Many articles have been written and published in scientific journals over the past few wondering what is causing modern girls to reach puberty earlier than previous generations. Many have wondered if it’s due to chemicals in plastics, or estrogen getting into the water as women on the pill flush chemicals that make it into their urine down the toilet; now however, researchers at the University of Wisconsin suggest it has to do with girls eating more than prior generations of girls. The research came about, the authors write in their paper published in Endocrinology, due to noticing that rhesus monkeys used in research projects over the past thirty years at the University have also come to reach puberty earlier than previous generations.
Suspecting that it might have more to do with how much the monkeys were fed (because University records indicated that in recent years the monkeys had been fed more) rather than other environmental factors, the research team began recording caloric intake of several of the monkeys over several generations. One group was fed the same amount they had been over the past several years; the other was fed slightly less. After several generations of monkeys had been born, the team noticed a direct correlation between caloric intake and early onset puberty.
While this experiment doesn’t conclusively prove that eating more causes early puberty in humans, it does seem to offer ample evidence. The team notes that average onset of menarche for girls has dropped from age 12 to 8 over the past century and a half and has for many led to emotional development problems.
The authors suggest that parent’s not wait for conclusive studies on humans to prove that early puberty is the result of overeating and begin monitoring the caloric intake of their daughters immediately. Not only does eating too many calories likely lead to early age menarche, but it can also lead to obesity, diabetes and other chronic illnesses.
The team suggest the results of their study not only highlights the impact of young females eating too many calories but also shows that humans have a tendency to come to see it as the norm, and thus begin to feed captive animals such as the monkeys more, without having any actual reason for doing so. In the process they may be adding an unknown factor to the monkey’s physical makeup that could be skewing the results of the studies they are doing using the monkeys as guinea pigs.