Doctor's Note

For more videos on phytonutrient antioxidants, see:
Minimum “Recommended Daily Allowance” of Antioxidants
The Fruit Whose Juice Is Healthier

And check out my other videos on antioxidants

For more context, check out my associated blog posts: Açaí to Zucchini: antioxidant food rankings, and Strawberries Can Reverse Precancerous Progression.

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  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on antioxidants. Also, there are 1,449 other subjects covered in the rest of my videos–please feel free to explore them as well!

  • hsroex

    I found an interesting article on strawberries and it is overwhelming to see how many different nutrients and phytochemicals are present in just a strawberry, even a decent amount of fiber.
    Enjoy the berry and the article :)

    • Toxins

       Thanks for the great link!

  • Guest

    I’ve found some articles online citing this study, I think, from Kansas State. The articles claim this study says that too many antioxidants can be a BAD thing. Thoughts?

    • Toxins

      Keep in mind this study was done with rats, not humans and the antioxidants were supplemented, and not obtained through food. As of now, we know that humans need as much antioxidants as one can consume through diet and there are only benefits that come along with a high antioxidant diet.

      • Guest


        • GilbowH

          I am curious of any negative effect of  Red Drink Powder sold by Trader Joe’s. It is a concentration of 51 dried fruits, seeds, berries etc. No supplements or chemicals added. It has many times the anti-oxidants score that is found on ORAC. I have not been able to determine who the producer is. Does anyone have any info on this ?

          • gr

            It’s always best to stick to whole plant foods. They are always much cheaper and better for you. We don’t know if they pasteurized the mixture after making it which causes the a lower orac and not to mention orac isn’t the only thing fruits and veggies have. They have fiber which is what allows you to feel satiated throughout the day.

    • gr

      Notice how they don’t feed the mice actual whole food . Also notice how they are using vitamin C which is known to cause a pro oxidant effect at high levels. These scientists should already know that isolating one chemical and giving x a huge does of just that one chemical will usually have a negative effect or at the maximum have a positive effect with a bunch of side effects as seen with big pharma.

  • pprender

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

  • Derrek

    Can you eat too many fruits in a day or at a time? I heard eating large amounts of fruit causes your liver to store some as fat. Is this true? I just didn’t want to eat too many fruits at one time if it had negative effects.

    • Toxins

      The fibers in fruit allow fructose to be slowly drawn to the liver so it is not overwhelmed all at once. Eating a lot of fruit is not a concern.

    • Kevin

      Bodyfat storage occurs when you take in more energy than your body is using. If you eat fruit it’s not digested immediately despite the sugar content. It has fiber and phytonutrients to slow down the digestion. This shouldn’t be a problem since all your cells run on sugar so it will likely be using the sugar as energy rather than storing it as fat. Fruit is not that calorically dense so it would be hard to eat more than what your body can use.

  • Derrek

    I get a yeast smell and don’t eat hardly any processed food. Just fruits and veggies. Should I lay off the fruit or what else would you recommend as I’m vegan and eat lots of veggies? I also have dandruff. Any advice?

    • Lawrence Woodhams

      I have the same problem for the last year. I think it started when I bought a used car that was from the pacific northwest. It had a funny sweet yeasty moldy smell, crushed potato chips on the floor and mold on the ceiling. I used my ozone generator to kill everything living in it but I drove it home first and breathed that nasty spore into my sinuses. I use Hydrogen peroxide at about .75 (less than 1) percent as an irrigation (with nelli med irrigation bottle, and their saline packet), every day or so to knock down the smell. It never completely goes away though.

  • breffni

    Dr. Greger, please comment on this latest article of the possible adverse effects of too much antioxidants

  • Eric Salisbury

    Well that is wonderful news! :)

  • PlantPoweredTrainer

    I wonder if with all the new developments in research this idea needs to be revisited.. For example, they tested up to 4 cups of stawberries and saw an increase. We now know the antioxidant content of over 3100 foods. Based on that study and others I have pieced together a morning smoothie that is insanely oxidant rich: 1 C Spinach, 1 C Kale, 1 C Arugula, 1 C Blueberries, 1 C mixed red berries, 1 banana (I like the taste!), 1 C Broccoli florets, 1 T flax, 1 T chia, 1 t Dulse, 1 t Amla powder,dash of cinnamon, cloves, ginger, and turmeric. Blend and consume for breakfast. Obviously a meal like this is light years beyond 4 cups of strawberries. I wonder if there is any research into these huge mega dose antioxidant smoothies and juices that are becoming popular? Especially with the emergence of super antioxidant rich foods like Amla, Clove, Acai, and such. I worry sometimes that these mega rich doses may have a reversed effect such as is seen with mega doses of vitamin C in pill form, or at least that much of the nutrition (and food cost) is wasted. I have started consuming my smoothie over the course of the day to try to err on the side of caution in regards to these concerns. So I’ll have something extra for breakfast like a small bowl cold quinoa with almond milk and berries and nut sprinkled on top and some spices (cinnamon, clove, allspice) and drink about a third of my smoothie. Then I will consume the rest throughout the day with and inbetween meals.

    • George

      Since there are almost 2 years since you started drinking that smoothie, maybe you can tell us your impressions. Any side-effects? I know, we can’t draw many conclusions based on a study with the sample size 1, but still… :)