New studies on mice have found that a hormone involved in sexual development in older women can lead to weight changes, “from a pear shape to an apple shape”.
Last week, we reported in other news that pear-shaped women are at lower relative risk of type 2 diabetes, according to another weight-related study.
Researchers believe this may be because the hips and thighs store up fat and prevent it from moving to organs such as the liver and heart, which can lead to chronic health conditions.
Other scientists looking at BMI, fat distribution and heart risks also found, in line with earlier results, that reduced accumulation of fat in the lower body of people with a normal BMI puts them significantly more at risk.
The work around follicle-stimulating hormone (FSH) and weight regulation began with Dr. Mone Zaidi, a professor of medicine, at the Icahn School of Medicine at Mount Sinai in New York City.
In the latest studies, he and other researchers have described in The New England Journal of Medicine and Cell Metabolism how rising levels of the reproductive hormone FSH affects weight and possibly even bone density.
It was long believed that the role of FSH, whose levels soar as women’s ovaries start to fail just before menopause, was limited to helping in the production of eggs in women and to stimulate the ovaries to release the hormone oestrogen.
However, it has come to light recently that FSH appears to be responsible for a spontaneous redistribution of fat in middle age to the abdomen, which presents risks if that fat is primarily stored as visceral fat, near vital organs, in women.
When researchers did try blocking FSH, they observed that more calories are being burned and abdominal fat is reduced.
The evidence for FSH and weight is stronger and a study published last month in the NEJM already suggests that blocking the risk of FSH in menopausal women could prevent fat gain.
Dr Zaidi’s team also came up with a theory that might explain fat loss in mice in which F.S.H. is blocked. In the experimental mice, white fat was being converted to its more metabolically active kind, brown fat.
It’s unclear as to whether FSH is the sole cause and if these results also apply to humans, but the idea has some credibility and many researchers have now turned their focus to the link between obesity and the interplay of hormones.

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