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Health Check: the untrue story of antioxidants vs free radicals

Antioxidants are a commonly promoted feature of health foods and supplements. They’re portrayed as the good forces that fight free radicals – nasty molecules causing damage thought to hasten ageing and…

Antioxidants are often portrayed as the good forces that fight evil free radicals. Markus Lütkemeyer

Antioxidants are a commonly promoted feature of health foods and supplements. They’re portrayed as the good forces that fight free radicals – nasty molecules causing damage thought to hasten ageing and cause chronic diseases.

The simple logic that antioxidants are “good” and free radicals are “bad”, has led to the idea that simply getting more antioxidants into our bodies, from foods or supplements, can outweigh the impacts of free radicals.

Sadly, biology is never this simple, and antioxidants are not a free radical free pass.

We are exposed to free radicals every day; they’re produced in our bodies as part of normal functioning. Such normal levels are easily tolerated.

But habits such as smoking, drinking, and eating processed foods all increase exposure. These additional free radicals may increase the risk of lifestyle and age-related diseases, such as cancer and cardiovascular disease.

Free radicals explained

Free radicals are very reactive molecules. In the body, a chemical reaction occurs between free radicals and the molecules that make up our cells.

This inactivates the free radical, but turns the other molecule into a new free radical. The process continues in a chain reaction, damaging each molecule as it goes on.

These reactions can alter the structure and function of molecules; when enough molecules are damaged, cells can stop functioning correctly, or die.

Eating processed food increases exposure to free radicals. eric molina

Damage to DNA by free radicals can result in mutations and promote cancer. Free radicals can also oxidise low-density lipoprotein or LDL (“bad” cholesterol), making it more likely to get trapped on the artery walls, clogging blood vessels and leading to cardiovascular disease.

Sometimes, free radicals are very helpful, for example, in an oxidative burst. This happens when special immune cells, known as phagocytes, deliberately release free radicals as part of a cocktail of chemicals to kill and digest bacteria and viruses.

Our antioxidant heroes

Antioxidants can stop the free radical chain reaction. They can react with free radicals without getting damaged or becoming a free radical themselves.

There are hundreds of substances that can act as antioxidants. Well-known antioxidants include vitamin C and vitamin E, both of which are found in fruits and vegetables.

Vitamin C is mainly found in citrus fruits and berries, while vitamin E is abundant in nuts and green leafy vegetables.

The ability of antioxidants to scavenge free radicals has led to the suggestion that consuming large amounts of antioxidants might lessen the free radical damage that leads to chronic diseases and ageing.

And there’s little doubt that a diet including sources of antioxidants is necessary for good health. Indeed, studies have shown that cancer rates are lower in people with diets rich in fruits and vegetables.

Not all roses

But the benefits of supplementing diets with additional antioxidants are yet to be shown. In fact, some studies have shown that taking antioxidant supplements can sometimes increase the risk of cancer.

This might be because antioxidants may be actually harmful under certain conditions. At high concentrations, substances that normally act as antioxidants can have the opposite effect and act as a pro-oxidant. This may be because antioxidants compounds, such as vitamin C, react with other molecules in the body, not just free radicals.

Berries are high in vitamin C. Susy Harris

Some of these reactions, such as the Fenton Reaction, actually produce additional free radicals. When antioxidant concentrations get too high, the free radical-producing effect can outweigh the free radical-fighting effect.

Also, not all antioxidants are the same; each has unique chemical behaviours and biological properties. This means that no single substance can replace the multiple functions of a variety of antioxidants.

A growth industry

Despite these uncertainties about their efficacy, supplemental antioxidants are a boom industry, sold as a health panacea and added to a range of processed foods, including juices, cereals, chocolate bars, and alcoholic beverages.

But the benefits of antioxidant-rich food is likely due to the entire nutritional package that comes from a diet rich in natural and whole foods. Adding antioxidants to processed foods means many healthy components of whole foods are missing.

So it’s unlikely that antioxidant supplements will be as successful in preventing disease as a healthy, varied and balanced diet. And while antioxidants may help protect the body from free-radical damage, as is often the case in nutrition, more is not always better.

The myriad other components of foods that are natural sources of antioxidants may also be responsible for their beneficial effects.

The best thing you can do for good health is to keep eating between five and eight servings of fruit or vegetables every day and to steer clear of unnecessary, and potentially harmful supplementation.

Join the conversation

65 Comments sorted by

  1. Chris Booker

    Research scientist

    Great to see an article covering this topic, I'm so sick of seeing the 'great source of antioxidants' ads on TV and thinking 'it's so much more complicated than that', but all most people would hear is the simplified impression that free radicals = bad. And this plays straight into the hands of the food manufacturers.

