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.

Goes 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:

Lowering Your Cancer Risk by Donating Blood

Back in the early 1980s, a pathologist in Florida suggested that the reason premenopausal women are protected from heart disease is that they have lower stores of iron in their body. Since oxidized cholesterol is “important in atherosclerosis, and oxidation is catalyzed by iron,” might the lower iron stores of menstruating women reduce their risk of coronary heart disease? “The novel insight suggesting that the longevity enjoyed by women over men might relate to the monthly loss…of blood is remarkable,” but is it true? I discuss this in my video Donating Blood to Prevent Heart Disease?.

The consumption of heme iron—the iron found in blood and muscle—is associated with increased risk of heart disease. Indeed, “an increase in heme iron intake of 1 mg/day appeared to be significantly associated with a 27% increase in risk of CHD,” coronary heart disease. But, heme iron is found mainly in meat, so “it is possible that some constituents other than heme iron in meat such as saturated fat and cholesterol are responsible” for the apparent link between heme iron and heart disease. If only we could find a way to get men to menstruate, then we could put the theory to the test. What about blood donations? Why just lose a little blood every month when you can donate a whole unit at a time?

A study in Nebraska suggested that blood donors were at “reduced risk of cardiovascular events,” but another study in Boston failed to show any connection. To definitively resolve the question, we would really have to put it to the test: Take people at high risk for heart disease, randomly bleed half of them, and then follow them over time and see who gets more heart attacks. Maybe it could turn “bloodletting” from the past into “bleeding-edge technology.” In fact, that was actually what was suggested in the original paper as a way to test this idea: “The depletion of iron stores by regular phlebotomy could be the experimental system for testing this hypothesis…”

It took 20 years, but researchers finally did it. Why did it take so long? There isn’t much money in bloodletting these days. I suppose the leech lobby just isn’t as powerful as it used to be.

What did the researchers find? It didn’t work. The blood donors ended up having the same number of heart attacks as the non-donor group. Something extraordinary did happen, however: The cancer rates dropped. There was a 37 percent reduction in overall cancer incidence, and those who developed cancer had a significantly reduced risk of death. An editorial in the Journal of the National Cancer Institute responded with near disbelief, saying the “results almost seem to be too good to be true.” “Strikingly,” they started to see cancer reduction benefits within six months, after giving blood just once. As the study progressed, the cancer death rates started to diverge within just six months, as you can see at 2:46 in my video, but this is consistent with the spike in cancer rates we see within only six months of getting a blood transfusion. Is it possible that influx of iron accelerated the growth of hidden tumors?


I continue this wild story in my video Donating Blood to Prevent Cancer?.

What if you feel faint when you give blood? Don’t worry. I’ve got you covered. Check out How to Prevent Fainting.

What might iron have to do with disease? See The Safety of Heme vs. Non-Heme Iron and Risk Associated with Iron Supplements.

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:

What Happens When Pregnant Women Eat More Animal Protein

Are high-protein diets during pregnancy healthful or harmful? That question was answered about 40 years ago in the infamous Harlem Trial of 1976: a “randomized controlled trial of nutritional supplementation pregnancy, in a poor black urban population in the United States.” The study, which I discuss in my video The Effect of Animal Protein on Stress Hormones, Testosterone, and Pregnancy, “was begun when protein was commonly assumed to be deficient in the diet of the poor.” Had researchers actually analyzed their diets before they started, they would have realized that this wasn’t true, but why let facts get in the way of assumptions? So, the researchers split poor black pregnant women into three groups, each receiving one of the following treatments: (1) an extra 40 grams of animal protein a day, which is essentially a couple cans of Ensure, (2) an extra 6 grams of animal protein, or (3) no extra protein. Then they sat back and watched what happened. The high-protein group suffered “an excess of very early premature births and associated neonatal [infant] deaths, and there was significant growth retardation” in the babies who survived. More protein meant more prematurity, more deaths, and more growth retardation, which you can see reflected in the chart at 1:00 in my video.

What’s more, animal protein intake during pregnancy has been associated with children becoming overweight later in life and getting high blood pressure. The “offspring of mothers who reported eating more meat and fish had higher systolic blood pressure” in adulthood. This was part of another failed dietary intervention trial in which mothers were advised to eat a pound of meat a day. The increased weight gain and high blood pressure may be due to the obesity-causing chemical pollutants in the meat supply, as I’ve discussed in my video Animal Protein, Pregnancy, and Childhood Obesity, or the animal protein-induced rise in the growth hormone IGF-1. Or, it could be due to a steroid stress hormone called cortisol.

