Soy
Asian cultures have known about soy for years, but soy is a relatively new food to the American diet. In recent years, soy has emerged as a nutritional powerhouse, thanks to studies that have linked it to fighting disease. Isoflavones, substances found in soy, are said to help combat breast cancer, tame the hot flashes of menopause, limit the bone loss that occurs in postmenopausal women, and reduce your risk of heart disease by lowering cholesterol. In essence, soy acts as a phytoestrogen, or plant estrogen.
But a study in early 2006 in the journal
In addition, soy had little effect on hot flashes and bone loss in postmenopausal women. They also found no evidence that soy could treat or prevent certain cancers, including breast cancer. But the researchers did not discount the benefits of certain soy products, which are high in protein, fiber, vitamins, and minerals.
Where Is Soy?
Soy is a bean found in foods as varied as tofu, tempeh, soy milk, soy sauce, and miso, a soybean paste. The excitement over soy has unleashed a tidal wave of new soy products, including soy burgers, soy shakes, and soy cereals. People also use tofu to make chili, lasagna, and desserts.
Troubles with Soy
In people who have hypothyroidism, too much soy can aggravate a thyroid problem. The isoflavones found in soy can increase TSH levels, causing an increase in thyroid hormone requirements and the potential for goiter. In women, excess soy can cause menstrual irregularities that may lead to infertility.
Soy can also inhibit absorption of thyroid medications. So if you like to eat soy, make sure you don't eat it around the same time you take your thyroid medication. Instead, you should wait at least four hours after taking your thyroid medication before eating anything that contains soy.
