HORMONE replacement therapy slashes the risk of women developing diabetes by more than a third, according to new research today.
Oestrogen supplements boost chemicals that maintain blood sugar levels, suggests the study.
Researchers also identified that just one of three oestrogen proteins, or receptors, is involved in the mechanism.
They say this could lead to the development of a diabetes treatment that would also benefit men.
It would be possible to develop a molecule that only activates the specific receptor, with a much more targeted effect.
Study first author Dr Sandra Handgraaf, of the University of Geneva in Switzerland, said: “One could imagine a treatment that, without the side effects of a little too powerful hormonal therapy, would also address men.”
Taking oestrogen can cause bloating, breast tenderness, swelling, nausea. cramp, headaches, indigestion and bleeding in women.
It is known younger women are less likely than men to develop type 2 diabetes, the form caused by an unhealthy lifestyle. But after the menopause, the trend reverses dramatically.
The reason is the protective role of the sex hormone oestrogen on metabolism, and in particular its link with glucagon and GLP1 that control glucose.
Dr Handgraaf said: “A number of scientists are working on the effect of oestrogens on pancreatic insulin-producing cells.
“But its effect on glucagon-producing cells, another hormone regulating blood sugar, had never been explored before.
“Indeed, if the pancreas secretes insulin, it also secretes glucagon, a hormone with the opposite effect. Insulin captures sugar, while glucagon releases it.
“Diabetes is therefore due to an imbalance between these two hormones controlling the sugar level in the blood.”
The study said a woman on HRT is up to 35 percent less likely to develop type 2 diabetes.
When the researchers injected post-menopausal female mice with oestrogen it increased their tolerance to glucose, reducing diabetes risk.
They were surprised by the effect on glucagon and especially GLP1, an intestinal and pancreatic hormone that increases insulin production.
Alpha cells in the pancreas then secreted less glucagon, too much of which causes hyperglycaemia or high blood sugar, but more GLP1.
The findings, published in JCI Insight, were also confirmed on human cells and tissue samples.
The researchers said HRT is often subject to negative publicity, mainly because of the cardiovascular risks associated with it.
Study leader Prof Jacques Philippe, a diabetes specialist at Geneva University Hospitals, said: “It is important to remember hormonal substitution, when taken at the beginning of menopause and for a few years only, does not cause any particular risk of cardiovascular events.
“However, if hormonal treatment is taken more than 10 years after menopause, the cardiovascular risk is effectively increased.