The Truth about Soy

Where to start? We’ve all heard that soy is a health food – a great source of protein, a substitute for meat and milk. It is the backbone of a vegetarian diet and has launched a whole new wave of “health foods”. Unfortunately most of these new creations are not healthy and in many cases one could argue if they are even food! The truth is that soy consumption is hazardous to your health. The soy industry spends millions of dollars creating new products and marketing them. Studies are cited to “support” the health claims. Of course the more the study is investigated, the more the inconsistencies and inaccuracies become apparent. For an excellent expose on the soy industry I highly recommend the book The Whole Soy Story: The Dark Side of America’s Favorite Health Food by Kaayla Daniel, PhD. Or, on the web visit The Weston A. Price Foundation at www.westonaprice.org. For this article I’m going to focus on three key reasons why soy is not good for you. For a more complete list and more details I refer you to the book and the web site.

1. Soy is bad for your thyroid. Soy contains goitrogens – substances that suppress thyroid function by inhibiting your body’s ability to make thyroid hormones and may cause hypothyroidism (low thyroid function). The thyroid is responsible for metabolism. Impaired metabolism can result in weight gain, fatigue and diminished sex drive. Soy consumption has also been linked to thyroid cancer in adults and autoimmune thyroid disease in infants.

2. Soy is hard to digest. Soy contains one of the highest levels of phytates of any grain or legume. Phytic acid reduces the assimilation of key minerals that your body needs including calcium, magnesium, copper, iron and zinc. Unlike other grains and legumes the phytic acid in soy is not neutralized by soaking, sprouting, or cooking. The only form in which the phytates are broken down is fermented. Fermented soy products include tempeh, miso, and natto. These are the only soy products I’d recommend eating.

Soy also contains trypsin and protease (enzyme) inhibitors which interfere with protein digestion. So, go figure, we are told to eat soy as a protein, yet its very essence does not allow us to digest it!

High phytate diets have caused growth problems in children and test animals fed soy exhibited stunted growth. Perhaps you might want to reconsider using soy baby formula. The Israeli Health Ministry issued an advisory for young children and adults to use soy sparingly and for infants to avoid it completely!

3. Soy is disruptive to endocrine gland function for both men and women. In women soy phytoestrogens have been linked to infertility and breast cancer. What about the old story that Japanese women eat lots of soy in Japan and do not get breast cancer until they come to the United States? Another great story. They do not eat lots of soy. The soy they do eat is mostly fermented. And, they eat lots of other healthy foods like more wild fish and sea vegetables.
For men the story is not much better. Remember the Seinfeld episode about the “Mansiere” or the “Bro” – Cramer’s invention for male breasts? Well, that’s what can happen from too much soy. There is a great story in the recent issue of Men’s Health about a man who was drinking three quarts of soy milk a day and developed breasts. Soy also has been linked with sperm count reductions. A study found men consuming soy on a daily basis have 32% less sperm per milliliter of ejaculate.

Unfortunately there is more, but I’m out of space in this column. I haven’t even mentioned what happens when soy is processed to make veggie burgers, veggie chili, soy cheese, etc and what they add to it to make it palatable.

I sincerely hope you have found this article informative. Unfortunately the nutrition industry is full of hype and misinformation. It takes time and research to discover the truths. When something is repeated and repeated we start to believe it is true, just because everyone is saying it. As I like to tell my clients – I was a vegetarian before I studied nutrition!


Bernard Rosen, PhD is a Nutrition Consultant and Educator. He works with individuals, groups, and at corporations to create individualized nutrition and wellness programs. His office is in Thiensville, WI. To learn more or to schedule an appointment, e-mail at bernie@brwellness.com, call (262) 389-9907 or go to www.brwellness.com.