLUT5. By using both routes, rather than just SGLT1, athletes can <a href="http://www.mdpi.com/2072-6643/9/2/167">increase the amount of ingested carbohydrate</a> the body can use during exercise. </p>
<p>The rapid absorption of fructose-glucose mixtures and special handling of fructose in the liver are the two main reasons that fructose can also help to speed up recovery after exercise. <a href="http://jap.physiology.org/content/120/11/1328.long">We recently found</a> that when cyclists drank sports drinks containing both fructose and glucose after exercise, they accelerated the recovery of their liver glycogen stores. It almost doubled this rate of recovery compared with glucose-only drinks, when the same total amount of carbohydrate was consumed. </p>
<p>Athletes often need to consume lots of carbohydrate to fuel their exercise. The amount of carbohydrate they can consume during a race is almost never enough to prevent their stores of glycogen from <a href="http://ajpendo.physiology.org/content/309/12/E1032.long">depleting</a>. This is because the ability of the gut to digest and <a href="http://www.mdpi.com/2072-6643/9/4/344/htm">absorb the carbohydrate is limited</a>. </p>
<p>The muscles can use this glucose quicker than we can digest and absorb carbohydrates. As a result, the gut is pushed to its maximum capacity and athletes can suffer from stomach problems, such as bloating. One of the noticeable advantages for athletes is that when they consume fructose-glucose mixtures in sports drinks and gels they experience fewer <a href="http://ajpendo.physiology.org/content/309/12/E1032.long">stomach problems</a> compared with glucose-only sports drinks. The rapid transport of fructose means less sugar is left in the stomach and intestine during exercise, which is usually the main cause of stomach complaints. </p>
<p>So, although fructose may have its downfalls, these are possibly only a problem for people who are inactive. Even modest amounts of exercise may be enough to prevent some of the negative health effects. For the endurance athlete, not only is fructose unlikely to cause harm, there are even some useful effects for athletic performance.</p><img src="https://counter.theconversation.com/content/74431/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span><a href="mailto:j.t.gonzalez@bath.ac.uk">j.t.gonzalez@bath.ac.uk</a> has received funding from The Rank Prize Funds, The Physiological Society, The European Society for Clinical Nutrition, The Medical Research Council, Kenniscentrum Suiker & Voeding and Arla Foods Ingredients. He has consulted to Lucozade Ribena Suntory.</span></em></p>Fructose may be a food ‘baddie’ if you’re a couch potato. But for sportspeople, it’s a godsend.Javier T. Gonzalez, Lecturer (Assistant Professor), University of BathLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/732582017-02-23T14:03:24Z2017-02-23T14:03:24ZThe human brain makes fructose, researchers discover – here’s why that might be a big deal<figure><img src="https://images.theconversation.com/files/157539/original/image-20170220-15892-1cxna2m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fructose factory.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/425709700?src=aPSVg551_PmaSrRc4TFqPA-1-49&size=medium_jpg">Jezper/Shutterstock.com</a></span></figcaption></figure><p>Researchers at Yale University have <a href="http://insight.jci.org/articles/view/90508">discovered</a> that the brain is capable of making fructose – a simple sugar, usually found in fruit, vegetables and honey.</p>
<p>Not all sugars are equal. Glucose is a simple sugar that provides energy for the cells in your body. Fructose has a less important physiological role and has been repeatedly linked to the development of <a href="http://ajcn.nutrition.org/content/86/4/899.short">obesity and type 2 diabetes</a>. When there is excess glucose the processes that break it down can become saturated, so the body converts glucose into fructose instead, using a process known as the “polyol pathway”, a chemical reaction involved in <a href="https://www.ncbi.nlm.nih.gov/pubmed/18224243">diabetic complications</a>. The researchers at Yale reported in the journal, JCI Insight, that the brain uses the polyol pathway to produce fructose in the brain. </p>
<p>Unlike glucose, which can be metabolised throughout the body, fructose is normally metabolised almost completely <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3533803/">in the liver</a> and also in semen where it <a href="http://onlinelibrary.wiley.com/doi/10.1002/j.1939-4640.1980.tb00035.x/abstract">produces energy for sperm</a>. Most fructose produced by this pathway is thought to stay inside the cells that make it, as fructose levels in the blood are usually extremely low. These low circulating levels make it unlikely that fructose made in this way reaches the brain in significant amounts, and yet some studies have previously identified very <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0128582">high levels of fructose</a> in the central nervous system (the brain and spinal cord). </p>
<p>Importantly, research has shown that exposure to fructose can significantly <a href="http://www.ebiomedicine.com/article/S2352-3964%2816%2930143-8/abstract">alter the expression</a> of hundreds of genes in the brain, including genes that control metabolism, cell communication, inflammation and brain function. This suggests that fructose is likely to alter brain function.</p>
