Eating tofu, soy and other foods high in vegetable protein cuts the risk of an early menopause by up to nearly 60 per cent, a major study has found.
Around one in ten women in Britain reach the menopause before the age of 45, which increases their risk of heart disease, osteoporosis and early cognitive decline.
Experts have assumed this is a quirk of genetics which some women cannot avoid, particularly those who also reached puberty early.
But research suggests women can lower their risk of reaching the menopause early by altering their diet and sticking to it.
Scientists from Harvard School of Public Health in Boston and University Of Massachusetts at Amherst found that high consumption of vegetable protein was linked to a significantly lower risk of early menopause.
They tracked 116,000 women from 1991 to 2011 until they were all post-menopausal.
Those whose calorific intake included at least 9 per cent vegetable protein such as tofu, soy, nuts, brown pasta, brown rice and whole grains had a 59 per cent lower risk of an early menopause than those for whom vegetable protein made up less than 4 per cent of their diet. Meat protein was not found to have the same effect. The researchers, whose work is published in the American Journal of Epidemiology, said vegetarians are most likely to eat this much vegetable protein.
But those women who follow a flexitarian' diet becoming vegetarian a few days a week are also likely to benefit.
Figures last year from consumer analyst Mintel revealed that 35 per cent of Britons eat meat-free meals several times a week, finding alternative sources of protein such as nuts, grains and tofu.
The menopause, which occurs on average at the age of 51, happens when the body stops naturally producing oestrogen and other sex hormones, ending a woman's reproductive life.
The scientists suspect vegetable protein which is in a different form to meat protein protects the ovaries and reduces depletion of the follicles, which are key to the reproductive process.
They think that if they can work out exactly how this happens, they may eventually be able to help prevent early menopause.
The authors wrote: A better understanding of how dietary vegetable protein intake is associated with ovarian ageing may identify ways for women to modify their risk of early onset menopause and associated health conditions.'
The researchers said very few women in the study actually met the 9 per cent dietary requirement that reduced their risk by 59 per cent. But 20 per cent of women got 6.5 per cent of their calories from vegetable protein enough to reduce their risk of early menopause by 16 per cent.
They wrote: For a woman with a 2,000-calorie diet, this is equivalent to 32.5 grams of vegetable protein per day, or three to four servings of protein-rich foods such as enriched pasta or breakfast cereal, tofu and nuts.'
A previous study, published in the JAMA medical journal last year, found that women who experienced early-onset menopause were 50 per cent more likely to suffer coronary heart disease, 11 per cent more likely to die as a result of a heart attack, and 12 per cent more likely to die early from any cause.
But the benefits of a flexitarian' or vegetarian diet extend beyond women and early menopause.
Research published by the University of Navarra in Spain in May revealed eating one or two meat-free meals a week halves the risk of becoming obese.
That research, which involved tracking 16,000 people over a decade, found that eating just 25 per cent less meat every week was linked to a reduction in the risk of obesity by 43 per cent.
© Daily Mail