During menopause, the amount of estrogen produced in a woman's body decreases and, as a result, many women suffer symptoms such as fatigue, irritability, hot flashes and night sweats. These symptoms can last for years. Since soybeans contain estrogen-like compounds known as isoflavones, soy foods and soy supplements may provide some relief. And because isoflavones provide this relief without any known side effects, soy products are often recommended as an alternative to hormone replacement therapy in post-menopausal women.
Background
When scientists observed that Asian women suffer fewer of the symptoms typical of menopause than Western women, they began to look for an explanation. When they looked at diet, it was noted that Asians consume notably more soy foods than Westerners. When researchers looked at the individual properties of soy foods, they found that soybeans contain phytoestrogens, or plant-based estrogens, known as isoflavones, that are similar in chemical structure to estrogen produced by the human body. A theory evolved that soy foods might have a weak but notable estrogen-like effect in the body that diminishes the symptoms of menopause in some women.
Expert Insight
A series of clinical studies published in the journal "Menopause" found that one particular isoflavone in soybeans, known as genistein, significantly reduced the incidence and severity of hot flashes. The results were similar whether women consumed soy protein or supplements.
When Dr. Mark Messina, a soy expert and nutrition professor at Loma Linda University, evaluated 19 clinical trials involving the use of soyfoods and isoflavones in over 1,700 women, similar results led him to publish his opinion in the "Journal of Medicinal Food" that women can consider eating soy foods or taking isoflavone supplements to relieve hot flashes.
Additional Benefits
The health issues that can arise for women with the loss of estrogen in menopause include decreased bone density that can lead to osteoporosis, an increased risk of fractures, and an increased risk of heart disease and stroke. Soy foods may help lower these risks. A study of post-menopausal women published in the "Annals of Internal Medicine" indicated that genistein helps increase bone density without side effects.
In addition, research led to the health claim--approved by the U.S. Food and Drug Administration--in 1999 that a daily dose of 25 g of soy protein can help reduce cholesterol in the blood if taken in the context of an overall low-fat diet. This claim has since been called into question, but experts like Dr. Messina say that even if the cholesterol-lowering effects of soy are modest, there is still evidence that soy plays a role in lowering blood pressure and other aspects of heart health.
Soy Foods
Soy protein and isoflavones are found in edamame (fresh green soybeans), tofu, soy milk, soy yogurt, soy nuts, tempeh, miso and other foods made from soybeans.
Dose
For optimal benefit, Dr. Messina recommends consuming at least two or three servings of soy foods daily.
If you think isoflavone supplements might help you, discuss the possibility and dosage with your doctor.