<h2>What it means</h2>
<p>The brain relies heavily on glucose to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3900881/">fuel its activities</a>. There is evidence that those with diabetes have a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2797942/">higher risk of dementia or cognitive decline</a>, suggesting that exposure to excess glucose is also bad for the brain. Until now, the mechanism for this has been poorly understood. </p>
<p>The team at Yale, which published this most recent research, used a brain scanning technology known as as magnetic resonance spectroscopy to measure the levels of glucose and fructose in the brains of eight healthy participants. What they showed was that after just 20 minutes of a glucose infusion into the blood, fructose levels in the brain markedly increased, and at much higher levels than in the blood. </p>
<p>All eight volunteers included in the study saw similar effects, but those that had the highest levels of glucose in the brain also had the highest levels of fructose. This provides the first ever conclusive evidence that the human brain is able to take excess glucose and rapidly convert it into fructose. Production of fructose in the human brain may therefore actually be a mechanism by which high levels of glucose alter brain function. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/157561/original/image-20170220-15914-ws8uuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/157561/original/image-20170220-15914-ws8uuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=493&fit=crop&dpr=1 600w, https://images.theconversation.com/files/157561/original/image-20170220-15914-ws8uuu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=493&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/157561/original/image-20170220-15914-ws8uuu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=493&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/157561/original/image-20170220-15914-ws8uuu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=619&fit=crop&dpr=1 754w, https://images.theconversation.com/files/157561/original/image-20170220-15914-ws8uuu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=619&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/157561/original/image-20170220-15914-ws8uuu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=619&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">High-fructose corn syrup is increasingly used in junk food.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/116741284?src=B75GxXz5urHySa3V77fpGQ-1-4&size=medium_jpg">Nitr/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>The findings of this study are very important. The consumption of fructose has greatly increased over the last five decades, due largely to the development of high-fructose corn syrup, a commercial sweetening agent that contains high amounts of free fructose. Consumption of fructose-rich diets have rightly come under attack as the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429636/">health implications become more clear</a>, but little focus on how glucose can be converted to fructose exists. </p>
<p>We currently have epidemic levels of <a href="https://www.diabetes.org.uk/Type-2-diabetes/">type 2 diabetes</a> in many parts of the world, a disease in which elevated blood glucose levels are seen. The data presented by the team at Yale suggest that in poorly controlled diabetics, whose blood glucose can rise and stay elevated for hours at a time, fructose will likely be rapidly produced in significant amounts in the brain and this could provide a mechanism for <a href="https://www.sciencedaily.com/releases/2015/07/150708160528.htm">changes in the brain</a> seen in type 2 diabetes. The population of poorly controlled diabetics is <a href="http://www.ajmc.com/journals/issue/2013/2013-1-vol19-n6/population-health-approach-for-diabetic-patients-with-poor-a1c-control">growing annually</a> making this an urgent problem.</p>
<p>This data is very exciting but does need to be approached with some caution. As only eight subjects were included in the study, it is difficult to apply the findings to larger populations. It would be interesting to repeat the experiment in people who have diabetes, to show if this effect also occurs due to normal fluctuations in blood-glucose levels. Regardless, this study changes the way we think about how the brain uses sugar and may lead to changes in how we target neurological complications of diabetes.</p><img src="https://counter.theconversation.com/content/73258/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Brown 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>The discovery by researchers at Yale University that the brain is capable of converting glucose into fructose may lead to changes in how we target neurological complications in diabetes.James Brown, Lecturer in Biology and Biomedical Science, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/497882015-10-27T19:43:18Z2015-10-27T19:43:18ZSugar isn’t just empty, fattening calories – it’s making us sick<figure><img src="https://images.theconversation.com/files/99753/original/image-20151026-18435-11ee0q4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Don't add sugar.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-116939734/stock-photo-wooden-bowl-of-sugar-with-metal-spoon.html?src=JQV6o_KbozN-HPe3TJY8Mg-1-64">Sugar bowl via www.shutterstock.com</a></span></figcaption></figure><p>Children are manifesting increased rates of adult diseases like <a href="http://www.ncbi.nlm.nih.gov/pubmed/15175438">hypertension or high triglycerides</a>. And they are getting diseases that used to be unheard of in children, like <a href="http://dx.doi.org/10.1111/nyas.12030">Type 2 diabetes and fatty liver disease</a>. So why is this happening?</p>