    I'm surprised you didn't also mention that free radicals are generated during exercise, and there is actually some evidence that they may mediate some of the beneficial effects of exercise.

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    1. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Chris Booker

      Hi Chris,

      You make a good point about exercise, but I left it out because its another one of those not so straight forward things, and I didn't have to words available to make it clear. So, I didn't want to risk misleading anyone, and I didn't want to make anyone think that because it produces free radicals that exercise might actual be bad for you.

      Basically, although vigorous and exhaustive exercise itself increases free radical production, because it increases oxygen metabolism, there…

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  2. Marco Dabizzi

    logged in via LinkedIn

    Great article, one of the few really informative and without prejudices about food on The Conversation. That to me bring back to another comment I left a few days ago about having a balanced diet, with another poster asking me what's a balanced diet.

    A balanced diet is a little bit like the definition of porn: I can't describe it to you, but I can recognize it is I see it.

    It seems that in the last 20 years many people started thinking about food like a medicine, avoiding some foods to not…

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    1. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Marco Dabizzi

      Great comment Marco! I think the important thing to remember is that living well might not necessarily mean you live longer, but it might mean you enjoy a better quality of life in the years that you have.

      Interestingly, I always thought I had a balanced diet, because I had a bias towards whole foods and fruits and veges and only ate processed foods as "sometimes" foods. As I have gotten further into my studies in nutrition I realised that this is not really good enough, I didn't have any variety in the fruits and vegetables I ate, just the same 6 or so over and over again. now I pay more attention to variety and buy what is season, rather than the old staples. I feel more nourished and it has actually ended up cheaper!

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    2. Trevor S

      Jack of all Trades

      In reply to Emma Beckett

      " As I have gotten further into my studies in nutrition I realised that this is not really good enough, I didn't have any variety in the fruits and vegetables I ate, just the same 6 or so over and over again."

      That's interesting, Many animals (sapiens aside) tend to eat the same diet repetitively. I thought there was some thinking that eating the same foods was a good thing (assuming they were good foods of course)

      That aside, go back 100 years or more and look to cook books. So completely different, more permaculture like in that they ate what was around. Crow, Swan etc etc We are of course restricted by Government legislation in this area today from exploring many of these additions to diet. That said I have several non-indigenous friends partaking of Goanna, Snake and Macropod regularly, as they are plentiful where we are (cheap and keeps the carbon budget low) and several indigenous friends eating "Porcupine", as they call it.

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    3. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Trevor S

      Interesting thought Trevor, certainly made me think for a minute, but I don't think its one size fits all. Different species have different essential nutritional requirements. I'm not an expert in any of the species you mentioned and even this is getting a bit far from my expertise, but I know for example that even though they look pretty similar cats can't survive on dog food because cats can't use beta-carotene as a source of vitamin A and dogs can.

      I was eating enough fruit and vege, but…

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  3. Geoff Russell

    Computer Programmer, Author

    Without wishing to promote the superfood scammers, I think there's rather more evidence for food as medicine than you are suggesting, for example the DNA damage after exercise is avoidable:

    http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8824378

    And more importantly, the entire way a body functions changes with diet ... in particular you can down-regulate oncogenes and up regulate tumor suppressors.

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430265/

    But the true value of dietary change comes when you stop focussing purely on personal health but consider wider environmental and biodiversity issues.
    Then it becomes blindingly obvious that some foods are taking a considerable toll on the planet ... beef in particular, and others take a considerable toll on the animals via cruel and vicious production methods ... factory farmed chickens and pigs in particular.

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    1. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Geoff Russell

      Hi Geoff,
      I'm not at all against "food as medicine"- good diet is one of the best preventions against disease. But i only really support this when FOOD as opposed to supplements is used. The real point I was making is that supplementation is not equal to dietary intervention. What I am concerned about is the isolation or synthetic generation of components of foods being taken in mega doses or "balance out" other lifestyle choices or to use to market food as healthier, because the evidence is showing that this supplementation does not have the same health benefits as eating foods rich in the same compounds.

      Like Marco said above, it always comes back to balance.

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    2. Sue Ieraci

      Public hospital clinician

      In reply to Geoff Russell

      Hi, Geoff,

      I don't think that first paper actually shows what you say - it's a pilot study with only ten people that only measured blood test values. I don't have access to the full paper at the moment. The issue with exercise is that the oxidative stress is short-term - occurring during the time when muscle metabolic demands exceed the normal blood supply. That;s when anaerobic metabolism kicks in. We have physiological pathways for dealing with short-term anaerobic metabolism.

