Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Breast Cancer Health Center

Font Size

Phytoestrogens May Not Prevent Breast Cancer

Study Shows Reduction in Breast Cancer Risk Not Seen Even if Started at Early Age
WebMD Health News

Feb. 4, 2003 -- You may have heard that diets rich in soy that contain phytoestrogen help protect against breast cancer. Now, new research from The Netherlands indicates that diets containing phytoestrogens typically found in Western diets do not show a protective effect.

Researchers studied the association between the consumption of plant-based compounds that have estrogen-like activity, known as phytoestrogens, and breast cancer risk in a study involving more than 15,000 middle-aged and elderly Dutch women.

The main sources of phytoestrogens in the women's diets -- as is the case for most women in the U.S. -- were not soy and flaxseed, but grains, fruit, nuts, and seeds. And like most people eating primarily Western diets, the overall consumption of phytoestrogens was low.

Breast cancer risk among women eating diets containing the highest amounts of these phytoestrogens was similar to those eating lower amounts. The findings are published in the latest issue of the American Journal of Clinical Nutrition.

Studies Contradict

Most previous studies examining the role of dietary phytoestrogens in breast cancer have focused on soy. Soy researcher Marc Cline, PhD, tells WebMD that the evidence to date remains more than a little contradictory.

Population-based studies seem to overwhelmingly support a protective role for soy phytoestrogens. American women have a breast cancer risk that is as much as six times higher than women who live in Asian countries, where diets rich in soy phytoestrogens are commonly eaten. When Asian women immigrate to the U.S. and adopt more Western diets, they develop a higher risk of breast cancers.

"These are the studies that got people excited about soy," Cline tells WebMD. "But there are a lot of other factors, in addition to diet, that can explain this difference, Asian women typically consume fewer calories overall, they begin to menstruate later in life, they exercise more, eat more vegetables and are thinner than women living in the West."

Studies directly measuring the impact of soy consumption on breast cancer risk show a "weak protective effect", with women who eat soy throughout life and starting at an early age appearing to derive the most benefit, Cline says.

Today on WebMD

Breast Cancer Overview
From self-exams and biopsies to reconstruction, we’ve got you covered.
Dealing with breast cancer
Get answers to your questions.
woman having mammogram
Experts don’t agree on all fronts, but you can be your own advocate.
woman undergoing breast cancer test
Many women worry. But the truth? Most abnormalities aren’t breast cancer.
Breast Cancer Treatments Improving
Resolved To Quit Smoking
Woman getting mammogram
Screening Tests for Women
ovarian cancer overview slideshow
serious woman
what is your cancer risk
10 Ways to Revitalize Slideshow