Image Credit: Muffet/ liz west / Wikimedia Commons

Any update on the scary in vitro avocado data?

any updates on avocados in vivo?

Toxins  / Originally Posted in Are Avocados Bad for You?


I’m happy to report that a new study this year found avocado consumption associated with significantly reduced prostate cancer risk (a third cup of avocado a day or more associated with 60% decreased odds of prostate cancer compared to men eating less than a daily tablespoon). Holy guacamole!

image credit: Muffet/ liz west / 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.

32 responses to “Any update on the scary in vitro avocado data?

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  1. I was thinking. The original video you did said that avocado acted like chemo. So it would indeed reduce cancer… but would it not also compromise your immune system. The study said it prevented prostate cancer but did it do this by damaging the immune system like was said in the original video?

    I mean does this study prove that it is not a danger in other immune system problems, and other cancers?

    1. Same here. I remember the video saying that it in-vitro tests showed it blew DNA to pieces. I’d love to start eating it again, especially since I’m at increased risk of prostate cancer.

  2. Does anyone have any idea why “men with high linolenic acid proportions were at increased likelihood of PCa?” As an omega-3 fatty acid, isn’t linolenic acid a good thing?

    1. The “Results” section of the abstract at the “study” link above states: “high linolenic acid proportions were at increased likelihood of PCa [prostate cancer]”. But there are two forms of linolenic acid, a-linolenic which is n-3 (omega 3) and y-linolenic which is n-6 (omega 6). So, wouldn’t it make a difference which subtype is associated. Given the typical American diet, which is low in n-3 and too high in n-6, I’m wondering if these results don’t need further differentiation. But I’m posing this more as a question than an answer. I know very little about this, and I have your same a question, but the n-3, n-6 might be part of it.

  3. Ho did it go? Are there any more studies suggesting avocados are bad for us, or and research proving them to be fine to eat? DNA… All the best!

  4. Okay, well that addresses the cancer aspect, but what about during pregnancy? You’ve noted elsewhere pregnant women ought to avoid avocados. I’ve been doing the exact opposite!

    1. I follow the WFPB diet, when the warning video came out, I stopped eating avocados, but my skin and hair really suffered, after a year or two, I added them back in and my skin and hair have improved.

    1. There can be no firm conclusion. The in vitro data is concerning but food doesn’t circulate in the blood in its whole state, so we cannot know what kind of effect eating Avocado would have from that study.

  5. Reading this is 2015…is the present conclusion that avocados may damage healthy dna in vitro, but so far no negative side effects have actually been reported in humans (only positive effects)?

  6. How do they know it’s the persin, and not some pesticide in the avocado that’s causing DNA damage? Also, who eats avocado leaves? Why test them?

  7. whey protein vs pea protein vs cancer…per says “A new study shows whey protein may play a role in prostate cancer prevention.” but T Colin Campbell says dairy protein (casein) is more carcinogenic than the worst known carcionogen ( “…declaring that casein is a carcinogen that was far more powerful than aflatoxin (“the most potent carcinogen ever discovered”…)”
    Do you believe Campbell’s claim? Do you believe the study saying whey is good? If whey is bad, would pea protein have the same anti-cancer benefits without being dairy derived? Or is it specifically whey protein that fights cancer? Thanks for any clarity you can provide.

    1. I think any food isolate or concentrate is unnecessary. Whole foods are preferred. Oncology populations can differ, as survivors may not be able to eat by mouth or need additional nutrients to supplement their diet. That’s where I see the potential benefit of some of these protein powders, but I am not sure whey is the best choice? Some studies suggest whey and leucine-rich foods (meat and milk) stimulate the TOR pathway, which Dr. Greger addresses in this video. Whey protein is a highly concentrated source of animal protein, which may stimulate IGF-1 production. Similarly, concentrated/isolated soy protein supplements can also increase IGF-I. It may be that the ratio of animal to plant protein intake is important, too. Dr. Greger says in this video “Teens exposed to dairy proteins, for example, casein, skim milk, or whey experienced a significant increase in BMI and waist circumference compared to controls, whereas not a single study funded by the dairy industry found a result unfavorable to milk”

      Lastly, in a paper I wrote about cancer prevention, Applying the Precautionary Principle to Nutrition and Cancer I reference a study pointed out to me by Dr. David Jenkins about the overabundance of amino acids (Reference 46). If interested in reading more here’s a bunch of studies on whey and cancer.

  8. Dr. Greger (big fan btw!) The people and myself are still confused about avocados. I eat about 2 avocados a day so am I going to fry my DNA as suggested in your last vid on avocados in which you gave them a Harmful rating OR shall I reap the well published benefits? Love your videos but the conflicting ‘Yes’ & “No’ vids have guacafide my brain!

    1. I’m new to this site…why want the good doctor answer this question? Is it like most nutritional science…it just ain’t that easy to find a pure answer…you know its like people that are conscious of what they eat probably don’t do drugs too, so its hard to know what is really driving the results.

  9. In vitro studies like the one in the original video are pretty worthless, not video worthy most of the time. Dr. G could do a video on this more recent (April 2017!) in vivo study of avocados (The present study provides important insight regarding the acute metabolic and cardio-vascular benefits of incorporating avocados into a meal. Avocado meals improved postprandial glucose, insulin and lipid profiles with concomitant improvements in vascular reactivity):

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