Doctor's Note

What about antioxidants and cancer? That was the subject of my last video Food Antioxidants and Cancer.

Which foods have the highest antioxidant content? See:

It’s the heme iron in chicken blood that's implicated in fat oxidation in the stomach. That’s one of the targets of the Meat Additives to Diminish Toxicity.

More on reducing stroke risk can be found in my videos Preventing Strokes with Diet Whole Grains May Work As Well As Drugs.

I have more than 150 videos on heart disease. Heart Disease Starts in Childhood and One in a Thousand: Ending the Heart Disease Epidemic are among two of the most recent.

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  • Patti

    I read an article the other day about a group of natives who in spite of being older than the comparison group and eating way more salt, don’t get high blood pressure, have a ninth the amount of heart disease and one-fifteenth the amount of cancer. These guys do eat fish but mostly have a vegan diet. It seems that their good health is due to drinking 4 to 5 cups each day of a drink they make from boiled ground raw cocoa beans and banana which they strain before drinking. I compared it the organic cocoa powder I use and found that mine has no more than one-sixth the flavonol (antioxidant) content of theirs. And of course I don’t use nearly as much or even use it daily. I’d love to hear more about this!

    • DGH

      How do we know that it’s the Kuna cocoa drink that extends their longevity? Surely there are so many other factors at play – their communal/tribal structure, their low levels of mental illness, their constant exposure to sunlight, their living near a semi-aquatic environment, other dietary factors, physical exercise, childrearing practices, genetics. To say it’s all got to do with this one drink that they consume….

      • Patti

        Good Questions, DGH! We certainly should ask this sort of thing whenever a study comes out for a particular indigenous culture. Digging a bit deeper, I found numerous studies which support this effect in cultures other than in the Kuna, both epidemiological and clinical. Pubmed for example lists too many studies to mention. Some of the benefits of cocoa in them include prevention of preeclampsia, of cardiometabolic disorders, of insulin resistance, obesity, vascular dysfunction, depression, gingivitis, Alzheimers, diabetes, glaucoma, cataracts, inflammation. It increased good cholesterol, antioxidants in the blood and protected the skin from sunburn. Plus there was confirmation of its protective effects I mentioned above, against heart disease,high blood pressure and the big C. But cocoa isn’t the only food with flavanols, although it may be one of the best:

        Flavanol Content, mg/kg or mg/L








        Green tea

        Black tea

        Red wine


        Finally, I want to comment that we can do even better than the Kuna by following Dr. Greger’s recommendations. We can avoid their consumption of salt, eat the 5 servings of fruits that they consume daily, but include berries, citrus and apples; each day have some mushrooms or nutritional yeast, cruciferous vegetables, greens, tea, beans, garlic and onions, flax, vitamin D and B-12 and of course, avoid the mercury and toxin-laced fish flesh.

  • Gina

    Not directly related to this, idk where to ask this. Does drinking high antioxidant drinks (like green tea or hibiscus tea) out of metal (stainless steel or aluminum) affect the amount of antioxidants and other phytochemicals that are available as opposed to drinking from glass or ceramic. Also the same for drinking cold beverages out of plastic (bpa free, never hot drinks of course). Thank you.

    • Darryl

      I’d expect a negligible effect on polyphenol intake (a preferable term to antioxidant, as these plant compounds aren’t functioning primarily as direct antioxidants in vivo). Aluminum has been associated with neurodegenerative disease, so it may be prudent to avoid cooking or serving acidic foods (ie tomatos, citrus etc) in aluminum vessels.

  • Arun Mukherjee

    I have been reading about cooking oils harming the endothelial layer and leading to oxidative stress etc. What do you think of cooking with oil, Dr. Greger?

    • Tommasina

      @arunmukherjee:disqus I’ve heard a lot about that also. Dr. Greger seems to recommend against using extra virgin olive oil: and coconut oil . I’m sure I’ve seen him recommending sauteing veggies with water but I haven’t been able to find it again. Anyways, hope that helps!

      • DGH

        I eat these oils in moderation, mainly in the form of whole nuts/seeds, a little bit of canola oil in some hummus, and a tablespoon of tahini per day in a salad, but I don’t cook or oxidize any cooking oils in my diet. I think the harms of cooking oils are somewhat overblown, but I remain conservative and cautious about their use.

      • Arun Mukherjee

        Thank you Tommasina. I just watched the two videos. They are very helpful. But could we also have one that addresses the issue head on?

    • Marc S

      Oil is a processed food and like other processed foods may actually be harmful.

      • Mack

        You need fat to help absorb carotenoids. Maybe, DHG has got the right idea, eating them in a natural unprocessed form. But I’d avoid the canola and substitute fresh avocado instead.

        • Toxins

          Most plant foods contain sufficient quanitites of fat to be absorbed. From Jeff Novick:

          Absorbing more doesn’t automatically equate to better health outcomes.

          Speaking of health outcomes, which is what really matters, lets put all of this into proper perspective.


          “‘Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids’, Food and Nutrition Board. Institute of Medicine. National Academy Press, Washington D.C. Pp. 343-344 (2000)”

          “These data, although in varying populations, suggest that 3 to 6 mg/day of β-carotene from food sources is prudent to maintain plasma β-carotene concentrations in the range associated with a lower risk of various chronic disease outcomes (see Table 3).”

