Breast Cancer Survival and Soy

In my Care2 posts last week, The Best Detox and Breast Cancer Stem Cells vs. Broccoli, I documented ways to boost our liver’s ability to clear carcinogens, make our DNA more resistant to any damaging agents that make it past our first line of defense, and then ramp up immune surveillance of any budding tumors—all in hopes of preventing cancer. But what about for those who already have it?

Though small consolation, one consequence of the fact that breast cancer is now the #1 cancer killer of young women is that breast cancer survival is a very active area of research. For example, a major study was recently published that followed 4,000 women with breast cancer for 7 years. Not all of them made it to the end. The researchers tried to figure out if there was anything about the diets of the non-survivors that may have played a role in their deaths. Two dietary components in particular were associated with an early death: saturated fat and trans fat.

Breast cancer survivors may decrease their risk of dying by 41% simply by avoiding saturated fat, found primarily in the American diet in cheese, chicken, and junk food (see my 3-minute video Breast Cancer Survival, Butterfat, and Chicken). And breast cancer survivors may improve their survival 78% by avoiding trans fat, found primarily in in junk food and animal products (see my 1-minute video Breast Cancer Survival and Trans Fat). Ideally everyone should try to minimize the intake of both, as explained in Trans Fat, Saturated Fat and Cholesterol: Tolerable Upper Intake of Zero.

On the other hand, the two foods expected to improve breast cancer survival are flax seeds and soy products. Breast cancer is initially so slow-growing that women may have tumors for years or even decades before they’re diagnosed (see my 1-minute video Cancer Prevention and Treatment May Be the Same Thing). So one might expect that the same dietary factors that helped grow the tumor in the first place would keep goading it on after diagnosis. This may not always be the case, though. Alcohol, for example, is strongly associated with breast cancer risk, but the data has been mixed as to whether once you already have a full-blown tumor, it makes a difference if you continue to drink or not. Still, in general, the diet that helps prevent breast cancer is the same diet that’s going to help prolong survival. And that certainly seems to be the case for the phytonutrients found in flax and soy.

Flax seeds are the most concentrated source of lignans, a class of cancer-fighting compounds that may cut breast cancer mortality risk in half (see my 3-minute video Breast Cancer Survival and Lignan Intake). Interestingly, there are no lignans actually found in the seeds, just precursors that the good bacteria in our gut turn into lignans. This may explain why women who have frequent urinary tract infections have higher breast cancer rates—the courses of antibiotics wipe out the gut flora critical to the production of these anti-cancer compounds (see my 2-minute Flax and Fecal Flora).

Soy foods appear to help prevent breast cancer and prolong survival more directly, though—the subject of today’s NutritionFacts.org video pick shown above.

In health,
Michael Greger, M.D.

image credit: imgdive / Flickr and MesserWoland / Wikimedia Commons

Disclaimer: The views expressed above are solely those of the author and may not reflect those of
Care2, Inc., its employees or advertisers.

Vikki H.

2:57PM PST on Jan 25, 2013

My type of breast cancer is estrogen positive so I was encouraged to eat less soy. Itake an estrogen blocker everyday. Now I'm confused

January 25
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Dale O.

8:22AM PDT on Jul 31, 2012

It would be nice if people expressing differing viewpoints could just discuss things pleasantly without bashing each other with two by fours.

Think that I will avoid soy for the most part because of GMO problems and stick to quinoa and yes meat in small portions, salad, fruit and veggies.

July 31
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11:13AM PDT on May 7, 2012

Thanks for posting.

May 7
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Lynda H.

7:44AM PDT on May 6, 2012

Jelka V, I think I can answer your question. Care2 pushes vegetarianism/animal rights (not welfare), and it is difficult to get enough protein on a vegetarian diet - especially a vegan one. Soy is very high in protein, and can be processed to imitate meat or dairy. Even if bona fide, real scientific studies prove how bad non-fermented soy products are for you, bogus, biased studies can be easily manufactured to refute them.

They’re still pushing the long debunked saturated fat and cholesterol warnings, for the same reason. http://www.cholesterol-and-health.com/Does-Cholesterol-Cause-Heart-Disease-Myth.html#17

This article was presented by Dr Michael Gregor, one of the vegan directors of the animal rights group HSUS. http://www.ncraoa.com/AR_AW_WhatYouShouldKnow.html

May 6
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7:09AM PDT on May 6, 2012

Joe R.

4:42AM PDT on May 6, 2012

A bit confused here. Lots of conflicting opinions.

Bob P.

3:41AM PDT on May 6, 2012

thanks

Alice D.

4:24PM PDT on May 4, 2012

There is no such thing as organic soy! Please educate yourselves and read "The Whole Soy Story" by Kaayla T. Daniel or, "The Vegetarian Myth" by Lierre Keith or, "Primal Body-Primal Mind" by Nora T. Gedgaudas. It is not the health food it has been promoted to be and please! don't give soy milk to small children.

May 4
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Jelka V.

1:08PM PDT on Apr 30, 2012

Why, WHY does this website keep promoting non-fermented soy as a healthy food, when it's been know known for years now that it can wreak serious havoc with your hormones?!

Fermented soy is great. Non-fermented soy... I wouldn't touch it with a barge pole.

Seriously, people, do you have any idea of how irresponsible it is to mindlessly promote these decade-old myth?