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What to Eat and Avoid for Women with BRCA Gene Mutations

Five studies have been performed on breast cancer survival and soy foods involving more than 10,000 breast cancer patients, and together they found that those who eat more soy live longer and have a lower risk of the cancer coming back. What about women who carry breast cancer genes? Fewer than 10 percent of breast cancer cases run in families, but when they do, it tends to be mutations to one of the tumor suppressor genes, BRCA1 or BRCA2. BRCA 1 and BRCA 2 are involved in DNA repair, so if either one of them is damaged, chromosomal abnormalities can result, which can set us up for cancer. I examine this in my video Should Women at High Risk for Breast Cancer Avoid Soy?.

This idea that we have tumor suppressor genes goes back to famous research from the 1960s that showed that if we fuse together a normal cell with a cancer cell, rather than the cancer cell turning the normal cell malignant, the normal cell actually suppresses the cancerous one. Tumor suppressor genes are typically split into two types: gatekeeper genes that keep cancer cells in check and caretaker genes that prevent the cell from becoming cancerous in the first place. BRCA genes appear able to do both, which is why their function is so important.

Until recently, dietary recommendations for those with mutations to BRCA genes focused on reducing DNA damage caused by free radicals by eating lots of antioxidant-packed fruits and vegetables. If our DNA repair capacity is low, we want to be extra careful about damaging our DNA in the first place. But what if we could also boost BRCA function? In my video BRCA Breast Cancer Genes and Soy, I showed how, in vitro, soy phytoestrogens could turn back on BRCA protection suppressed by breast cancer, upregulating BRCA expression as much as 1,000 percent within 48 hours.

Does that translate out of the petri dish and into the person? Apparently so. Soy intake was associated with only a 27 percent breast cancer risk reduction in people with normal BRCA genes, but a 73 percent risk reduction in carriers of BRCA gene mutations. So, a healthy diet may be particularly important for those at high genetic risk. Meat consumption, for example, was linked to twice as much risk in those with BRCA mutations: 97 percent increased risk instead of only 41 percent increased breast cancer risk in those with normal BRCA genes. So, the same dietary advice applies to those with and without BRCA mutations, but it’s more important when there’s more risk.

What about women without breast cancer genes or those who have already been diagnosed? See my video Is Soy Healthy for Breast Cancer Survivors?.

What is in meat that may increase risk? See:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:


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.

19 responses to “What to Eat and Avoid for Women with BRCA Gene Mutations

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  1. Soy intake was associated with only a 27 percent breast cancer risk reduction in people with normal BRCA genes, but a 73 percent risk reduction in carriers of BRCA gene mutations.

  2. Very interesting information.

    I wondered if you have nutritional information regarding the PALB2 gene which is fairly rare and only just started being tested for. I and some of my family have been diagnosed with following breast cancer diagnosis.

    Does this work in the same way as the BRCA1/2 I believe there is some link to BRCA2?

    1. Louise Hepworth,

      I doubt that the information you are looking for is available. I’d never heard of this mutation, and I’ve been diagnosed with breast cancer (2014) and have a very strong family history of it. And we don’t have the BRCA mutations. (Or at least not the older ones.)

      “However, prospective data related to the clinical outcomes of PALB2 mutation carriers is lacking and very little information (beyond mutation penetrance) is available to guide current clinical management for carriers (affected and unaffected by cancer).“. (published in 2016)

      It sounds as though very little is even known about how to specifically treat this type of cancer (or women who have this mutation), so I’m guessing that there are no nutrition studies about it. Such studies generally take a long time, if they’re done at all. And nutrition science seems very broad brush to me: general principles may be understood, but not so much about details.

      But you could probably research this online; one good suggestion I read was to type the abbreviation “nih” after your search terms to bring up more original research articles.

  3. Thank you very much for clarifying this. I had been waiting for confirmation that it is safe for that population. What type of soy foods were used in the studies?

