And, speaking of mistruths in advertising, soy supplements are another product whose health claims have not panned out.
Soy protein contains chemicals called phytoestrogens, known to weakly bind to estrogen receptors. Thus, they have been promoted as an alternative therapy for menopausal women who fear the risks associated with standard estrogen replacement therapy. Yet, so far, very little has been found to support this theory. In fact, a study just published in the Archives of Internal Medicine has found that soy supplements were not at all beneficial to menopausal women.
Researchers from the University of Miami conducted a randomized controlled trial over a five-year period: two groups of about 120 menopausal women each were given either a daily 200 mg dose of soy isoflavone, or a placebo.
Over the course of the two-year follow-up, there was no significant difference in the bone mineral density of women who took the supplement and those taking the placebo. Ironically, a significant proportion of the women who took the soy supplement experienced hot flashes (exactly what the soy was supposed to prevent) and constipation.
The study's conclusion was that a regimen of soy isoflavones neither prevents bone loss nor reduces menopausal symptoms. ACSH's Dr. Gilbert Ross explains that the interest in soy isoflavones as an alternative to hormone replacement therapy sprang up after the 2002 Women's Health Initiative study indicated that such therapy increased a woman s risk of breast cancer and heart disease.
However, says Dr. Ross, subsequent revisitations of that study have found too many flaws in it for us to grant it any real credence. He reminds us that the standard course of estrogen replacement therapy has been shown to be very effective in treating menopausal symptoms and slowing bone loss, as well as possibly protecting against breast cancer.
The benefits, he says, really do appear to outweigh the risks.