Might too many antioxidants cause cancer?

Could you please comment on the recent statement by James Watson (DNA discoverer) that antioxidants can actually cause cancer.

pprender / Originally Posted in Maxing Out on Antioxidants


The full-text of Jim Watson’s article can be found here. As you can see, he’s talking about “antioxidative nutritional supplements,” something I’ve also warned about in videos such as:

Whenever possible we should get our nutrients from produce, not pills.

image credit: Ragesoss / Wikimedia Commons


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

42 responses to “Might too many antioxidants cause cancer?

Comment Etiquette

On NutritionFacts.org, you'll find a vibrant community of nutrition enthusiasts, health professionals, and many knowledgeable users seeking to discover the healthiest diet to eat for themselves and their families. As always, our goal is to foster conversations that are insightful, engaging, and most of all, helpful – from the nutrition beginners to the experts in our community.

To do this we need your help, so here are some basic guidelines to get you started.

The Short List

To help maintain and foster a welcoming atmosphere in our comments, please refrain from rude comments, name-calling, and responding to posts that break the rules (see our full Community Guidelines for more details). We will remove any posts in violation of our rules when we see it, which will, unfortunately, include any nicer comments that may have been made in response.

Be respectful and help out our staff and volunteer health supporters by actively not replying to comments that are breaking the rules. Instead, please flag or report them by submitting a ticket to our help desk. NutritionFacts.org is made up of an incredible staff and many dedicated volunteers that work hard to ensure that the comments section runs smoothly and we spend a great deal of time reading comments from our community members.

Have a correction or suggestion for video or blog? Please contact us to let us know. Submitting a correction this way will result in a quicker fix than commenting on a thread with a suggestion or correction.

View the Full Community Guidelines

  1. Supplements have never sat right with me. Mother Nature didn’t make supplement pill trees. She made whole foods. Eat an organic whole diet.

  2. In my Morning smoothies I have 2 large kale leaves and then 1 Tb each of ashwaganda, golden berries, goji berry, acai powder, maca, 2 TBS chia, hemp hearts, flax, raw cacoa nibs, 6 dates, 4 dried figs, 1/2 cup each of raspberries, blueberries and strawberries, apple, banana, pineapple, 1/3 cup wheatgrass juice, carrot and a few other fruits…in a vitamix with spring water…this makes 2 days worth of smoothies for my husband and myself. Am I over supplementing us or am I doing a body good?

    1. All of the “supplements” you are adding to your smoothie are of plant origin, not synthesized in a lab and therefore will have the benefit of the symbiosis of nutrients. The smoothie sounds delicious! If i were to make a suggestion, I would add more greens and less fruit, as a lot of fruit can increase blood sugar levels. :)

  3. Guess I’ll hold off on that colloidal silver purchase. However, in all seriousness here’s a question: Would you say that anti oxidants are always anti inflammatory? Or, put another way – if an anti oxidant has a high ORAC score (or whatever it is) is it also a better anti-inflammatory? Or, is there some other common denominator in food that makes it anti-inflammatory (such ginger or tumeric) and others not so much?

  4. My heads spinning because I don’t know which supplements to keep and which to discard. Should I continue with vegetable capsules of 500 mg of L -cysteine? Of 250 mg of L -carnitine? Omega 3-6 -9 vegan plant based swirl with flaxseed oil and borage oil? Also my health food store sold me on buying “cardio for life ” supplement. Is it safe?

    1. As a general rule the only supplement to recommend to folks on a whole food plant based diet is Vit B12 (see Dr. Greger’s 5 video series in Feb 2012 beginning with http://nutritionfacts.org/video/vitamin-b12-recommendation-change/ . Beyond that isolated nutrients have a bad track record Vit E, Vit A and Beta carotene supplements increase morbidity and mortality. Follow the links that Dr. Greger recommends above. I haven’t seen any good controlled scientific studies to support other supplements. The best science supports a varied whole plant based diet insuring adequate B12 intake. However each individual is unique and if you are having symptoms you should work with a physician who is knowledgeable in this area.

