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Tree Nuts or Peanuts for Breast Cancer Prevention?

Eating fiber-containing foods—especially nuts—during adolescence may significantly lower the risk of developing potentially precancerous fibrocystic breast disease (fibroadenomas).

December 31, 2012 |
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Supplementary Info

Sources Cited


Image thanks to: s58y and -Ebelien-.


That Black Women’s Health Study, which highlighted collards and carrots, was out of Boston University. Across the Charles River, the Harvard Nurse’s Health Study also tried to determine which plants were particularly protective in reducing breast cancer risk, and they identified nuts. The intake of fiber and nuts during adolescence and incidence of proliferative benign breast disease, such as fibrocystic breast disease, fibroadenomas—noncancerous breast lumps—but is considered a marker for increased breast cancer risk. Depending on what biopsies show it could indicate anywhere from 30% to 1300% greater risk of going on to develop cancer. Breast cancer can take decades to develop, so they wanted to start early, asking women what their diets were like in high school. Now in adults it's clear, as you can see in this 2012 review, the more fiber you get in your diet the lower your risk of breast cancer… And same thing, apparently, when you're younger. Women who had the most fiber intake during adolescence have a 25% lower risk of this potentially precancerous breast disease. But there’s fiber in fruits, vegetables, beans, whole grains, nuts, seeds—all whole plant foods. Did any class of plant foods stick out? Nuts was found to be particularly protective. Two servings a week was associated with a 36% lower risk, but that raises the question, which type of nuts? Like peanut butter and jelly sandwiches or do you have to eat true nuts, like almonds, pecans, walnuts, that sort of thing. Just tree nuts, or peanuts as well? And the answer is both. Compared to those who rarely ate nuts, those eating just one or two handfuls a week during high school appeared to drop risk around 30%, “In summary, their study observed significant inverse associations between adolescent dietary intake of fiber and nuts and risk of proliferative benign breast disease. Our results provide supportive evidence of the important role of dietary exposures during a unique period in a woman’s life in the earlier stage of breast carcinogenesis, the early stage of breast cancer development. These findings, if corroborated, may suggest a viable means for breast cancer prevention.”

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Jonathan Hodgson.

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Dr. Michael Greger

Doctor's Note

Harvard also found that fiber and nut consumption was associated with a significantly longer lifespan in women. See What Women Should Eat to Live Longer. Soy consumption during adolescence also seems particularly protective. See Thursday's video Why Do Asian Women Have Less Breast Cancer?. The reference to the Black Women’s Health Study was referring to Friday's video-of-the-day Preventing Breast Cancer By Any Greens Necessary. What effect might even just a few weeks on a diet full of plants have on breast cancer cell growth? See Answer to the Pritikin Puzzle. Don't nuts make you fat, though? You'd be surprised—see Nuts and Obesity: The Weight of Evidence.

Please also check out my associated blog posts  for more context:  Go Nuts for Breast Cancer Prevention and Breast Cancer & Alcohol: How Much Is Safe?

If you're thinking, wait, wasn't this yesterday's video? Alas, in 2013 I'm dropping down to just new videos every Monday, Wednesday, and Friday--see my email newsletter this morning (and feel free to subscribe if you haven't already).


  • Sheila Tajima-Shadle

    I just shared this with my 15 year old daughter and she just tried her first pistachio….Thank you Dr Greger!

  • HemoDynamic, M.D.

    I’m nuts about healthy breasts!
    (Comon’ lighten up)

  • Anders

    Dr Greger!

    Is there a way to secure all your protein from raw sources, that is without eating any cooked legumes? With the raw vegan movement going strong, I feel this would be a relevant topic for you to address in an upcoming video.

    Keep up the amazing work!

    • sheof

      yes, check out the 8/10/10 diet.

  • Erin W

    Hi Dr. G,

    This is a bit off topic, but I just happened to come across a podcast featuring an interview with Susan Schenck, author of “Beyond Broccoli, Creating a Biologically Balanced Diet When a Vegetarian Diet Doesn’t Work.” She claimed that going vegan made her terribly sick because all of the nuts and seeds caused her to gain weight and she ended up with a number of severe deficiencies caused by excluding meat from her diet. I saw your videos about nuts not contributing to weight gain in recent studies. But, could you shed some light on some of her other claims? She said that long term vegans will usually end up with DHA, B12, and Carnitine deficiencies because they can not be absorbed well from plant sources or the body will not make enough of it. She also says that Vitamin K2 and Vitamin A are not converted well from plant sources and we must get those things from animal products. Her claim was that vegan diets will only work long term for very few people with very heavy and expensive supplementation. What are your thoughts on those claims? Is there any evidence to back them up?

    • Lynda

      Any studies out there about this? I’m wondering too but so far I’m happy on my vegan diet but without nuts I wouldn’t be able to do it.

      • Erin W

        All the videos on this website seem to make it clear that nuts are super healthy and the calories do not contribute to weight gain the same way calories from other foods do. I just want to know if all that other stuff she claims has any studies to back it up. I have been an ovo-vegetarian for about 6 years (I only eat about 1 egg a week) and I want to make sure that I am getting all of the nutrition I need because I plan to stay on this diet for life and I am only in my late 20′s.

        • Chelsea Nordick

          I am almost on the same diet as you, and am also in my late 20s. This website has been so helpful for me! Dr. Gregor does say in a few videos that B-12 is a necessary supplement, but if you are eating properly it should be the only one you need to take. I live in Sweden, where the sun disappears for half of the year, so I need to take vitamin D as well. I’ve been eating like this for awhile, with regular nut consumption and I haven’t gained weight or developed any crazy deficiencies. I think you just need to be mindful of what you eat, and it should be fine. A lot of people write books about nutrition, but I think that nutrition backed up with scientific studies is much more reliable.

  • LynnCS

    Hi Dr. Gregor…I really love all your videos and can only imagine how much research goes into bringing them to us. I wish one thing with this one and that is that you would picture raw, unfried, unsalted nuts so as to not encourage the use of frying, oil, and salt as a standard. Meantime, I love the article. It certainly turns around what I have thought so far.

  • Tan Truong

    Nuts for nuts!

  • Assist the Principal

    Any studies on teens who are allergic to nuts and breast cancer rates?

    • Don Forrester MD

      I couldn’t find any studies addressing your specific question. However there is evidence that female children and teens who consume 2 servings of soy a day decrease breast cancer rates as adults. Early puberty is associated with increased breast cancer and is associated with meat and animal protein intake but soy consumption delays onset of puberty see Obesity has been associated with increased breast cancer. Fruits and vegetables and fiber have been associated with less breast cancer. Some of the substances in nuts which might explain the lower incidence of breast cancer such as ellagic acid and phytosterols are also present in other plant foods. So even with an allergy to nuts there are ways to lower the risk of breast cancer not to mention the many other chronic diseases best avoided.