<p>Everyone assumes this is the result of the obesity epidemic – too many calories in, too few out. Children and adults are getting fat, so they’re getting sick. And it is generally assumed that no one specific food causes it, because “a calorie is a calorie”.</p>
<p>I’ve been studying the role that <a href="http://www.uctv.tv/shows/Sugar-The-Bitter-Truth-16717">sugar</a> plays in contributing to chronic disease for years, and my research group at the University of California, San Francisco has just published <a href="http://dx.doi.org/10.1002/oby.21371">research</a> in the journal Obesity that challenges this assumption. If calories come from sugar, they just aren’t the same.</p>
<h2>Diabetes is increasing faster than obesity</h2>
<p>It’s clear that the cause of rising rates of health conditions like Type 2 diabetes isn’t as simple as people just eating too many calories.</p>
<p>Obesity is increasing globally at 1% per year, while diabetes is increasing globally at <a href="http://dx.doi.org/10.1126/science.1257099">4% per year</a>. If diabetes were just a subset of obesity, how can you explain its more rapid increase? </p>
<p>And certain countries are obese without being diabetic (such as Iceland, Mongolia and Micronesia), while other countries are <a href="http://dx.doi.org/10.1371/journal.pone.0057873">diabetic without being obese</a> (India, Pakistan and China, for instance). Twelve percent of people in China have diabetes, but the obesity rate <a href="http://dx.doi.org/10.1016/S2213-8587(14)70144-5">is much lower</a>. The US is the fattest nation on Earth and our diabetes prevalence is <a href="http://www.diabetes.org/diabetes-basics/statistics/">9.3%</a>. </p>
<p>While 80% of the obese population in the US <a href="http://diabetes.diabetesjournals.org/content/53/3/585.full.pdf">is metabolically ill</a> (meaning they have conditions like <a href="http://www.ncbi.nlm.nih.gov/pubmed/14988241">diabetes</a>, hypertension, lipid problems and <a href="http://dx.doi.org/10.1016/j.jacc.2011.04.047">heart disease</a>), 20% is not. Conversely, 40% of the normal weight population <a href="http://dx.doi.org/10.1016/j.jacc.2011.04.047">has metabolic syndrome</a>. </p>
<p>If normal weight people have these conditions, how then are they related to obesity? Indeed, we now know that obesity is a marker <a href="http://dx.doi.org/10.1542/peds.2011-2912">rather than a cause</a> for these diseases. </p>
<p>Epidemiological studies have found a correlation between added sugar consumption and health conditions like <a href="http://circ.ahajournals.org/content/120/11/1011.abstract">cardiovascular disease</a>. So could cutting excess sugar out of our diets reverse metabolic syndrome? </p>
<h2>What happens when you stop feeding kids added sugar?</h2>
<p>Our group at UCSF <a href="http://dx.doi.org/10.1002/oby.21371">studied</a> 43 Latino and African-American children with obesity and metabolic syndrome over a 10-day period. We started by assessing their metabolic status – insulin and glucose levels, as well as blood fats and other markers for disease, like lactate and free fatty acids – on their home diet. </p>
<p>For the next nine days, each child ate an individual tailored diet. We catered their meals to provide same number of calories and protein and fat content as their usual home diet. We gave them the same percentage of carbohydrate, but we substituted starch for sugar. The big difference: this special diet had <em>no</em> added sugar. This means their diet had no sugar from sugarcane or high fructose corn syrup. The kids consumed foods such as fruits and other whole foods that naturally contain some sugar. These foods also have fiber, which reduces the rate of sugar absorption, so they don’t affect the body the same way that added sugar does. </p>
<p>We took chicken teriyaki out. We put turkey hot dogs in. We took sweetened yogurt out. We put baked potato chips in. We took donuts out. We put bagels in. We gave them unhealthy processed food, just with no added sugar. Each child was given a scale to take home, and if their weight was declining, we made them eat more. Then we studied them again. </p>
<p>The children had eaten the same number of calories and had not lost any weight, and yet every aspect of their metabolic health improved. With added sugar cut out of their diet for 10 days, blood pressure, triglycerides, low-density lipoprotein (LDL, or “bad cholesterol”), insulin sensitivity and glucose tolerance all improved. And remember, we weren’t giving them just leafy greens and tofu – we fed the kids processed foods, just ones without sugar.</p>
<p>Further studies are needed to see if this will also work in adults, and if the benefits are short-term or long-term. </p>
<h2>Sugar is like alcohol</h2>
<p>This study demonstrates that a calorie is <em>not</em> a calorie, and that sugar is a primary contributor to metabolic syndrome, unrelated to calories or weight gain. By removing added sugar, we improved metabolic health. </p>
