Eating tofu, soy
and other foods high in vegetable protein cuts the risk of an early menopause
by up to nearly 60 percent, a recent major study has found.
About 10% of all women reach the menopause early, 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 percent of citizens of Britain 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 estrogen 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 percent dietary requirement that reduced their risk by 59 per cent.
But 20 percent of women got 6.5 percent of their calories from vegetable
protein - enough to reduce their risk of early menopause by 16 percent.
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 percent
more likely to suffer coronary heart disease, 11 percent more likely to die due
to a heart attack, and 12 percent more likely to die early from any cause.
But the benefits of a flexitaria' 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.
The team found no similar associate between a lower risk
of early menopause and eating animal sources of protein.
The authors now suggest that more research should be
carried out, including studies to compare soy-based and non-soy vegetable
proteins.
"A better understanding of how dietary vegetable
protein intake is associated with ovarian aging may identify ways for women to
modify their risk of early onset menopause and associated health
conditions," commented first author Maegan Boutot, with her advisor,
professor Elizabeth Bertone-Johnson.
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