Alternative medicine, including the use of herbal remedies, has become quite popular among Americans. Estimates indicate a third of the population now consumes some form of herbal supplement. While the vast majority of these supplements are basically safe, as with anything, both good and bad can result from their consumption. Always keep your physician or pharmacist informed about any herbal products you may be taking.
Hot flashes? Well, soy may be just the thing for you. Or maybe not. Soy supplements have hit the news as being effective in reducing hot flashes and other undesirable symptoms of menopause. It has also been studied in reducing cholesterol levels, cancer prevention, and treating osteoporosis. So what's the truth?
Soybeans and other foods containing soy, such as tofu and soy milk, are commonly found in Asia and are a staple of the Asian diet. Soy is rich in protein and isoflavones (genistein and daidzein), as well as saponins and phytosterols. Soy is low in fat and contains no cholesterol. Soy has also been introduced as a meat substitute in hot dogs, tacos, and breakfast links.
The isoflavones genistein and daidzein have antioxidant properties and are considered phytoestrogenic (mimic the effects of estrogens, the female hormone). This may be the reason that some women who eat tofu get relief from hot flashes during menopause. There are many products on the market touting the benefits of isoflavones and soy for the symptoms of menopause, but clinical studies give mixed results with the label of "possibly effective." The recommended dose is 20-60 grams of soy protein (34-76 milligrams of isoflavones) daily. Check with your physician before starting on soy to ease hot flashes.
Soy has proven effective, however, in lowering the levels of low-density lipoprotein, or bad cholesterol, in the body, especially when used in conjunction with a diet low in fat and cholesterol. The Food and Drug Administration recommends 25 grams of soy protein a day to be effective in lowering cholesterol levels roughly 10 percent.
Soy's use to build strong bones is another "possibly effective" benefit. Soybeans are rich in calcium, but soy milk in itself has only 10 milligrams of calcium per serving. Calcium-fortified soy milk is a better choice.
Soy milk should not be used as infant formula. While it is sometimes promoted for children with milk allergies, it should not be given to an infant or child without first checking with a physician. Children allergic to milk may very well be allergic to soy, also.
Speaking of allergies, one of the most common reactions to soy is gastrointestinal upset, such as nausea and constipation. Soy can also cause rashes and itching. Patients with certain medical conditions should be cautious when eating products containing soy. These disease states include breast cancer (estrogenic properties may increase the risk of developing breast cancer in patients with a family history), cystic fibrosis, hypothyroidism, or an allergy to milk.
The benefits of soy are often used when comparing men and women in Asia to men and women in the U.S. Asians have lower cancer rates, lower cholesterol levels, and have fewer hot flashes (well, at least Asian women) and, reportedly, eat more soy. Diet and lifestyle may have more influence on the rates of cancer or the number of hot flashes each group experiences than does the amount of soy that each consumes.
In many cases the use of herbal supplements or nutritional aids and their benefit is questionable. Your pharmacist recommends prudent intake of soy and isoflavone supplements. Above all, talk to your pharmacist or health-care provider prior to taking any "natural" product. Ask questions.
(Editor's note: Almquist is chief of the Department of Pharmacy at Madigan Army Medical Center)
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