<p>Sugar may not be the only contributor to chronic disease, but it is far and away the easiest one to avoid. Kids could improve their metabolic health – even while continuing to eat processed food – just by dumping the sugar. Can you imagine how much healthier they’d be if they ate real food?</p>
<p>The naysayers will say, “But sugar is natural. Sugar has been with us for thousands of years. Sugar is food, and how can food be toxic?” </p>
<p>Webster’s Dictionary <a href="http://www.merriam-webster.com/dictionary/food">defines food</a> as:</p>
<blockquote>
<p>material consisting essentially of protein, carbohydrate, and fat used in the body of an organism to sustain growth, repair, and vital processes and to furnish energy.</p>
</blockquote>
<p>Sugar by itself furnishes energy, and that’s about it. In that sense, sugar is like alcohol. It’s got calories, but it’s not nutrition. There’s no biochemical reaction that requires it. And at high doses, alcohol can fry your liver.</p>
<p>Same with sugar. Fructose, the sweet molecule in sugar, contains calories that you can burn for energy, but it’s not nutrition, because there’s no biochemical reaction that requires it. In excess, it can fry your liver, just <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3649103/">like alcohol</a>. And this makes sense, because where do you get alcohol from? Fermentation of sugar.</p>
<p>Too much sugar causes diabetes, heart disease, fatty liver disease and <a href="http://www.ncbi.nlm.nih.gov/pubmed/26261186">tooth decay</a>. When consumed in excess, it’s a <a href="http://www.nytimes.com/2011/04/17/magazine/mag-17Sugar-t.html">toxin</a>. And it’s addictive – <a href="http://www.ncbi.nlm.nih.gov/pubmed/23493539">just like alcohol</a>. That’s why children are getting the diseases of alcohol – Type 2 diabetes and fatty liver disease – without alcohol. But our research suggests we could turn this around in 10 days – if we chose to.</p><img src="https://counter.theconversation.com/content/49788/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Lustig 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>Researchers have found that cutting sugar out of kids’ diets can improve their blood pressure, cholesterol readings and other markers of metabolic health.Robert Lustig, Professor of Pediatrics, University of California, San FranciscoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/194952013-10-28T06:30:07Z2013-10-28T06:30:07ZEU Fructose ruling means dodgy health claims are easier to make<figure><img src="https://images.theconversation.com/files/33810/original/ss8j7jsx-1382699876.jpg?ixlib=rb-1.1.0&rect=269%2C1%2C754%2C485&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fructose is associated with US obesity rise but Europe allows health claims.</span> <span class="attribution"><span class="source">Macz_out</span></span></figcaption></figure><p>An EU decision to allow health claims to be made about fructose has angered obesity experts <a href="http://www.theguardian.com/society/2013/oct/17/obesity-experts-appalled-eu-fructose-health-claim-approval">who blame the fruit sugar</a> for rising obesity levels in the US. The decision allows food and drink manufacturers <a href="http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32013R0536:EN:NOT">to claim</a> the “consumption of foods containing fructose leads to a lower blood glucose rise compared to foods containing sucrose or glucose”, where at least 30% of other sugars have been replaced by fructose.</p>
<p>Last December, the EU <a href="http://www.efsa.europa.eu/en/topics/topic/nutrition.htm">restricted food health claims</a> on products to those that had been scientifically substantiated and officially authorised. The fructose claim was allowed because it has a low glycemic index (GI), but there are serious concerns because this <a href="https://theconversation.com/fructose-health-claims-ignores-evidence-of-harm-19476">doesn’t necessarily</a> make it healthy and also whether a health claim should be allowed at all when we should be consuming less sugar — glucose, sucrose or fructose — in our diet.</p>
<h2>Warnings from the science community</h2>
<p>The European Food Safety Authority (EFSA), which advised on the decision, actually <a href="http://www.efsa.europa.eu/en/efsajournal/pub/2223.htm">sounded a note of caution</a> in May 2011. It pointed out that high intakes of fructose could lead to complications such as dyslipidaemia (a higher amount of lipids such as cholesterol in the blood), insulin resistance and an increase in visceral fat: the internal fatty deposits that can accumulate around organs (rather the fat you can pinch under your skin). </p>
<p>Robert Lustig, an American endocrinologist, <a href="http://www.theguardian.com/commentisfree/2013/oct/21/fructose-poison-sugar-industry-pseudoscience">went further</a>. He argued it was pseudoscience to find a health benefit from reducing blood glucose when increasing fructose in the blood directly contributed to heart disease and diabetes and was associated <a href="https://theconversation.com/fructose-health-claims-ignores-evidence-of-harm-19476">with other</a> serious health problems.</p>
<h2>The ‘halo effect’</h2>
