Monday, June 22, 2009

Soy's estrogenic effects on males?

Dear Monique, I have been a vegetarian for 5 years now and I have used soy almost every day in some form or another. I was reading last week about the estrogen "effect" of soy. Of course, I have heard menopausal women using soy can really help them. But now, the question of what it is doing to boys, men, or even other younger women and girls. Not to mention what affect it may have on children/babies who have had soy formula.

I was under the notion that the steroids that are given to animals are the reason why children are maturing at a younger age, etc... Since I don't eat meat (neither has my son, 3 1/2 yrs. old, who has been breastfed and never fed formula), I didn't think this was a problem for us. What have others heard about this? Is there any truth to boys and men, even girls and younger women eating soy (a lot, I'm not talking about now and then) and estrogen "problems?"

This article I read also mentioned that even "100 gm of any soy product has the estrogenic content of a contraceptive pill." Right now we have been trying to get pregnant for about 2 years now. If this article has any truth to it, I will do less soy. I will not stop eating it, but I will seriously consider using it much less. Just trying to figure this out. I would love to hear what others know or have heard about this question.

Answer: The conflicting reports about soy's estrogenic effects have caused concern and confusion to many parents and parents-to-be. Ever since findings on isoflavones ability to "mimic" estrogen has surfaced, all kinds of rumors about soy's negative effects have emerged. Some of these misinformed statements include: it will make male infants more effeminate; it can lower the libido; it causes males to get larger breasts.

However, I have found that most of these rumors are unsubstantiated, and that there have been no reports or studies published from credible sources that indicate that they are in fact true. Soy foods have been used in Asian countries for well over two thousand years, without causing fertility problems or interfering with the hormones of their male population.

Additionally, for roughly 60 years soy formula has been used in the U.S. without any statistical data that would support any need for concern. In fact, The American Academy of Pediatrics supports the use of soy formula for children who cannot or will not consume breast milk or cow's milk-based formula. They found no significant differences in sexual development or preferences in adult males and females who consumed soy-based formula as infants compared to those who had milk-based formulas. I truly believe that they wouldn't endorse soy formula use if there were nutritional or hormonal concerns. There is a large body of research supporting the safety and use of soy-based infant formulas.

To read more about soy formula safety, read my Q&A...

"Is infant soy formula better than milk-based formula?"

It is also interesting that most body building formulas have soy protein isolate as their primary ingredient (that is 70% or more by weight). These products are largely consumed by men and have not resulted in the development of feminine features.

Since I have not read the article you are referring to, I cannot comment on its accuracy. However, I have found a few studies which have suggested that eating large quantities of RAW or UNDERCOOKED soybeans may affect fertility and possibly developing fetuses. Until scientists know more, pregnant women and those having difficulty conceiving may want to reduce their exposure to estrogen rich foods, like soy, and not take any isoflavone supplements. They should only consume, in moderation, fully cooked soy foods like tofu, or fermented soy products like tempeh and miso.

Generally, Asian women have not shown detrimental effects from eating soy foods before, during or after pregnancy. Therefore, we can surmise that a well balanced plant-based diet with a moderate amount of soy would be safe for pregnant and nursing American women. However, since you are having problems conceiving, I suggest that you discuss soy consumption with your doctor to find out how much is okay for you to use during this time.

For more information about soy,

Read my Q&A's

Soy and reproductive health?

Soy for men versus women?

and visit the Virtues of Soy website.

Also read "Vegetarian Diets for Children: Right from the Start" at

Recommended Books...

Plant Based Nutrition and Health
by Stephen Walsh

The New Becoming Vegetarian: The Essential Guide To A Healthy Vegetarian Diet
by Vesanto Melina & Brenda Davis

The Food Revolution: How Your Diet Can Help Save Your Life and Our World
by John Robbins

Virtues of Soy: A Practical Health Guide and Cookbook
by Monique N. Gilbert

Dr. Spock's Baby and Child Care (8th edition)
by Benjamin Spock

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Monique N. Gilbert, BSc. has offered guidance in health, nutrition, fitness and stress management since 1989. Through her writings, Monique motivates and teaches how to improve your well-being, vitality and longevity with balanced nutrition, physical activity and healthy stress-free living.

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