      The prostate…

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    3. Geoff Russell

      Computer Programmer, Author

      In reply to Sue Ieraci

      Sure Sue. Both studies are small, and in need of replication, but plenty of science is based on small studies done well.

      Emma. I don't believe in unjustified generalisations (ever:)). The evidence against red and processed meat (both foods) is overwhelming and the US IOM recommends that all adults over 50 supplement with B12, because, in lay language, it works better than the stuff in meat. So we have supplements which work and others which are highly hyped but totally unproven while another group of people sells a product that is known to be harmful and has been calculated to cause about half of our bowel cancer annually. Which group is worse?

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    4. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Geoff Russell

      Hi Geoff,

      Why does it have to be one is worse than the other? Does the approach need to be that reductionist? Meat can easily be included in a healthy and balanced diet, over consumption is more the problem.

      Some supplements are beneficial and are recommended in certain age groups and in certain medical conditions. Folate in pregnancy and vitamin D in osteoporosis for example. But, not all vitamins and supplements are created equal and the evidence certainly leans towards antioxidant supplementation not being beneficial, other supplements are each their own point for consideration. The conclusion in this article was only directed at antioxidant supplements.

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    5. Geoff Russell

      Computer Programmer, Author

      In reply to Emma Beckett

      Ok we agree on the supplements.

      From a strictly self-centered view, then sure, it's certainly possible to eat small amounts of whale, dog, cat, panda or anything else. What's the threshold for red & processed meat? In the WCRF report the dose response curve kicks up at about 1 serve per week. So almost all Australians over consume. But curiously most people don't eat whales and pandas because most people aren't only concerned about their own health. So if anybody has concerns about climate change…

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    6. Geoffrey Harold Sherrington

      Boss

      In reply to Geoff Russell

      Geoff Russell'
      Unfortunately there is no accepted basis for your vague assertion that methane does those things you mention. Sure, there are spectrometry measurements of the IR absorption of methane and CO2, but the same link to heating cannot be shown for CO2 either. If you failed to notice, global temperatures have been flat for over 15 years, while CO2 in the air has risen appreciably. Is there no link? It's looking like there is not.
      We have been asking for a quantitative link between GHG and…

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    7. Geoffrey Harold Sherrington

      Boss

      In reply to Geoff Russell

      Geoff Russell,
      No, it's not available at those sites, which is why I raise it as a concern.
      Show me where you think you found it?

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    8. Geoff Russell

      Computer Programmer, Author

      In reply to Geoffrey Harold Sherrington

      You asked for a link between "air temp and CO2". That link is mediated by the oceans, the more basic link is between global heat content and CO2. There is more heat arriving than leaving ... satellites can measure this ... as they have done since the first one launched in 1984 (from memory). Most of the heat is going into the oceans but we will eventually have to "pay the piper". It beggars belief that you claim to have been paying attention since 2005 but haven't read this stuff ... for others who may be reading, here's a recent post from real climate

      http://www.realclimate.org/index.php/archives/2013/09/what-ocean-heating-reveals-about-global-warming/

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  4. Paul Prociv

    ex medical academic; botanical engineer at University of Queensland

    A very useful comment on a grey area in nutrition that has been increasingly exploited by an army of mercenary charlatans. When you consider just what nutrient molecules have to confront on their way through your system, facing gut enzymes and pH changes, absorption and modification by liver cells etc., it would not be surprising if most of their test-tube antioxidant activity had not dissipated by the time they reached the end cells where this might have had any usefulness.
    From my recollection of undergraduate biochemistry almost 50 years ago, I thought that the pentose phosphate shunt, very active in liver, red blood cells and other tissues, was the major source of endogenous antioxidants (mainly NADPH), far outstripping anything you could eat. How does that fit with modern knowledge? [check it at: http://en.wikipedia.org/wiki/Pentose_phosphate_pathway]

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    1. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Paul Prociv

      Hi Paul,

      The pentose pathway is one of the main cellular antioxidant defence mechanisms, if you want a recent academic article on it, see http://www.ncbi.nlm.nih.gov/pubmed/?term=The+pentose+phosphate+pathway%3A+an+antioxidant+defense+and+a+crossroad+in+tumor+cell+fate

      To sum up the endogenous antioxidant molecules in a list for those who are interested the major ones are: Glutathione, Alpha-lipoic acid, Coenzyme Q, Ferritin, Uric acid, Bilirubin, Metallothioneine, L-carnitine and Melatonin.

