Usefulness of phytoestrogens questionable

October 1, 2007

In an effort to determine the value of phytoestrogens in clinical practice, Austrian researchers analyzed six systematic reviews and meta-analyses of 25 randomized, controlled trials (RCTs).

In an effort to determine the value of phytoestrogens in clinical practice, Austrian researchers analyzed six systematic reviews and meta-analyses of 25 randomized, controlled trials (RCTs).

Generally, they found the results contradictory and the findings of the meta-analyses to demonstrate no statistically significant reduction in vasomotor symptoms. However, one systematic review of five RCTs found that in a select population of women-those in early and natural postmenopause with mild-to-moderate vasomotor symptoms-five out of the five studies found a significant reduction in hot flashes. And a meta-analysis of 21 studies found a significantly reduced risk of breast cancer in past users of phytoestrogens.

While various RCTs report favorable effects on bone mineral density, vasodilation, platelet aggregation, insulin resistance, and serum concentrations of triglycerides, high-density lipoprotein, and low-density lipoprotein, no study proves an actual protective effect against the endpoints of breast cancer, bone fracture, or cardiovascular events.