<p>A major fear is the so-called halo effect, where a product that is marked as healthy, or has at least some health claims, leads consumers to believe it is a wholly healthy product. The drafters of the <a href="http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32006R1924:EN:NOT">2006 EU Regulation</a> on health and nutrition claims clearly shared this concern and wanted to avoid a situation where “nutrition or health claims mask the overall nutritional status of a food product, which could mislead consumers when trying to make healthy choices in the context of a balanced diet”. For this reason, the regulation required the EC to establish “specific nutrient profiles which food or certain categories of food must comply with in order to bear nutrition or health claims”. </p>
<p>These are the same tools that are used in the UK to determine when food and drink is too high in fat, sugar or salt, to be advertised to some children on TV. <a href="https://www.gov.uk/government/publications/the-nutrient-profiling-model">Nutrient profiles</a> drawn up by the Food Standards Agency, weigh up the amount of fat, sugar and salt in foods against the good nutrients like vitamins and minerals.</p>
<p>But although there was a January 2009 deadline for the EC to produce nutrient profiles according to the regulation, no profiles have been developed to date. This failure means that the EC also has no option to restrict claims on unhealthy foods - it must either authorise or refuse them.</p>
<h2>Refuse or defer</h2>
<p>In the case of fructose, the better path would have been to refuse the fructose claim, or at least defer a decision pending further evidence. Not only would this respect the intention of the regulation to avoid mixed messages but it would also have invoked the “<a href="http://ec.europa.eu/food/food/foodlaw/precautionary/index_en.htm">precautionary principle</a>”, which applies when a danger has been identified but there is no strong evidence of the precise risk involved, and which comes into play in issues of health and consumer protection. </p>
<p>In this case there is mounting scientific evidence of <a href="http://www.nature.com/nature/journal/v502/n7470/full/502181a.html">harm from fructose</a> consumption and uncertainty about a potential increase in consumption from manufacturers re-formulating food and drinks with fructose and promoting them using a health claim. It has been pointed out elsewhere that fructose manufacturers <a href="http://www.nutraingredients.com/Industry/Sweet-sales-future-for-fructose-products">clearly expect</a> a surge in sales.</p>
<p>Instead, the commission chose to authorise the fructose claim rather than taking the approach <a href="http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32013R0536:EN:NOT">used for other claims</a> that involved refusing authorisation or deferring a decision to avoid confusing the consumer (for example, over conflicting national dietary advice on sugars and a potential health claim relating to carbohydrates) or misleading them (because a salt claim relied on compositional levels that were uncertain and therefore may not have been beneficial).</p>
<p>Perhaps this is “incompetence or collusion” as Lustig suggests, or maybe it is one bad decision in the absence of evidence on the effect of a claim.</p>
<p>It could also be that this is the first of several narrow, “technical” health claims that could be applied to products that are high in fat, salt or sugars, as industry gets smarter about the system and the process of authorisation - in which case it is time the European Commission revisited the spirit of the regulation to make sure we avoid these mixed messages. Unfortunately this may not be possible until it fulfils its obligation to develop a set of nutrient profiles that can actually be used to guide health and nutrition claims.</p><img src="https://counter.theconversation.com/content/19495/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 organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An EU decision to allow health claims to be made about fructose has angered obesity experts who blame the fruit sugar for rising obesity levels in the US. The decision allows food and drink manufacturers…Colin Mitchell, Researcher, University of OxfordMike Rayner, Director of the BHF Health Promotion Research Group, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/194762013-10-24T19:44:18Z2013-10-24T19:44:18ZFructose health claims ignores evidence of harm<figure><img src="https://images.theconversation.com/files/33670/original/fx56xf3s-1382586428.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The European food agency has decided to allow health claims for products containing fructose.</span> <span class="attribution"><span class="source">Broken Haiku/Flickr</span></span></figcaption></figure><p>The European Food and Safety Agency (EFSA) has just approved health claims for fructose-sweetened products, in a move that has <a href="http://www.theguardian.com/society/2013/oct/17/obesity-experts-appalled-eu-fructose-health-claim-approval">astonished scientists around the world</a>.</p>
<p>Food and drink manufacturers can now claim that their products are healthier if they replace at least 30% of their glucose or sucrose with fructose.</p>
<p>The rationale provided by the EFSA for the decision is that fructose has a low glycemic index (GI). The glycemic index of a particular food is a measure of the rise in blood glucose levels in response to 50 grams of carbohydrate in that food. </p>