          Table 3:

          As just detailed, plasma and tissue concentrations of carotenoids have been associated with a variety of health outcomes; that is, higher concentrations are associated with a lower risk of cancer, coronary heart disease, and all-cause mortality. This could be used as a possible indicator for establishing requirements for carotenoids. However, the limitation of this approach is that it is not clear whether observed health benefits are due to carotenoids per se or to other substances found in carotenoid-rich foods.

          Thus, these data are suggestive of prudent intake levels, not required levels of intake. Recommendations have been made by a number of federal agencies and other organizations with regard to fruit and vegetable intake. Nutrient analysis of menus adhering to the U.S. Dietary Guidelines and the National Cancer Institute’s Five-a-Day for Better Health Program, for example, indicates that persons following these diets would be consuming approximately 5.2 to 6.0 mg/day provitamin A carotenes on average if a variety of fruits and vegetables were consumed (Lachance, 1997). Similar levels would be obtained by following Canada’s Food Guide for Healthy Eating which specifies a minimum of five servings of vegetables and fruit (Health Canada, 1997). Other food-based dietary patterns recommended for the prevention of cancer and other chronic diseases would provide approximately 9 to 18 mg/day of carotenoids (WCRF/AICR, 1997).

          NOTE: this is 3-6x the amount recognized as being enough to lower disease risk

          It is also based on the WCRF/AICR report from 1997. In many other discussions here, I have quoted the WCRF/AICR newest report from 2007 saying that they now more than ever, recommend dietary “patterns” over recommending specific “individual foods”.

          So, in other words, if Americans would just get in the recommended amounts of fruits and veggies, it would not only provide carotenoids, but more than enough of all of them to produce the beneficial health outcomes, including reduced risks of cancer. And anyone following a Whole Food plant based diet, as recommended here, would already be consuming WAY more than enough.

          Of course, the real issue is why do you have to increase the absorption of raw veggies (which are very low) when you can just eat tubers, which have almost the highest absorption rate, as is.

  • guest

    Dr. Greger, I have been reading a bit about the negative effects of saponins on increasing the permeability of the intestines. This really concerns me since I have lots of food intolerances and I do eat grains and beans, and these seems to be known to contain saponins. I am 100% vegan and have been for many years. But my diet seems to consist of lots of foods that even many vegans out there seem to avoid for just this issue I have inquired about here. Thank in advance for any comments on the merits of this study, and whether you feel that the saponins in plants and grains and beans can, when eaten as a large part of the diet, make the gut “leaky”/permeable.

    • Larry Hathaway

      Dr Greger, should antioxidants be evenly distributed in meals: instead of my adding frozen berries, amla and Goji berries to my morning oatmeal, should the amla be added to lunchtime kidney beans instead? If there is a high nominal antioxidant level in any given meal, will the last incremental antioxidants be less efficacious?

      • Lisa W

        Kidney beans have plenty of their own antioxidants; not so with oatmeal. But it sounds like you a a terrifically healthy diet.

  • Guest

    Does a high fruit-sugar diet cause the liver to dump fat into the blood? I am considering reducing excessive fruit consumption based on some Doctors claiming that high fructose containing whole fruits can actually contribute to fat in the blood. Such a weird concept for me to get my mind around but apparently it has to do with the liver converting glucose to fat, then pumping it out into the body. One ends up getting heart disease even on an extremely low-fat diet. So odd but apparently true. What do you think?

    • Cary

      Sounds like Paleo-freak propaganda. Another Doctor, claims that sugar is poison, but that fruit also contains the antidote in the form of fiber which slows its absorption so it won’t cause spikes in the blood.

    • Anectdotal: I now eat lots of fruit compared to my prior veg-junk-tarian diet. My triglycerides (fat in the blood) are down to 62 from nearly 400.

      As long as one is not gaining weight from eating an excess of calories, sugar in fruit is not generally a problem for non-diabetics.

  • Nicolas1

    I will take care of everything now !

    granite kitchen worktops

  • Peter S.

    When you talk about strokes and preventing strokes are you talking about both hemorrhagic (bleeding) AND ischemic (blockage) strokes? I understand the vast majority of strokes are ischemic, but I wonder whether someone who has had a hemorrhagic stroke is equally well served by a plant based diet.

  • Michel Voss

    Too many informations in one video, too long comments.

  • Wonderful video! Thanks. We like lots of info!

  • Annetha

    Interesting: for mouse strain with two characteristics of human metabolism–

    the lack of endogenous ascorbate (vitamin C) production and the expression of Lp(a),

    the latter a leading risk factor for cardiovascular disease–

    vitamin C in drinking water sufficient to raise blood levels to normal (wild mouse) levels

    inhibited chronic hypoascorbemia and complete depletion of ascorbate (scurvy),

    which lead to Lp(a) accumulation in the vascular wall (atherosclerotic lesion development)

    in mice that didn’t receive C-laced drinking water.

    “…study design mimics important events during the evolution of man. After the loss of endogenous ascorbate synthesis, the survival of our ancestors was repeatedly threatened through epidemics of scurvy. Individuals expressing Lp(a) may have had an evolutionary advantage by effectively counteracting hemorrhagic blood loss through a scurvy-impaired vascular

    Cha et al, 2015. Hypoascorbemia induces atherosclerosis and vascular deposition of lipoprotein(a) in transgenic miceAm J Cardiovasc Dis. 2015; 5(1): 53–62.