Environmental gynecomastia

In this article, Drs. Martinez and Lewi describe a 60-year-old man who developed gynecomastia associated with high serum estradiol and estrone levels. After an extensive evaluation, they concluded that the etiology was an enormous intake of soy milk -- 3 quarts per day -- which was estimated to provide 361 mg of phytoestrogens, composed primarily of the isoflavones genistein and daidzein. After discontinuing the soy milk, the estrogen levels gradually returned to normal and the patient's mastodynia resolved. Although it is possible that the gynecomastia was the result of the massive phytoestrogen ingestion, phytoestrogen intake cannot explain the elevated estradiol and estrone levels for 3 reasons. First, the authors state that the estrogens were measured by liquid chromatography/tandem mass spectrometry. As recently reviewed, there are a multitude of environmental contaminants that can affect both male and female reproductive function, including some that decrease testosterone as well as estrogen-like substances. In addition, a number of causes or presumed causes of environmental gynecomastia have been described in the literature.