  5. what is your opinion regarding msm supplements. I take a heaped teaspoon of pure powder daily along with my raw vegan diet but have read a lot of conflicting opinions re the sulphur and it slowing the lymphatic system, according to Dr Robert Morse n.d and then the other side David Wolfe says it is a powerful detoxifier etc. Confused!!!
    your valued opinion please!!!

  6. Supplements could be a waste of money since most of them do not cover the antioxidant network and are not absorbed properly. I am an antioxidant scanner operator and most people we scan that take supplements of the store shelf, actually have a low score!! When you take supplements that covers the antioxidant network, and are taken twice a day (water soluble vitamins needs to be replenished since they only last 8-12 hours), and are absorbed properly, only then will your antioxidant score go up and strengthen your immune system. There is a wave of Optometrists around the country now adapting this scanner in their practices since it is the only tool to measure ones immune system and antioxidants in 90 seconds. Just my two cents:-)

  7. Dr. Greger, I think you may have misinterpreted Jim Watson. Unlike me, he doesn’t share your view on “produce, not pills”. See for example section 22 on page 8 of his article, where he states:

    “Blueberries best be eaten because they taste good, not because their consumption will lead to less cancer.”

    I think the crux of Watson’s position on antioxidants is summed up in the following quotation from that article:

    “In light of the recent data strongly hinting that much of late-stage cancer’s untreatability may arise from its possession of too many antioxidants, the time has come to seriously ask whether antioxidant use much more likely causes than prevents cancer.”

  8. Dear Dr Greger,
    My wife eats one to one-and-a-half lb of raw radishes each day (sometimes more) and can’t manage for long without a supply at hand – she developed this insatiable appetite for radishes about a year ago for no apparent reason. Are there likely to be any negative health effects associated with this dietary habit? Needless to say a significant portion of my day is now devoted to cutting and washing radishes…

    1. Peter: I am not a doctor nor am I an expert on nutrition. So, take this for what it is worth.

      My thoughts are: based on your description, it sounds like this would be a good problem to bring to a (plant-based) doctor. If your wife is eating 1.5 pounds of radishes, then she is not eating an array of other healthful foods. Any food in excess can be a problem. I don’t know if 1.5 pounds counts as “excess” or not. But when you say, “insatiable appetite” and “can’t manage for long…”, it sounds like it *could* be a medical (or psychological?) problem. Just something to think about.

      I hope it all works out for you both. And “Yeah!” for you helping with all those radishes!

  9. What about probiotics? I just found a Greek Yogurt replacement, So Delicious brand Almond cultured milk (and Coconut cultured milk) which contains active cultures…is eating yogurt or supplementing probiotics a good idea? I started eating vegan last week due to the education I received watching your video clips!! Today is day #6! Thank you!

  10. Could you please give your view as to whether the science currently supports the view that antioxidants are actually relevant to maintaining health, Put another way, when we say this food contains antioxidants, are we doing anything of significance.

  11. Hi, can you please comment on ecklonia cava? This is a type of seaweed. 1) would you consider its market sources to be whole foods (like amla powder) or ‘supplements’ to avoid? Some capsules seem to be whole powdered, and some are “water extracted” 25:1, frond and stipe. 2) It is marketed as having a high ORAC score – do you recommend it as a antioxidant? if so, the extration would seem to be a more concentrated antioxidant, but is it still “whole”? Thanks!

  12. Can you please advise how as I vegan I can be worry free about getting my protein intake and any other concerns for nutrition?

    1. Hi Beverly, here are the recommendations and a site listing gms of protein in foods:
      1. http://nutritionfacts.org/video/changing-protein-recommendations/ You can also use the Search functionality or Alphabetized List on the left side/navigation bar to find more.

      2. http://www.heartspring.net/list_of_vegetarian_protein_foods.html

      Its not hard to get protein so no need to worry if you are eating a healthy whole-food plants (not junk food vegan like chips, soda, licorice, etc.).