  4. Please be specific about what soy foods. Soy lecithin is in EVERYTHING in the uS even chewing gum. My homeopath told me to avoid soy at all cost! So I have for 7 years. The best I could anyway. So what soy should I eat to live longer be specific. This is my live and this is to vague!

    1. Karen,

      Soy lecithin is a glycerolipid from soybean oil, phosphatidylcholine. It’s purified from soybean oil, and used as an emulsifier. Since it’s a highly processed product, it Is highly unlikely to contain any other soybean components.

      And I recall Dr. Greger saying, in a video on this topic, that if your doctor tells you to avoid soy products (because you’ve been diagnosed with breast cancer), then you know that doctor hasn’t opened a nutrition textbook or kept up with the research over the past several (10?) years.

      And I would never trust a homeopath. As far as I understand it, they have little to no scientific training. Homeopathy is a basically a flight of fancy with very little basis, and it is physically, chemically, and biologically implausible to have any effect at all, other than the placebo effect.

      You could look at the videos on this site about soy food, and if you desire to proceed further, read the nutrition science research and other research papers on which the videos are based (the list of sources cited are provided, with links to at least the abstracts if not the entire publications), and make up your own mind as to whether soy food is to be avoided. At least that way, you’d be more up to date and knowledgeable than your homeopath.

    2. Karen,

      I will add to Dr. J’s comment that your doctor is right about avoiding soy lecithin, but edamame, tofu, tempeh and miso and soy milk can be over on the other list.

      Yes, choose organic, nonGMO.

      Yes, don’t eat all the processed soy fake meats and powders out there.

      Dr. Greger has videos on not eating too many servings per day and that is the other limiting factor.

      Mostly, if you eat too many servings it erases the benefits by increasing IGF-1.

      His video speaks about that.

      There are things like soy sauce that you don’t want to eat because of too high sodium content, but he has a video that Miso is okay and the Miso packages have health benefits posted on them.

      The salted soy sauces are because of stroke risk that showed up in Japanese people which was reversed when they lowered their sodium intake.

      If you are worried about breast cancer, watch his soy and breast cancer videos and under the videos are the links to the studies.

      I wish I could give you a hug because I have read the soy logic from both sides and I know that it is so scary when one side tells you that soy will kill you and one side tells you that soy will save your life.

      But I couldn’t give you a hug during coronavirus anyway, so please accept this virtual hug.

      My mother died young of breast cancer and soy was one of those confusing topics.

      It is less confusing once you understand the estrogen receptors and how soy affects IGF-1 at too high a dose, but not at a low dose.

  5. Women who have their first baby in their 20s and breastfeed for AT LEAST a full year, but preferably much longer, and especially if they have a second baby (also extended nursing) have low rates of breast cancer. Highest rates are women who do not have a baby, second highest, have first baby at 40, 3rd highest, first baby in 30s and for all three of these categories higher rates associated with no history of breast feeding. Also menstrual history plays a role: late first period, and early last period (early menopause) are linked with higher rates of breast cancer. Hunter & gatherer people (from whom every person evolved) tend (even today) to have first period at 17 and menopause in 40s (rather than 50s) They have 2 or 3 children, and breast feed for 2-3 years. They had a diet vastly different than most modern women, and they were very active. This has been studied and documented. Doctors do not share this info. with their patients.

  6. Question: Do high levels of Vitamin C (by supplement) cause kidney damage? I know that we can only absorb a few hundred milligrams at once. The joke in among people who study nutrition is that taking high dose Vit.. C is paying for very expensive urine.Seems that since kidneys filter urine, that too much C may harm them.

  7. I have been tested and told I have a soy allergy, testing very high on the scale. I am sure I ingest soy without knowing it and had for years before being told after being tested for a number of possible allergies. Should I try to eat soy for health benefits? I have never had an anaphylactic reaction or any noticeable allergic reaction that I ever could attribute to soy-containing foods. Do you think the benefits outweigh the risks? I am a woman who was unable to have any children, but no known breast cancer has been noted in any of my close relatives.

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