Q. I’ve heard that soy is generally good for women’s health, but not in all cases. Can you explain?
A. Soy products and their effects on health have been the subject of much debate. Studies have shown conflicting results, but as more research is done the soy picture is becoming increasingly clear.
Many women have increased their consumption of soy because of its health benefits. Researchers have found that soy helps your heart by lowering triglycerides and cholesterol, including the “unfriendly” LDL cholesterol. Soy may also support your bones by inhibiting bone resorption (calcium loss from your bones). In addition, soy products can help some women with menopausal hot flashes and night sweats.
Much of the research on how soy affects a woman’s breast tissue has focused on the estrogenic properties of the soy-derived isoflavones genistein and daidzein. Compared to the estrogen a woman’s body naturally produces, these isoflavones have weak estrogen-like effects.
According to a recent article in Advanced Practice in Acute Critical Care, some studies show that women in Asia who consume a high-soy diet have a lower risk of breast cancer than Western women. But when Asian women move to the West and adopt a Western diet, their lower risk is diminished.
Epidemiological studies have suggested that high concentrations of soy isoflavones in the diet are related to reduced breast cancer risk.
The age of exposure to isoflavones may be important: studies have associated lowered risk of adult breast cancer with adolescent consumption of isoflavone-rich soy. Yet animal and test tube studies have shown that soy isoflavones could increase the proliferation of breast cancer cells.
A study published in May in the journal Carcinogenesis suggests that a lot depends on how you ingest soy. The study found that breast tumor growth was stimulated when the isolated soy isoflavone genistein was consumed, but not when whole soy food products were ingested. Most women in Asia eat whole soy foods, because soy products in Asian countries are minimally processed. In contrast, many women in the United States frequently consume processed soy products containing large amounts of isoflavones in the form of genistein capsules or powders. Thus, U.S. women often miss many biologically active compounds found in whole soy foods.
The good news is that products made with whole soy foods are widely available. They include tofu, soy flour, miso soup, soybeans (edamame), soy protein powder and soymilk.
Article was originally printed in the Honolulu Advertiser, honoluluadvertiser.com