Study: Carnivore Diet May Trigger Girls' Early Puberty

(June 11) -- High-meat diets among young girls may lower the age at which they reach puberty, potentially putting them at greater risk for life-threatening diseases, according to a new British study.

The University of Bristol study, published in the latest issue of Public Health Nutrition, shows that girls who ate more meat and protein at the ages of 3 and 7 were more likely to have started menstruating by the age of 12 1/2 years.

The early onset of puberty puts women at greater risk of developing diseases including breast cancer, ovarian cancer and heart disease.

"These results add to the evidence that it is healthiest to avoid diets containing very high amounts of meat," Imogen Rogers, the report's author, said on the university website.

A 2007 study found that girls had been reaching puberty earlier and earlier throughout the 20th century. A 21st-century girl, on average, will develop breasts a full one to two years earlier than a girl in the late 1960s.

"Over the course of just a few decades, the childhoods of U.S. girls have been significantly shortened," said the report, which was commissioned by the Breast Cancer Fund.

Puberty in girls is triggered by the brain activating a signal pathway to the ovaries and adrenal gland. Research indicates that possible reasons for earlier signaling include stress, excessive TV watching and now meat intake.

The possibility of a connection between obesity and early onset of puberty has long been raised, but the details are not clear. Puberty can be a cause of obesity as well as a consequence.

For her research on meat eating and puberty, Rogers studied 3,000 girls taking part in the University of Bristol's "Children of the 90s" study. She found that 49 percent of girls eating more than 12 portions of meat a week had reached puberty by the age of 12 1/2.

For girls eating less meat, the figure was 35 percent.

Still, Rogers stopped short of calling for girls to cut out meat altogether.

"Meat is a good source of many important nutrients including iron and zinc," Rogers said. "There is no reason why girls should adopt a vegetarian diet."

Rogers is a senior lecturer in pharmacy and biomolecular sciences at the University of Brighton in the United Kingdom.