      I always think its funny when I see ads for skin creams containing Coenzyme Q... I'm not a cosmetics expert, but I'm not sure smearing it on the external dead layer of my skin is really going to help much with the free radicals....

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  5. Sue Ieraci

    Public hospital clinician

    Thank you for the article.

    ''Sadly, biology is never this simple'' sums it up well. Along with ''as is often the case in nutrition, more is not always better.''

    Nutrition seems to be a fertile ground for both pseudo-science and marketing. It makes little sense to be suspicious of ''Big Pharma'' while swallowing ''Big Vita'' and "Big Supplementa'' whole (so to speak).

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    1. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Sue Ieraci

      So true Sue! That is exactly why I try to write these articles, I am very passionate about communicating good and real science so that people can be informed to judge for themselves what is put out there in the marketing world.

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    2. Geoffrey Harold Sherrington

      Boss

      In reply to Emma Beckett

      Emma,
      Chemists would see a problem in that oxidation and reduction can take place over a large and flip-flop scale. Analogy, the pH scale - where a substance can be alkaline or acidic, depending on whether it is reacting with something further up or lower down in the continuum.
      L Ascorbic acid, vitamin C, is used in the lab as an oxidant sometimes and a reductant at other times. It depends what it is reacting with. (We tend not to use 'anti-oxidant' when 'reductant' suffices.)
      Also, I believe that a few free radicals are generated in the body by the passage of ionising radiation such as Cosmic rays. These have plausibly been present throughout human evolution, so perhaps the body has created mechanisms to deal with them.

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    3. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Geoffrey Harold Sherrington

      Hi Geoffrey,

      Yes, I did mention in the article that Vitamin C is sometimes and oxidant and sometimes a pro-oxidant. I didn't want to confuse non-scientist by chopping nad changing between antioxidant and reductant, as antioxidant is the term used in nutrition and food marketing, it is the term most people are familiar with.

      The human body does have endogenous sources of antioxidants, yes. If you look in my comment above in response to Pauls comment I have listed the main ones.It is hypothesised and there is preliminary evidence to suggest however, that supplementing with antioxidants actually reduces your endogenous production as your body attempts to maintain homeostasis, rendering the supplementation basically useless.

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  6. Tom Hennessy

    Retired

    As Linus Pauling pointed out, too many free radicals, too much oxidation. Noone is arguing the basics of Science, oxidation is used to defeat pathogens, just the fact there are too many free radicals in the body. Now that Linus is dead we have those who couldn't even carry his books, calling him crazy. The Herbivore Hypothesis / age-related iron accumulation, gives an explanation to where the increased oxidation comes from, that oxidation we seem not to be able to control without the supplementation of our diet with antioxidants as per Linus Pauling. Age-related iron accumulation.
    "Iron overload has a high prevalence in postmenopausal women with fragility fracture"
    http://scibite.com/site/library/2013_10/1/0/24091266.html

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    1. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Tom Hennessy

      My apologies, but I'm not sure I entirely follow your point Tom? I did mention the role of oxidation in the immune system in the article. I'm not arguing with the chemistry or the physics, I was commenting on the fact that the over simplified logic of take more antioxidants undo the free radical damage is not quite the full story.

      True, iron overload can contribute to free radical accumulation, particularly it can damage tissues by catalyzing the conversion of hydrogen peroxide to free-radical ions that attack cellular membranes, protein and DNA. Excess iron can also exacerbate the prooxidant effect of excessive vitamin C. That is why the point I made was that a balanced diet is necessary, balance means avoid excesses as well as deficiencies.

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    2. Tom Hennessy

      Retired

      In reply to Emma Beckett

      "That is why the point I made was that a balanced diet is necessary, balance means avoid excesses as well as deficiencies."

      Which is why I placed the fragility fracture study in which it shows iron overload in the elderly whom one can assume carried on their lives in 'moderation' but still managed to acquire iron overload.

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    3. Tom Hennessy

      Retired

      In reply to Emma Beckett

      "It is probable that a chronically high intake of heme iron can lead to high body iron stores"

      The iron in meat is different, in that it is chemically bound to heme, thus making it what is known as heme iron and this heme iron is absorbed differently from the iron found in supplements and vegetables / plants.

      Studies have shown the iron from plants and supplements is downregulated when a set limit is met.
      "Unlike nonheme iron, heme iron absorption is not substantially reduced as iron stores increase"
      The iron from meat though is absorbed "at all times of iron status", not being very well controlled by the body.
      "Title: ABSORPTION OF NONHEME, BUT NOT HEME IRON, IS SUBSTANTIALLY REDUCED WITH HIGH IRON STORES"

      Thusly, slowly but surely rising to higher and higher levels in the body, age-related iron accumulation, the fragility frailty fracture factor.