<p>This glucose response drives the subsequent insulin response, and insulin is the major hormone driving fat accumulation. That’s the link with obesity.</p>
<p>But it’s not really as simple as that. Just because a food has a low glycemic index doesn’t mean it’s healthy or that you can eat as much of it as you want.</p>
<p>Processed foods containing fat (such as ice-cream, chocolate, and potato crisps) have a low glycemic index because fat slows gastric emptying (the rate at which food enters the small intestine from the stomach). But most of us would recognise they are not the ideal foods to eat when you want to lose weight.</p>
<p>Fructose has a low glycemic index, which is not surprising since it’s not glucose (recall that glycemic index measures the rise in blood glucose levels). But that doesn’t mean it’s not potentially problematic.</p>
<p>Fructose and glucose are handled very differently by the body. Whereas glucose is used by most tissues as a source of energy, fructose is taken up almost entirely by the liver. </p>
<p>When we are eating more than we need, fructose is converted very efficiently by the liver into fat. Just like excessive alcohol consumption, this can cause fatty liver (non-alcoholic fatty liver), which is now very common among people who are overweight and obese. </p>
<p>Left unchecked, fatty liver can lead to cirrhosis and liver failure. It also contributes to weight gain generally. </p>
<p>Excess consumption of glucose (in the form of starchy foods) can certainly contribute to weight gain, but not fatty liver. </p>
<p>Excessive consumption of fructose (more so than glucose) exacerbates insulin resistance and the metabolic syndrome – and thereby greatly increases the risk of type 2 diabetes and cardiovascular disease.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/33672/original/pqdb9d6t-1382587851.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/33672/original/pqdb9d6t-1382587851.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=430&fit=crop&dpr=1 600w, https://images.theconversation.com/files/33672/original/pqdb9d6t-1382587851.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=430&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/33672/original/pqdb9d6t-1382587851.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=430&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/33672/original/pqdb9d6t-1382587851.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=540&fit=crop&dpr=1 754w, https://images.theconversation.com/files/33672/original/pqdb9d6t-1382587851.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=540&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/33672/original/pqdb9d6t-1382587851.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=540&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ice-cream’s low glycemic index doesn’t make it a healthy product.</span>
<span class="attribution"><span class="source">Cascadian Farm/Flickr</span></span>
</figcaption>
</figure>
<p>It’s important to note that dietary fructose is not a problem if you’re lean and fit, and not over-eating. Under those circumstances, the fructose will be metabolised as an energy source.</p>
<p>The major sources of glucose are starches (polymers of glucose) and sucrose (which is comprised of one molecule of glucose and one of fructose). </p>
<p>Our major source of fructose in Australia is sucrose. In the United States, high fructose corn syrup is now a major source. </p>
<p>While there’s also fructose in fruit, it’s in a diluted form and present with a range of other healthy nutrients and fibre. And health claims are overwhelming applied to highly-processed foods (think of the last time you saw a health claim on an apple). </p>
<p>But why would the processed food industry want to be able to make health claims for fructose?</p>
<p>Fructose is much sweeter than glucose and significantly sweeter than sucrose. The food industry has conducted very sophisticated research on what stimulates food consumption (the “bliss point”), and found that, together with fat and salt, sweetness is one of the <a href="http://michaelmossbooks.com/">major drivers of excess food intake</a>.</p>
<p>So, sweetness is very good for business.</p>
<p>And interestingly, when we drink calories, particularly watery calories as in soft drinks or alcohol (as opposed to soup), our body does not recognise them as such; it’s as if we were drinking water. </p>
<p>Caloric drinks are particularly problematic because <a href="http://www.ncbi.nlm.nih.gov/pubmed/10878689">they’re added on</a> to what we voluntarily eat. </p>
<p>The European Union’s approach to food regulation, then, is very reductionist. The EFSA has taken one short-term impact of a food component (the glycemic index) to justify a health claim for fructose, and ignored all the science that indicates its adverse impacts on long-term health in relation to over-consumption, weight gain, diabetes, heart disease and liver disease.</p>
<p>This is yet another victory for the powerful processed food and beverage lobbies over advocates for public health.</p><img src="https://counter.theconversation.com/content/19476/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kerin O'Dea receives funding from the National Health and Medical Research Council and the Australian Research Council.