As you can see in the chart at 2:01 in my video, a single meal high in animal protein can nearly double the level of the stress hormone in the blood within a half hour of consumption, much more than a meal closer to the recommended level of protein. When subjects are given a meal of crab, tuna fish, and cottage cheese, the stress hormone level shoots up. If they’re instead given some barley soup and a vegetable stir-fry on rice, the stress hormone level goes down after the meal, as you can see at 2:27 in my video. Imagine eating meat-fish-dairy meals day after day. Doing so “may chronically stimulate” our stress response axis “and increase the release of vasoactive hormones” that could increase our blood pressure. And, all that extra cortisol release has been linked to increased risk for elevated blood levels of insulin, triglycerides, and cholesterol.

When men on a high-protein diet, “such as meat, fish, poultry, egg white,” were switched to a high-carb diet of bread, vegetables, fruit, and sugary junk, their cortisol levels dropped about a quarter within 10 days. At the same time, their testosterone levels shot up by about the same amount, as you can see at 3:09 in my video. High-protein diets suppress testosterone. That is why, if men eating plant-based diets begin to eat meat every day, their testosterone levels go down and some estrogens actually go up, and that’s why bodybuilders can get such low testosterone levels. It’s not the steroids they’re taking. If you look at natural bodybuilders who don’t use steroids, there is a 75 percent drop in testosterone levels in the months leading up to a competition. Testosterone levels were cut by more than half, which is enough to drop a guy into an abnormally low range, as you can see at 3:47 in my video. It’s ironic that they’re eating protein to look manly on the outside, but it can make them less and less manly on the inside. And, from an obesity standpoint, in general, a drop in testosterone levels may increase the risk of gaining weight and body fat. What does cortisol have to do with weight?

There’s actually a disease caused by having too much cortisol, called Cushing’s syndrome, which can increase abdominal obesity. Even in normal women, though, chronic stress and chronic high cortisol levels can contribute to obesity. What’s more, if they’re pregnant, high-meat and low-carb diets may increase cortisol levels in the moms, which can lead to inappropriate fetal exposure to cortisol, which, in turn, can affect the developing fetus, resetting her or his whole stress response thermostat and leading to higher cortisol levels in later adult life. This can have serious, life-long health consequences. Every maternal daily portion of meat and fish was associated with 5 percent higher cortisol levels in their children as much as 30 years later, though green vegetable consumption was found to be protective. Higher meat consumption, such as three servings a day compared to one or two, was associated with significantly higher cortisol levels, but eating greens every day appeared to blunt some of that excess stress response, as you can see at 5:12 in my video.

As well, the adult children of mothers who ate a lot of meat during pregnancy don’t only have higher stress hormone levels, they also appear to react more negatively to whatever life throws at them. Researchers put them through the Trier Test, which involves public speaking in front of a panel of judges, following by a live math exercise. You can see in my video at 5:36 a chart comparing the stress hormone responses in those whose moms ate less than two servings of meat per day, about two servings a day, or about two to three servings a day. Note that before the test started, the cortisol levels of the two groups eating less meat started out about the same, but their exaggerated cortisol response was laid bare when exposed to a stressful situation. The real-world effects of this are that after that sort of test, when people are given their own private snack buffet with fruits and veggies versus fatty, sugary, comfort foods like chocolate cake, guess who may eat less of the fruits and veggies? Those who have high chronic stress levels. “Cortisol has been implicated as a factor in motivating food intake” even when we aren’t really hungry.

It’s no surprise then that a woman’s animal protein intake during pregnancy may lead to larger weight gain for her children later in life—and maybe even for her grandchildren. “Remarkably, recent evidence suggests that the long-term consequences of adverse conditions during early development may not be limited to one generation, but may lead to poor health in the generations to follow, even if these individuals develop in normal conditions themselves.” Indeed, the diet of a pregnant mother may affect the development and disease risk of her children and even her grandchildren. Ultimately, these findings may shed light on our rapidly expanding epidemics of diabetes, obesity, and heart disease.


Whoa, there was a lot to unpack! Rather than break it up, since so much of it was tied together, as you could see, I compiled everything into this one, heftier piece. You may want to read this a second time and watch the video to absorb it all.

For more on how a woman’s diet during pregnancy can affect her children, see Maternal Diet May Affect Stress Responses in Children and Animal Protein, Pregnancy, and Childhood Obesity.

Protein is such a misunderstood nutrient. For more information, check out:

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: