Diet and hormone profiles in teenage girls in four countries at different risk for breast cancer

In an attempt to assess the effects of diet on estrogen and prolactin levels, dietary histories, anthropometric measurements, and age at menarche were obtained, and Day 11 plasma and urine hormone levels measured in teenage girls in the United States (U.S.), Chile, Japan, and Papua New Guinea (PNG). Highly significant differences in diet were found, with the consumption of meat, dairy products, and fat being highest in the U.S., followed by Chile, Japan, and PNG. No significant differences in plasma levels of prolactin, estradiol, or estrone were found, suggesting that the dietary intake of meat and fat does not have a major role in determining the levels of these hormones. Subjects in PNG excreted significantly more estriol and had a significantly higher urinary estriol ratio [estriol/(estrone + estradiol)] than those in the other three countries; the Japanese and U.S. estriol ratio results were very close, with the results from Chile being intermediate (and statistically significantly different from both PNG and the U.S.-Japan results). No correlation of this pattern with any dietary component could be identified.