</span></em></p>The European Food and Safety Agency (EFSA) has just approved health claims for fructose-sweetened products, in a move that has astonished scientists around the world. Food and drink manufacturers can now…Kerin O'Dea, Professor of Population Health and Nutrition, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/74242012-08-13T20:43:11Z2012-08-13T20:43:11ZWhat role does fructose have in weight gain?<figure><img src="https://images.theconversation.com/files/13926/original/5vg48fr5-1344232858.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The main sources of fructose in the typical western diet are processed foods and beverages.</span> <span class="attribution"><span class="source">Boris/Flickr</span></span></figcaption></figure><p>Sucrose or sugar has two components – glucose and fructose. Glucose is present in virtually all naturally-occurring sweet foods and also exists as starch (although in a different chemical form, so it doesn’t taste sweet). Fructose occurs naturally in fruit, honey and some vegetables. But the main sources of fructose in the typical western diet are processed foods and beverages that contain added sugar derived from sugar cane or sugar beet. </p>
<p>In some countries, notably the United States, a sweetener known as high-fructose corn syrup (HFCS) is used to sweeten many processed foods, but HFCS is not a common source of fructose in the Australian diet.</p>
<p>Ingested fructose is treated differently to glucose following digestion and absorption into the body. While glucose is readily transported around the body to where it’s needed as an energy source, fructose is metabolised almost exclusively <a href="http://www.ncbi.nlm.nih.gov/pubmed/20086073">in the liver</a>. </p>
<p><a href="http://www.ncbi.nlm.nih.gov/pubmed/16778579">Many studies</a> have shown that feeding animals (such as rats and mice) high-fructose diets leads to increased body weight, higher levels of blood <a href="http://en.wikipedia.org/wiki/Lipid">lipids</a> and blood pressure, and other components of metabolic syndrome (a condition that pre-disposes to several diseases, including heart disease and type 2 diabetes). </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/13922/original/2jpd3j3z-1344232525.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/13922/original/2jpd3j3z-1344232525.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/13922/original/2jpd3j3z-1344232525.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/13922/original/2jpd3j3z-1344232525.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/13922/original/2jpd3j3z-1344232525.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/13922/original/2jpd3j3z-1344232525.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/13922/original/2jpd3j3z-1344232525.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fructose occurs naturally in fruit, honey, some vegetables and in sugar, which is derived from sugar cane or sugar beet.</span>
<span class="attribution"><span class="source">tinyfroglet/Flickr</span></span>
</figcaption>
</figure>
<p>There’s also good evidence that fructose is <a href="http://www.ncbi.nlm.nih.gov/pubmed/17617461">addictive in rats</a>, perhaps in a similar way to cocaine. As a result, there’s speculation that the fructose component of sugar may be one of the major driving forces behind the current epidemics of obesity and type 2 diabetes in humans.</p>
<p>The proponent of this concept with the highest profile is a US professor of paediatrics, Dr Robert Lustig, who argues that fructose is “alcohol without the ‘buzz’”, that is, it’s addictive in people, toxic and <a href="http://www.visiond.com/ASN_2012/Sun_Sym_Fructose/Lustig.html">equally harmful as alcohol</a>. </p>
<p>Lustig hypothesises that consumption of added fructose (that is, other than that occurring in fruit) at virtually any level promotes metabolic syndrome, leading to obesity, type 2 diabetes and increased risk of heart disease. As a result, he argues, fructose consumption is the cause of the obesity epidemic, and 35 million deaths occur annually worldwide because of it.</p>
<p>But how strong is the evidence for this “fructose hypothesis”, and how much credence should we give to the claim that fructose is the sole cause of most of our health problems?</p>
<p>Although it would be wonderful if there were a simple solution (such as avoiding all sources of added fructose) to the epidemics of obesity and type 2 diabetes that are sweeping the world, the evidence implicating fructose as the sole cause is weak, to say the least. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/13928/original/gmp4brf4-1344233039.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/13928/original/gmp4brf4-1344233039.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/13928/original/gmp4brf4-1344233039.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/13928/original/gmp4brf4-1344233039.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/13928/original/gmp4brf4-1344233039.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/13928/original/gmp4brf4-1344233039.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/13928/original/gmp4brf4-1344233039.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sucrose or sugar has two components – glucose and fructose.</span>
