Soy and menopause.

Many women choose to use hormone replacement therapy (HRT) to relieve some of the symptoms of menopause like hot flushes (also called hot flashes). Recent reports have led many women to question the safety of HRT and to look for other ways to reduce hot flushes. Soy products have been proposed as an alternative. Mark Messina, PhD, and Claude Hughes, MD, PhD, reviewed 13 studies that tested the effects of soyfoods or soy isoflavones on hot flushes. They found that soyfoods or isoflavone supplements were most effective in women with frequent hot flushes. For example, they estimate that women with 10 hot flushes per day who begin using soyfoods or isoflavones, will, on average, have about 4.5 fewer hot flushes daily.

Women experience a marked increase in the rate of bone loss in the years immediately after menopause. Soy protein appears to help to maintain bones, especially in women who are not using hormone replacement therapy (Arjmandi). Soyfoods and isoflavones may also reduce the risk of heart disease in postmenopausal women. Messina and Hughes recommend that women with frequent hot flushes try using soyfoods or isoflavone supplements that provide around 50 milligrams of isoflavones per day. They recommend an upper limit of 100 milligrams of isoflavones per day.

Messina M, Hughes C. 2003. Efficacy of soyfoods and soybean isoflavone supplements for alleviating menopausal symptoms is positively related to initial hot flush frequency. J Medicinal Food 6:1-11.

Arjmandi BH, Khalil DA, Smith BJ, et al. 2003. Soy protein has a greater effect on bone in postmenopausal women not on hormone replacement therapy, as evidenced by reducing bone resorption and urinary calcium excretion. J Clin Endocrinol Metab 88:1048-54.