soy and thyroid

[Quiet Heather]

I was told that my TSH level was borderline and was wondering if I should eat less soy because of this. Can soy cause thyroid problems? Thanks!

[JeffN]

I was told that my TSH level was borderline and was wondering if I should eat less soy because of this. !

Hi Heather

I think you should eat less soy, no matter what.

If you have read my posts/threads on soy, I recommend that "if" you include it in your diet, that it should be no more than a condiment and only in the forms that are the least processed. At that level, there is really little if any risk at all from these "concerns" that have been raised. Remember, that in soy consuming countries, they only average about 1-2 oz a day.

Can soy cause thyroid problems? Thanks!

There is some evidence on both sides of the argument though most of the negative is in infants fed large amounts of soy in a pure soy formula.

Dr McDougall addresses it in one of his newsletters

http://www.drmcdougall.com/misc/2005nl/ ... 0pusoy.htm

Argument 5: Thyroid

Detrimental: Goiter and hypothyroidism have been reported in infants receiving soy formula. Autoimmune diseases of the thyroid and thyroid cancer may also be caused by exposure to soy.11-12

Beneficial: The addition of adequate iodine to the diet reverses any goiter-causing effects of soy. Population studies suggest soy protects against thyroid cancer.13

11) Divi R. Anti-thyroid isoflavones from soybean: isolation, characterization, and mechanisms of action. Biochem Pharmacol. 1997 Nov 15;54(10):1087-96.

12) Doerge DR, Sheehan DM. Goitrogenic and estrogenic activity of soy isoflavones. Environ Health Perspect. 2002 Jun;110 Suppl 3:349-53.

13) Horn-Ross PL, Hoggatt KJ, Lee MM. Phytoestrogens and thyroid cancer risk: the San Francisco Bay Area thyroid cancer study. Cancer Epidemiol Biomarkers Prev. 2002 Jan;11(1):43-9.

So, I don't think there is one clear answer, though, this is why, if we include soy, it should be a minimal amount and in addition, if we are concerned, there is no harm in eliminating it.

In Health
Jeff

[Quiet Heather]

Thanks. I already consume a fairly small amount of soy - a little soy milk in my coffee (when I drink it which isn't daily) and in recipes and occasionally some tempeh. I'm sure it's not more than 1-2 oz a day, on average. I appreciate your input.