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    4. Tom Hennessy

      Retired

      In reply to Emma Beckett

      Another problem is, heme iron increases the absorption of other iron ingested at the same time, so iron fortified flour is now absorbed when it normally wouldn't be absorbed.

      "When non-heme iron (plant-based) is eaten with a source of heme iron (animals), this improves the absorption rate of the non-heme iron. According to the NIH, this will increase non-heme iron absorption up to three times"

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    5. Tom Hennessy

      Retired

      In reply to Emma Beckett

      "but I'm not sure I entirely follow your point Tom?"

      The point being, intelligent people, debating back and forth as to the benefits of supplemental antioxidants but failing to address the elephant in the room, why is anyone talking about antioxidants. It is because of oxidation, people know its bad, in excess, Linus Pauling said, everyone was in excess oxidation. Hence, the most simple of advice, take the well known source of antioxidant, vitamin C. Now, there is argument, one way and the other whether vitamin C does or doesn't increase oxidation, but it is really neither here nor there. The fact is , everyone seems to agree, oxidation is somehow involved in ageing, disease and just generally fatigue. The thing is, was Linus right, did Linus see and excess oxidation in humans, he used to calculate the orbits of molecules in his haid, you know that. Yes, he saw oxidation / rust , age-related iron accumulation, never recognised it though.

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    6. Tom Hennessy

      Retired

      In reply to Emma Beckett

      "True, iron overload can contribute to free radical accumulation"

      What iron overload is, though, that is the question. Is the point, excess oxidation, a lot lower than everyone is accepting?As evidenced here, by just simply comparing vegetarians to meat eaters?

      "A 2001 study involving 30 lacto-ovo vegetarians and 30 meat-eaters reported a correlation between insulin resistance and body iron stores, as measured by serum ferritin concentrations. The vegetarians had eaten eggs but no meat within…

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    7. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Tom Hennessy

      So you are just bothered that I didn't credit Linus Paling? Sure he was an amazing chemist, hence the Nobel prize, but his work on vitamin C and his advocacy for vitamin C was very controversial.His study that showed vitamin C improved cancer was shown to be scientifically flawed (the vitamin C treatment group was stacked with the patients who were healthier at the time of entering the trial, thus skewing survival rates). In the decades since that study many more have shown antioxidant supplements…

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    8. Marco Dabizzi

      logged in via LinkedIn

      In reply to Tom Hennessy

      Once upon a time people learned how to counterbalance some deficiency in their diet. Some traditional recipes like "pasta and fagioli" (pasta with beans), "risi e bisi" (rice with peas), "polenta con baccalà" (polenta with salted cod) combined two different ingredients to compensate for missing amino acids of one of them.

      The farmers use to say that every meal should end with a piece of cheese, and milk was... well, milk, not the diluted whitey water sold nowadays under the well marketed labels of "skim" milk.

      All this to say that calcium is a natural anthagonist of iron, and with a balanced diet (again!) that includes a wide number of dairy product and a healthy exposition to the sun light for vitamin D there wouldn't be any problem of iron accumulation.

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    9. Geoffrey Harold Sherrington

      Boss

      In reply to Emma Beckett

      Emma,
      You have started to point out a fundamental problem, thank you.
      That problem is that some vendors are using a promotional approach, with much advertising to encourage people to take more than would otherwise be needed.
      The more acceptable way would be to provide treatments for those diagnosed with a deficiency or some other need to take a product.
      The advertising-promotional method is probably bad overall because (a) manufacturers are spending funds and manufacturing capacity on something…

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    10. Geoff Russell

      Computer Programmer, Author

      In reply to Marco Dabizzi

      Sorry Marco ... something that's false is false, regardless of how often it's repeated. There are no amino acid shortages in pasta that require beans and vice versa. It's easy to confirm. Just look up any nutritional database and verify against the WHO amino acid requirements. Ditto brown rice and peas. Both white rice or polenta can give serious vitamin deficiencies on their own. The protein combining meme is ubiquitous but run the numbers, check it, it's rubbish. Check the AIHW database and try and find anybody in Australia in recent times with an amino acid imbalance. I spent half a day looking one day and didn't find anybody. It's a theoretical possibility but it doesn't happen. If you want an authority, check Marion Nestle's "What to eat", she says the same thing. I'm not knocking food variety, just saying that it isn't an amino acid issue.

