News Health & Medicine Look Ma, Too Much Soy: Hormone in infant food reduces immunity in mice By Ben Harder May 22, 2002 at 9:23 am - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Share on Facebook (Opens in new window) Facebook Share on Reddit (Opens in new window) Reddit Share on X (Opens in new window) X Print (Opens in new window) Print The health benefits of soybeans are legion, but too much of the food may have a downside. HOLD THE HORMONES. Soybeans contain estrogens that, in excessive quantities, may produce immune problems. United SoyBean Board A new study finds that large doses of the estrogenlike hormones that occur naturally in soybeans weaken the immune systems of mice.