A hypothesis on the etiological role of diet on age of menarche.

Body size and body composition have been suggested as the best explanation for the temporal trend toward early menarche over the last 100 years. There is evidence from human and animal studies that indicates that body size is not the primary factor in influencing the occurrence of menarche. The data actually show that diet may be a primary environmental control mechanism of menarche especially since it alters hormone levels. We see diet as an etiological factor in both the long term and immediate control of menarche. In the long term it influences body size and development leading to menarche. In the short term it acts at a critical state to precipitate the onset of menarche and related physiological changes. This hypothesis does not exclude other less important factors associated with menarche. Our data shows that the present trend toward early menarche can be reversed when a balanced vegetarian diet is selected in place of the ordinary American diet.