A year long study has found that isoflavones given to premenopausal women does not affect their ovulatory cycles.
Investigators undertook the study in light of indications that isoflavones phytoestrogens contained in soy foods, may play a role in the prevention of breast cancer.
In a randomized double-blind trial, researchers from the Cancer Research Center, Honolulu. Hawaii, and the University of California at Los Angeles, studied the one year ovulatory cycles among 34 premenopausal women. The two groups were comparable at baseline except for a small difference in age.
The women were given 100 mg of isoflavones a day, or placebo. The investigators assessed compliance with the regimen by measuring increased isoflavone in the urine of women in the intervention cohort.