It’s well-documented that girls today reach menarche earlier than previous generations. A century ago, it was common to experience one’s first period at 16 or 17; today, that’s regarded as so late that medical examinations are often conducted to reassure parents and girls that their development is normal. The typical North American girl sees her first period at age 12, give or take a few months.
Many explanations have been posited for this phenomenon; personally, I’ve long suspected that a primary cause is endocrine disruptors that are the hormones used in raising beef and dairy cattle as well as chicken in this country. Also, girls today typically achieve the minimal body fat necessary to menstruate at younger ages, due to improved health and nutrition. Now a new study suggests that it is not merely consumption of meat that lowers the age of menarche, but the high content of zinc and iron in a meat-rich diet.
Oddly, the lead researcher is quoted in the news story as saying, “These results add to the evidence that it is healthiest to avoid diets containing very high amounts of meat,” but also that there is no need for young girls to cut their meat intake. (I haven’t yet been able to locate a copy of the actual study.)