Food Antioxidants and Cancer

Image Credit: Arya Ziai / Flickr. This image has been modified.

Does Antioxidant Intake Matter for Cancer?

The USDA removed their online antioxidant database of foods, “concerned that ORAC values were routinely misused by food and dietary supplement manufacturing companies to promote their products.” Indeed, supplement manufacturers got into my-ORAC-is-bigger-than-your-ORAC contests, comparing their pills to the antioxidant superfood du jour, like blueberries. We know there are lots of bioactive compounds in whole plant foods that may help prevent and ameliorate chronic disease in ways that have nothing to do with their antioxidant power, so I understand the USDA’s decision. So should we just eat lots of whole healthy plant foods and not worry about which one necessarily has more antioxidants than the other, or does one’s dietary antioxidant intake matter?

We have some new data to help answer that question. Researchers recently analyzed total dietary antioxidant capacity and the risk of stomach cancer, the world’s second leading cancer killer. A half million people were studied, and dietary antioxidant capacity intake from different sources of plant foods was indeed associated with a reduction in risk. Note that they say dietary intake; they’re not talking about supplements.

Not only do antioxidant pills not seem to help, they seem to increase overall mortality—that’s like paying to live a shorter life. Just giving high doses of isolated vitamins may cause disturbances in our body’s own natural antioxidant network. There are hundreds of different antioxidants in plant foods. They don’t act in isolation; they work synergistically. Mother Nature cannot be trapped in a bottle.

Similar results were reported with non-Hodgkin’s lymphoma: the more ORAC units we eat per day, the lower our cancer risk drops (though antioxidants or not, green leafy vegetables were particularly protective. Going from eating one serving of green leafy vegetables per week to a serving a day may cut our odds of lymphoma in half).

Should we be worried about antioxidant intake during cancer treatment, since most chemo drugs work by creating free radicals? According to some of the latest reviews, highlighted in my video Food Antioxidants and Cancer, there is no evidence of antioxidant interference with chemotherapy, and antioxidants may actually improve treatment and patient survival.

But should we take a multivitamin? See Should We Take a Multivitamin?

What about fish oil supplements? Is Fish Oil Just Snake Oil?

I recently covered how and why we should strive to eat antioxidants with every meal in an important three-part series:

  1. Minimum “Recommended Daily Allowance” of Antioxidants
  2. How to Reach the Antioxidant “RDA”
  3. Antioxidant Rich Foods With Every Meal

Preferentially getting one’s nutrients from produce not pills is a common theme in the nutrition literature. See, for example:

Antioxidants may also slow aging (See Mitochondrial Theory of Aging), reduce inflammation (See Anti-Inflammatory Antioxidants), improve digestion (See Bulking Up on Antioxidants), and help prevent COPD (See Preventing COPD with Diet). So where are antioxidants found? See my series that starts with Antioxidant Content of 3139 Foods and Antioxidant Power of Plant Foods Versus Animal Foods.

What about the role of antioxidants in other leading causes of death? That’s the subject of my video, Food Antioxidants, Stroke, and Heart Disease.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.


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.

12 responses to “Does Antioxidant Intake Matter for Cancer?

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    1. Hi Julie. Thanks for the heads up we’ll update that reference and include the one you found from 2010, href=”” target=”_blank”>USDA report.

    2. Very interesting. Thanks for the link.
      Black Raspberry 19220; Chokeberry 16062; Elderberry 14697; Wild Blueberry 9621; Blackberry 5905; Blueberry 4669; Sweet Cherries 3747; Gooseberry 3332; Goji 3290.

  1. With cancer (stage 3c ovarian–7 years), the role of ORAC in cancer inhibition is one layer of an “idea”. It appears mitochondria can become dysregulated, throw off ROS into the cytoplasm and rip up the DNA, dysregulating molecular growth pathways. Then you have the tumor microenvironment, c-cell perpetuating inflammation and angiogenesis pathways for tumor growth and survival.
    It’s not all about ORAC, though it may contribute by cooling off ROS. There are multiple inhibitors of cancer growth in food. Agarwal, et al published a great 2006 paper illustrating the effect which I often share with patients.
    I believe daily therapeutic (not culinary) doses of tumeric, ginger, brassica, pomegranate juice, berries…sprout combinations I grow, garlic, onions and purple cabbage are the main vegetables I eat due to budget.
    During chemo, I just stopped all supplements a day or 2 before and after because I do not want to help the cell kick the drug out.

    1. Oxygen Radical Absorbance Capacity – “Oxygen Radical Absorption Capacity (ORAC) assay measures the degree of inhibition of peroxy-radical-induced oxidation by the compounds of interest in a chemical milieu. It measures the value as Trolox equivalents and includes both inhibition time and the extent of inhibition of oxidation. The assay has been used to measure the antioxidant activity of foods.”

  2. Hi readers, today had on special time the creators of Cowspiracy.
    Have any of you checked the numbers they are mentioning in that documentary?
    If those numbers are anywhere near true then phew I need to rethink some points of view.

    Little bit unsure what to think right now, grasping in the dark, shine some light somebody?

  3. But what if you’re a vegan who has been told to take various “isolated” supplements like B12, Vit D & calcium and a DHA/EPA supplement to ensure no deficiencies when avoiding meat, dairy and fish? I know we’re talking about antioxidants here, but does the advice I’m hearing more and more about getting your nutrition from food, not pills, apply here?

    1. That is something that interests me also.
      Dr. Greger, when he talks about calicum, he mentions fortified foods being a source. and all the is a calcium added to almond milk for example.
      Maybe it is different because it is a mineral. and if the almond milk is going in your smoothie with heaps of other stuff like greens, fruit, berries, then it shouldn’t be a problem?

      b12 also makes me wonder also. but taking it in a pill is still the best option, when you consider all the baggage that comes with the other sources.

      John McDougall says no to vitamin D supplements. I agree with him. an excuse to make you go outside more is good anyway.

      DHA/EPA is an interesting question because I wonder about the validity of having these levels of omega 3 for health anyway. I should look more into it. Could someone send me some links? Currently, I’m just relying on chia, flax, hemp, walnut, pumpkin, sunflower seeds, and greens for omega 3, 6. Currently I’m not taking a supplement. I’d consider one after having my levels tested and they turned up on the lower end.

  4. Harvard did any interesting study when they realized vegetarians have a 70% less chance of getting cancer. (I’m not good with time but I want to say less than 2 years ago.) They were curious to what vegetarians did or not do for this spectacular percent in not getting cancer. “Leafy green vegetables,” someone concluded. They found that chlorophyll wrapped itself around the mutagen and now the cancerous cell was too large to penetrate a healthy cell. Then your body took care of it. The one thing they didn’t relate was how “leafy green vegetables” also produced an alkaline ph in one’s body. This also inhibits cancers, viruses and spoors. So, it seems it’s not just antioxidants but “leafy green” veggies – chlorophyll – with a more alkaline ph which will help prevent cancers with some potential to reverse the cancer. I do want to ask how veggies we should ingest daily. I get fresh fruit smoothies here in Thailand (they are great) and I can also get a shot of wheat grass. The promo for the wheat grass says it’s the same as eating 1.5 kg of veggies. Do I really need that much? PS: there is growing evidence that intermittent fasting prior to chemo not only ameliorates the side effects of chemo but seems to target the cancerous cells better.

    1. Daily recommendations from the USDA says 3 cups. I find that number a bit low. More fruits and veggies is always a good idea in healthy individuals.

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