<span class="attribution"><span class="source">Uwe Hermann</span></span>
</figcaption>
</figure>
<p>There’s overwhelming support for the belief that high intakes of fructose are harmful to human health, but the evidence is, at best, equivocal that low or even moderate intakes of fructose are harmful, in either <a href="http://www.ncbi.nlm.nih.gov/pubmed/20047139">normal weight</a> people or in those who are <a href="http://www.tandfonline.com/doi/abs/10.1080/10408398.2010.512990">overweight or obese.</a></p>
<p>One of the problems with the fructose hypothesis is that much of the evidence comes from animal studies, especially those involving rats. But people are not rats, and it’s not appropriate to assume that similar effects will be seen in humans. Animal studies can only allow working hypotheses to be proposed, hypotheses that must then be subjected to rigorous testing.</p>
<p>In relation to the likelihood of sucrose (and therefore fructose) addiction occurring in humans, for instance, a review <a href="http://www.ncbi.nlm.nih.gov/pubmed/20056521">published in 2009</a> concluded there was “no support from the human literature for the hypothesis that sucrose may be physically addictive”, despite strong evidence for addiction in rats and mice.</p>
<p>Another effect that’s been claimed for fructose is that it’s less satiating than glucose, that is, fructose doesn’t make you feel as full, so you overeat. But, as applies to most of the claimed adverse effects of fructose on human health, the evidence for this is, at best, equivocal. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/13931/original/4vr77my5-1344233298.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/13931/original/4vr77my5-1344233298.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=902&fit=crop&dpr=1 600w, https://images.theconversation.com/files/13931/original/4vr77my5-1344233298.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=902&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/13931/original/4vr77my5-1344233298.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=902&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/13931/original/4vr77my5-1344233298.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1134&fit=crop&dpr=1 754w, https://images.theconversation.com/files/13931/original/4vr77my5-1344233298.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1134&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/13931/original/4vr77my5-1344233298.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1134&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The consumption of fructose in liquid form is associated with higher energy intake and increased body weight.</span>
<span class="attribution"><span class="source">Brad Herman</span></span>
</figcaption>
</figure>
<p>One 2009 review found that fructose was <a href="http://www.sciencedirect.com/science/article/pii/S0006291X09004306">less satiating</a> (so its consumption was associated with overeating), while another published in the <a href="http://jn.nutrition.org/content/139/6/1253S.abstract">same year</a> concluded that “the case for fructose being less satiating than glucose … is not compelling.” </p>
<p>The <a href="http://www.ncbi.nlm.nih.gov/pubmed/22351714">most recent</a> (2012) scientific review that addressed this issue concluded that “Fructose does not seem to cause weight gain when it is substituted for other carbohydrates in diets providing similar calories. Free fructose at high doses that provided excess calories modestly increased body weight, an effect that may be due to the extra calories rather than the fructose.” In short, if you overeat, you can expect to put on weight!</p>
<p>But there is <a href="http://www.ncbi.nlm.nih.gov/pubmed/20086073">evidence</a> that, when taken in liquid form (such as soft drinks or fruit juices), consumption of fructose is associated with higher energy intake, increased body weight, and the onset of metabolic syndrome.</p>
<p>So what are we to make of all this? At this relatively early stage in our attempts to elucidate the role fructose may play in the epidemics of obesity and type 2 diabetes, it’s probably safe to conclude that very high fructose intake can have serious and adverse metabolic effects in humans. But there’s no convincing evidence to support the claim that fructose is the sole cause of these epidemics, or that fructose intake at moderate doses is harmful.</p><img src="https://counter.theconversation.com/content/7424/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>In 2003 Chris Forbes-Ewan received funding from:
National Health and Medical Research Council (NHMRC) for his contribution to establishing the Nutrient Reference Values for Australia and New Zealand. His contribution was to assist in determination of the Estimated Energy Requirements. </span></em></p>Sucrose or sugar has two components – glucose and fructose. Glucose is present in virtually all naturally-occurring sweet foods and also exists as starch (although in a different chemical form, so it doesn’t…Chris Forbes-Ewan, Senior Nutritionist, Defence Science and Technology OrganisationLicensed as Creative Commons – attribution, no derivatives.