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    11. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Geoff Russell

      Sorry Geoff, Pasta is not a complete source of protein, therefore it does not contain all 10 essential amino acids. I'm with Marco, adding beans to pasta is a good way to ensure you get all your essential amino acids. This is called using complementary proteins, combining two or more sources of food to build a complete protein meal. To be clear though, you don't need to get all the amino acids in a single meal, but you do need to have the 10 essential amino acids regularly, as they can't be stored…

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    12. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Emma Beckett

      However Geoff, I do agree that amino acids aren't the only issue. If you are deficient in vitamins and mineral, that will certainly impact your ability to process and utilise amino acids correctly. Again, it comes back to the whole idea of diet and the body as one big complex unit, there is no point of being balance or in excess in one area if you are in deficiency or overload in another area. This is why nutritionists will always recommend variety and balance for a healthy diet.

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    13. Geoff Russell

      Computer Programmer, Author

      In reply to Emma Beckett

      As I said, misinformation is rampant ... even the CDC

      Please go and check the amino acid tables on NUTTAB 2010

      http://www.foodstandards.gov.au/science/monitoringnutrients/nutrientables/pages/default.aspx

      Or, check the NHMRC Nutrient Reference Values document for any special needs that vegetarians might have to get adequate protein. There aren't any. Veg*n aren't all geniuses who manage the extraordinary task of balancing amino acid intake. It's simply not an issue. Doctors sorted all this out in the seventies when they thought the world had a "protein gap" ... and discovered it was just a food shortage ... google "The great protein fiasco" and have a look at the history...

      http://jn.nutrition.org/content/116/7/1364.full.pdf+html

      When I have more time, I'll email you some data.

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    14. Tom Hennessy

      Retired

      In reply to Emma Beckett

      "you are just bothered that I didn't credit Linus Paling?"

      I am not bothered, I am just pointing out that Linus spotted excess oxidation, which is why he advocated antioxidant vitamin C. When I say neither here nor there, it is in reference to Linus' work in that he advocated vitamin C because he recognised increased oxidation in man. He isn't the only one who has noticed this excess oxidation.

      "There is no point getting caught up just on iron overload"

      That is my whole point. Linus, a genius, spots oxidation but never figures out where it is all coming from. I pointed out how iron builds progressively, accumulates in the body and everyone knows, iron rusts / oxidises, explaining the excess oxidation which Linus spotted.

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    15. Tom Hennessy

      Retired

      In reply to Marco Dabizzi

      So, what you are saying is when the researchers just randomly tested vegetarians against meat eaters, the fact all the meat eaters had higher iron stores is mere coincidence?
      "Iron Intake, Meat, and Type 2 Diabetes
      Consumption of heme iron found in animal products, particularly red meat, is associated with increased insulin resistance and diabetes risk in men and women. Unlike iron found in dried fruit, kelp, some whole grains, and brewer's yeast, heme iron from red meat, fish, and poultry is highly bioavailable and readily stored in the body"
      http://www.townsendletter.com/May2007/shorts0507.htm

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    16. Marco Dabizzi

      logged in via LinkedIn

      In reply to Geoff Russell

      Well, Geoff, if you think I'm a vegan it means that my English is worse than I thought...

      Now, in the North East of Italy there was a huge diffusion of pellagra (sorry, I don't know the English term), a malady due to the diet consisting mostly in mais (polenta). The tryptophan and niacin in mais are not available without soaking it in water and lime like the Mexicans used to do (but not the Italians).
      European Food Information Council: http://www.eufic.org/article/it/artid/origini-mais-pellagra

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    17. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Geoff Russell

      Sorry Geoff, I should have been more clear, I can see now why you are confused. To be defined as a complete protein, it needs to contain all the essential amino acids in ADEQUATE proportions. Simply having them all there isn't enough if they aren't in the right combination or absolute values. That's not to say you can't get them all from non-animal sources (I do on a daily basis!). If you ate nothing but pasta, I'm sure you could get enough of them all eventually, but you would have to eat a whole…

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    18. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Tom Hennessy

      Yes Tom, no one is arguing that oxidation in the body exists and that it causes damage. In fact I have said in the article that free radicals are produced in the body on a daily basis and that we add to them with other activities. Perhaps you have missed where we said that in the original article because I said free-radicals instead of "oxidants" in general.

      What we are trying to explain that the simple logic of "take an antioxidant to balance out the bad oxidants" is not as simple as it seems. Take too much vitamin C and you end up increasing the oxidation, not cancelling it out.

      Perhaps the tone and context is lost in the typing (the downside of this kind of forum), because it feels to me like you are trying to disagree with me, but you are really mostly repeating what I have already said in the article. Apologies if I am misunderstanding.

