Soy: The Unsuspected Cause of Thyroid Problems?

Dear Weston A Price Foundation:

A few days ago I came across Stephen Byrnes' article on "The Myths of Vegetarianism," and was astounded to learn about the adverse effects of the goitrogens and phytoestrogens in soy. References in that article led me to your website where, this morning, I read the articles about the negative effects of soy. . . and everything fell into place.

I just threw out the so-called healthful soy protein powder and tofu and toasted soy nuts in my refrigerator, because I now realize my eating soy products is probably related to the fact that a recent blood test indicated I'm hypothyroid, with a TSH level of 7.

For many years I've tried to figure out the cause of frequent headaches, fluid retention, weight gain, fatigue, mood swings and hypo-glycemic reactions to carbohydrates. While I have reduced the frequency and severity of these systems by eschewing most of the dietary recommendations of the food establishment (I eat plenty of meat, lots of vegetables, fruit, nuts, butter, olive oil, take supplements including fish and flaxseed oils, and avoid grains and other highly concentrated carbohydrates), I've been struggling for the last two years with recalcitrant though mild weight gain (I'm about 10 pounds over my normal weight) and chronic tiredness.

When I had my blood tested last month at a local health fair and found out I was hypothyroid, I started eating dulse seaweed and taking l-tyrosine to support my thyroid gland. I've had thyroid problems in the past, including two cysts, one in the mid-1980s which was drained easily by needle, and another recent one that spontaneously subsided after I massaged it gently for a few days.

My husband and I were vegetarians in the early 1980s, but I didn't feel all that well on that diet so we reverted to eating meat. I thought my failure to do well on the vegetarian diet was because I didn't know how to combine foods properly to obtain complete proteins.

Like many people, I was taken in by the hype about the health benefits of soy, so have used soy powders and tofu frequently though intermittently over the last 20 years or so. Fortunately I never gave up meat as I discovered the Atkins diet in the late 1980s and found his high protein/low carbohydrate regimen helped me considerably. Interestingly, I also read Dr. Price's book in the mid-1980s, and the information I gleaned from his book and the Atkins diet information confirmed my personal observations that I do better on a meat-based diet. So I never stopped eating meat, but while avoiding grains and most carbohydrates helped reduce many of my symptoms, it didn't solve all the problems, and I never was able to figure out why some of my symptoms continued.

I NEVER suspected soy and its goitrogens and phytoestrogens. In fact, I'd been eating MORE soy products recently, thinking that might help! So, now I'll see whether my thyroid recuperates and my energy returns on my already good, sensible, this-is-what-nature-intended diet. . . sans soy! Thank you for making this information available!

L. B.
Lakewood, CO

Phytoestrogens in Soy Depress Immune Function

An article published in the Proceedings of the National Academy of Science (May 28, 2002;99(11):7616-7621) has raised new concerns about soy. Researchers injected mice with the soy isoflavones genistein and daidzein and then looked at the thymus gland.

They found that the injections produced dose-responsive decreases in thymic weight of up to 80 percent. In other words, the more isoflavones given, the greater decrease in the weight of the thymus gland. The genistein-injected mice showed a large decrease in the number of immune cells and changes in the thymus, where immune cells mature. Genistein decreased thymocyte numbers up to 86 percent and doubled apoptosis (cell death), indicating that the mechanism of the genistein effect on loss of thymocytes is caused in part by increased apoptosis. In addition, genistein produced suppression of humoral immunity. Genistein injected at 8 mg/kg per day produced serum genistein levels comparable to those reported in soy-fed human infants, and this dose caused significant thymic and immune changes in mice.

Said the researchers: "Critically, dietary genistein at concentrations that produced serum genistein levels substantially less than those in soy-fed infants produced marked thymic atrophy. These results raise the possibility that serum genistein concentrations found in soy-fed infants may be capable of producing thymic and immune abnormalities, as suggested by previous reports of immune impairments in soy-fed human infants."

These results explain the frequent infections, high fevers and autoimmune problems (including diabetes) that often occur in soy-fed children.

Unlike earlier reports on the negative effects of soy, this study was actually reported in a major newspaper. "A Closer Look at Soy and Babies" appeared in the Science section of the New York Times, May 21, 2002. The article quotes Dr. Paul S. Cook, head of the study, as stating that "parents whose babies did not need to drink soy formula for health reasons, like allergies, should consider using milk-based formula instead, if they do not breast feed." Mead Johnson Nutritionals, maker of soy formula, naturally defended the use of soy formula. But this article represents the first hole in the media dike and yet another warning to parents to avoid soy formula for their babies.

This page was posted on 12/05/03