      Hope this helps get you at peace about protein, Jacquie

      1. Does anyone have any information about the JuicePlus supplements? They are whole fruit and veg, dried with limited processing and put in a capsule. On the surface it looks good but I want to find out more before I commit to taking them given the article above. Thanks

    2. Beverly: Here are my two favorite sites for explaining protein needs. If JacquieRN’s info didn’t suit, then if you work through these two articles, I’m sure you will be worry free ever more!


      http://www.drmcdougall.com/health/education/newsletter/archives/ (check out December 2003 for McDougall’s site, “A Brief History of Protein: Passion, Social Bigotry, Rats, and Enlightenment”. Also April 2007, “When Friends Ask: Where do you get your protein?”)

  13. Answer me this: my only proveable issue is that im allergic to but must recieve iron supplement iv treatment therapy. Im alergic to it. I havent had any recently, however, ive had a rediculous craving for Kerns Peach Nectar (peach puree) & on advice of my P.C.P. , am feeding my habit & have been since april. Now im as orange as an Oompa Loompa because of too mich vitamin A?! Is nothing good for you?! I have a one ounce stomach &can only drink about 22 oz.s of juice a day, slightly more at absolute maximum! Karotinemia to accompany my severe anemia, inability to produce iron & becoming alergic to synthetic iron within minutes of my first infusion therapy treatment, not to mention my severe reaction to & deficiency of vitamin D. Someone know something please! It was my birthday on the 14th of july & my wish was some kind of answer or assistance with even just the horrible pain this causes me from the waist down mostly, which makes every month even that much more of a struggle.for my husbamd & i. We want chidlren-i just turned 32, i really hope.someone wojld look into improving my lifee jst a bit,this has been my everything since about 2009.

    1. I have kidney disease and prone to anemia apperntly the anemia itself was making me yellow. Can you eat leafy dark leafy greens for iron? Have u had your b12 levels… Are u eating enough fats (3,6 and 9)… I’m no doctor but going on personal experience I have found the dark leafy greens and goods fats help me a lot.

  14. But Watson stated “Blueberries best be eaten because they taste good, not because their consumption will lead to less cancer.”

  15. I take Grapefruit Seed Extract 125mg capsules when I travel to 3rd world countries where I am worried I will get sick from the water or food. I understand they are antibacterial and antiviral and coat your stomach better than pepto bismo. But I have also heard they are poison to your system. I would love to know more.

  16. Dr. Greger, Are there any scientific studies showing proof of any of the “BLACK SEED OIL’ cures? Specifically the main ones like Cancer, liver health, weight loss, diabetes, better skin, infections, and hair loss? Is there any weight to the claims of this miracle oil? I tend to stay away from extracted oils anyways. Maybe chewing on the seeds might be better? Also is this plant related to Fennel, meaning having similar qualities to how fennel seeds help us with inflammation?

  17. I read your book and I became vegan again after about a ten year lapse. The only problem I appear to have is I am back to very thin nails. They break constantly into the quick. Any suggestions?

  18. Hello. my oncologist insists to undergo x-ray irradiation. Don’t know how to do, wanted to know your opinion. Remind about yourself : my name is Rita I have 2 degree of t cell lymphomas ( mycosis fungoides 2nd degree) conducted two cycles of chemotherapy without any results. On the skin of the ankles swollen with large weeping sores . Moved to vegetarianskoe diet for more than two months, every day drinking 500 ml of green juice from herbs and lemon. Drink vitamin B17 amygdalin 800 mg per day and vitamin B15. For three weeks, drink vitamins but also not , to meet you are waiting for your advice . With respect and nididhyasana for the English, translated Google

  19. This is too obvious that it is biased against natural things and supplements, just to discard their healing abilities.
    Them so-called researches must be paid and bought.
    Antioxidants from supplements are bio-identical to those found in berries, so body doesn’t recognize between them. And saying that antioxidants from nature are bad for your health is against logic and sounds as a fraud.

Leave a Reply

Your email address will not be published. Required fields are marked *

Pin It on Pinterest

Share This