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    19. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Tom Hennessy

      Hi Again Tom,
      I think we are talking across purposes, resulting in the confusion. Clearly, as the author, this is my fault for not making it clear in the first instance. My apologies.

      Free radicals and oxidants are linked but not the same thing. Free radicals are involved in contributing to oxidative stress, but not all oxidative stress is caused by free radicals, free radicals are just a component of it. Furthermore, Free radicals can be either oxidants or reductants.

      Oxidation/oxidisation…

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    20. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Emma Beckett

      *sorry, that should have read, no one is arguing that oxidation in the body doesn't exits and that it doesn't damage. Clear that does exist and that is what causes "oxidative stress". Please see the other comment I just left that clarifies the relationship between free radicals and oxidative stress. It came up a little higher in the conversation tree than this one.

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    21. Geoff Russell

      Computer Programmer, Author

      In reply to Emma Beckett

      I'm not confused. Run your program and work it out. Get your program to tell you how many of each amino acid you'd get from a couple of thousand Calories of brown rice or pasta or beans ... then compare it with the WHO amino acid requirements.

      Here's a research study which tried it out in the real world ...

      http://ajcn.nutrition.org/content/24/2/181.abstract

      Of course in the real real world nobody eats like this because it's boring as ....

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    22. Marco Dabizzi

      logged in via LinkedIn

      In reply to Geoff Russell

      Geoff, I can't read the article but the abstract is not related to what we were talking about.

      "Since replacement of 20% of the nitrogen from wheat equinitrogenously by rice or peanut butter did not significantly improve the utilization of wheat protein, substitution of peanuts or cereal grains for a portion of the wheat would not prove to be nutritionally efficient in adult man when potatoes and other vegetables and fruit are simultaneously consumed. "

      Peanuts or cereal can't do anything to compensate the unbalanced amino acids profile of wheat, beans do. Moreover, the article, written in 1971, talk about a diet adequate for maintenance of adult man, that's not the same thing as an ideal diet.

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    23. Sue Ieraci

      Public hospital clinician

      In reply to Marco Dabizzi

      Hi, Marco - I'm familiar with that bit it Italian history you are talking about. Pellagra is called the same in Australia - it's Vit B3 (niacin) dietary deficiency.

      As you say, maize was a new world crop that was ground with lime and eaten with beans. When maize (corn) was taken from the New World to Europe, it was ground and made into a porridge (polenta) without being ground with lime. The lime breaks up the kernel shell, so that the grinding releases the Niacin from the kernel. Without this preparation, little or niacin is released. When the rural poor existed on polenta with very little other food, they became niacin deficient. So, pellagra is about malnutrition, but not specifically protein malnutrition (which they probably also had as well).

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    24. Tom Hennessy

      Retired

      In reply to Emma Beckett

      "but not all oxidative stress is caused by free radicals"

      But all free radicals are caused by oxidation, isn't that how free radicals begin, oxidation?

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    25. Marco Dabizzi

      logged in via LinkedIn

      In reply to Sue Ieraci

      You are right, it was just an example of integration of two different food sources to create a more balanced meal: polenta was in fact often combined with baccalà (salt dried cod), a great food of niacin, to balance the scarce niacin in the maize.

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    26. Sue Ieraci

      Public hospital clinician

      In reply to Marco Dabizzi

      Right, Marco. There is an interesting food history relating to the role of various staples in Italy, which I'm sure you know.

      The south, of course, had wheat and some rice as staples. Colder mountainous areas also had a tradition of a staple ''porridge'' - sometimes using chestnut flour. The south sometimes ground chickpeas into flour. It is said that, when maize arrived from the new world, it was natural for it to be ground and made into course flour, to be cooked as ''porridge'' (like polenta).

      It was really only the very poor who existed just on the staple and had very little protein or other niacin sources. Of course the seasiders had fish, but, like you say, salted dried cod was able to be preserved for long periods, so provided an alternative protein source.

      I must admit I am no fan of baccala' - I still have unpleasant memories of it cooking away on Good Friday, when I was a child (after it had soaked for days). Maybe time to have another go at it!

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    27. Geoffrey Harold Sherrington

      Boss

      In reply to Tom Hennessy

      Tom,
      It depends how strictly you define redox purely in terms of loss or gain of electrons.
      If you go more broadly, ionising radiation can generate free radicals. I think that is not a conventional view of oxidation.

