Soy Estrogen Myth: Is it Good or Bad to Consume Soy?

By Jessica Wise

Disclaimer: This post is not intended to be taken or received as nutritional advice nor is the author able to offer nutritional advice. Each patient who is interested in statements made herein should consult with a qualified medical professional to learn more.

Soy foods are naturally cholesterol-free, low in saturated fat, and high in fiber. In many ways, soy foods are an excellent source of protein and a great alternative to red or processed meat; however, there is conflicting information regarding the potential effect of soy consumption on breast cancer development. While some experts emphasize the beneficial effects of soy foods, others believe soy may increase a person’s risk of developing breast cancer. Let us begin by understanding why this might be.

Phytoestrogens and breast cancer

Natural soy foods contain phytoestrogens, plant-based estrogen compounds. Since estrogen is linked to certain types of hormonal breast cancer, many individuals fear that soy can increase their risk for breast cancer development. There have been several research studies conducted to assess the association between soy consumption and breast cancer development; animal studies have primarily established a positive correlation between soy consumption and breast cancer, but human population studies have not produced this same result.

Soy foods are a staple in traditional Asian diets, making the intake of soy foods across the lifespan of Asian men and women much higher than that of American men and women. Recent studies have tried to understand the potential effect of soy consumption on breast cancer development in Asian women, and the evidence does not indicate a detrimental effect. In fact, the evidence points to a beneficial effect: Consumption of soy foods may lead to a decreased risk of breast cancer among Asian and Asian American women.

In the US, soy consumption often comes from soy additives in foods or processed soy foods. It is known that processed foods can increase a person’s risk for cancer, so perhaps we should focus on eating whole soy foods like edamame and tofu. For those of you who are concerned about eating soy foods and their risk of breast cancer development, then there is no need to add soy to your diet. Like any food, consuming soy in moderation is important.

Here is a list of phytoestrogen foods that are healthy in the unprocessed state:

· Tofu

· Tempeh

· Edamame

· Linseed (flax)

· Sesame seeds

· Barley

· Lentils

· Alfalfa

· Mung beans

· Apples

· Carrots

References:

Korde, L. A., Wu, A. H., Fears, T., Nomura, A. M. Y., West, D. W., Kolonel, L. N., Pike, M. C., Hoover, R. N., & Ziegler, R. G. (2006). Childhood soy intake and breast cancer risk in Asian-American women. Cancer Epidemiology and Prevention Biomarkers, 15(12 Supplement), B163–B163.

Phytoestrogens: Benefits, risks, and food list. (n.d.). Retrieved June 11, 2020, from https://www.medicalnewstoday.com/articles/320630

Ziaei, S., & Halaby, R. (2017). Dietary Isoflavones and Breast Cancer Risk. Medicines, 4(2).