Environmental Factor, February 2006, National Institute of Environmental Health Sciences
Soy Products May Cause Reproductive Problems
Genistein, a major component of soy, was found to disrupt the development of the ovaries in newborn female mice given the product. This study, published in the January issue of Biology of Reproduction, adds to a growing body of literature on potentially adverse consequences of genistein on the reproductive system.
News articles on the study appeared in web, electronic and print publications across the United States and in some international media. United Press International circulated the story to news organizations.
Genistein is the primary naturally occurring estrogen in plants, called phytoestrogens, and can mimic the effects of estrogen in the body. It is found in soy-based infant formulas and over-the-counter dietary supplements.
NIEHS researchers collaborated with an investigator at Syracuse University. The study found effects at all exposure levels. Mice injected with the highest dosage were infertile, and mice receiving the lowest doses had fewer pups and fewer pregnancies.
NIEHS researcher and lead author Wendy Jefferson said the study suggests genistein inhibits egg cell separation.