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    28. Tom Hennessy

      Retired

      In reply to Geoffrey Harold Sherrington

      "ionising radiation can generate free radicals. I think that is not a conventional view of oxidation"

      Ionising radiation is though part of the oxidation mentioned in the article, naturally occuring oxidation which the body normally would be able to quench, since we are a mammal and technically evolved long enough to be able to withstand simple sunlight, but, in a situation where the ability to quench those free radicals, oxidation, reactive oxygen species, etc, is offkilter, to use a medical term…

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    29. Geoffrey Harold Sherrington

      Boss

      In reply to Tom Hennessy

      Tom,
      It is too many years since I studied free radicals, but any mechanism that produces a charged particle from a neutral entity should also produce an entity with opposing charge, to preserve neutrality. If cosmic rays smash a molecule apart, electrical neutrality and hence the designation of oxidation or reduction should be balanced. That is, you have to pay attention to other reaction products, apart from a free radical.
      I suspect that there is some confusion about what a free radical is, what a typical reaction series is and what causes mutations arising from damage to genetic chemistry. Is there some (trendy but not necessarily scientific) demonization of free radicals going on here? Are anti-oxidants (terrible term) being held up as good guys? If they are, sorry, chemistry does not assign personalities to species.

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    30. Tom Hennessy

      Retired

      In reply to Geoffrey Harold Sherrington

      "Are anti-oxidants (terrible term) being held up as good guys? If they are, sorry, chemistry does not assign personalities to species."

      Therein lies the rub, Linus was specific in his conclusion, vitamin C specifically because it was an obvious, logical, fit, based on his chemistry background and genius. Animals, compared to man, do not suffer the various diseases in anyway comparable to humans. Humans manifest "100 different types of arthritis" for gods sake. Something, has gone wrong in humans and diet, improper diet, herbviore eating meat, explains it, and if taken with research already conducted, is proven on paper but simply disregarded as cavalierly as bloodletting was over a hundred years ago, replaced by heroin.

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    31. Marco Dabizzi

      logged in via LinkedIn

      In reply to Tom Hennessy

      You are right Tom, many animals suffer far less maladies than humans. They often don't live as much, though, eaten by a carnivore once they can't run so fast anymore or just left behind to die... I'm sure that if we lived in a crocodile infested area with no shelter and we needed to provide for our own food we'd have far less issues of arthritis and other old age related problems ourselves.

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    32. Tom Hennessy

      Retired

      In reply to Marco Dabizzi

      "animals do not get atherosclerosis – a fact well known to vets for the past 50 years"

      There are just some facts that are irrefutable.

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    33. Marco Dabizzi

      logged in via LinkedIn

      In reply to Tom Hennessy

      "animals do not get atherosclerosis"

      Of course they don't, they have a better diet than human beings, they are more sensible to themes like sustainability, they don't destroy the environment and they don't eat red meat.

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  7. Geoffrey Harold Sherrington

    Boss

    Ema & Mark,
    Much of this is old hat. I wrote about it in 2005, see pp 40-41 of
    http://www.skeptics.com.au/wordpress/wp-content/uploads/theskeptic/2005/3.pdf
    .......................
    It is not just anti-oxidants that concern me about abuse of chemistry.
    . Seaweed growth enhancers are widely advertised for the home gardener. I am unaware of any ingredient that has been identified as having an effect, but I'd be pleased to hear. Last time I looked, Maxicrop had been trounced in a long New Zealand…

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    1. Emma Beckett

      Doctoral scholar, Human Molecular Nutrition Laboratory & Casual Academic at University of Newcastle

      In reply to Geoffrey Harold Sherrington

      Hi again Geoffrey,

      "Much of this is old hat"- Thanks for your comment, but we weren't trying to be novel, the aim of the article was to communicate the science to the masses through this platform, sometimes that means writing about things others have written about before, in fact it is necessary, as all the data used to write this article was sourced from other primary research articles.

      Maybe I can tackle some of the nutritional ones in your list in future articles!

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    2. Tom Hennessy

      Retired

      In reply to Geoffrey Harold Sherrington

      " I am unaware of any ingredient that has been identified as having an effect, but I'd be pleased to hear."

      I'd have to look a bit to find the reference but I have read seaweed makes a good fertilizer partially because it contains natural herbicides. So, if that is correct one can assume the growth of the plants would be enhanced by seaweed due to the fact herbicides have been well studied and shown to enhance plant growth.

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    3. Geoffrey Harold Sherrington

      Boss

      In reply to Tom Hennessy

      Tom,
      Thank you for your comment.
      It is experimental data that I'm seeking. Hearsay is often unreliable.

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    4. Sue Ieraci

      Public hospital clinician

      In reply to Emma Beckett

      Thanks for all your patient clarifications, Emma. Your article is very relevant.

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