To Your Health
Are soy foods really good for us or not?
A: Soy foods are popular, not just with vegetarians but with a lot of health-conscious people. Soy is generally low in sodium and rich in protein, fiber, and trace minerals, as well as isoflavones. Isoflavones are also called phytoestrogens because they are derived from plants (hence the phyto-) and have estrogen-like activity. Isoflavones are credited with improving menopausal symptoms such as hot flashes, vaginal dryness, cognitive disorders, and emotional disturbances. As a bonus, they may also work to reduce the risk of heart disease and osteoporosis.
Isoflavones are considerably weaker than the estrogen hormone the body produces, and may have both estrogenic and anti-estrogenic effects. Isoflavones may block estrogen receptor sites, producing a weak estrogen effect but blocking natural estrogen's stronger estrogen effect.
Most soy products have two-to-four milligrams of isoflavones per gram of protein, or about 20-40 mg per serving. Substituting two servings of soy protein per day for animal protein can be beneficial in lowering total cholesterol and LDL ("bad") cholesterol and raising HDL ("good") cholesterol.
There is some concern, however, in using isoflavones as a supplement, perhaps because the supplemental amounts are sometimes in the hundreds of milligrams per day. No one yet knows the most beneficial amount of soy isoflavones, much less of the synthetic isoflavones. There is consensus that one-to-two servings of soy products per day should be beneficial and not harmful, but there is much to learn about supplemental isoflavones and synthetic isoflavones.
Q: My mother, at age 58, has just become the third woman in her immediate family to be diagnosed with breast cancer. Since menopause she had been taking hormones but has now stopped, and is suffering greatly with hot flashes. I hate to think that this is in store for me. Is it inevitable?
A: In the past few months, hormone replacement therapy (HRT) for postmenopausal women has made headlines twice! In a study, published in the Journal of the American Medical Association in March, it was found that the estrogens used in HRT (Premarin is an example) increased breast cancer risk 1% per year of use. And when combined with synthetic progesterone (Provera is a common one), the cancer risk was increased 8% per year. In April, the early results of another study were released suggesting that the estrogens used in HRT, which have long been known to slightly increase the incidence of blood clots, and therefore strokes, may also increase the risk of heart attacks. In addition, synthetic progesterone had previously been shown to have increased the risk of heart disease.
Given this information, it seems wise for women and their doctors to compare the safety and efficacy of traditional HRT with other hormone approaches now available.
One new choice is natural progesterone, identical to that made in the human body, used alone or in combination with some form of estrogen. A number of studies indicate that natural progesterone protects against cancer and promotes bone growth. When estrogen is also needed, natural estrogen such as estriol, which does not initiate or promote cancer, provides a safer choice.
As science works to improve the safety and quality of HRT, let's hope for clear heads and open minds to evaluate past protocols and new alternatives. And may we as consumers continue to increase our participation in gathering information and making decisions involving or own health.
James Heffley, Ph.D., is a certified clinical nutritionist. The information he provides is for educational use only. If you believe you have a medical problem, see your physician.