A new study from researchers at the University of Missouri-Columbia reveals that soy protein could be the secret weapon against the side effects of menopause - in particular, the effects of menopause on metabolic and bone health. The findings of the study may also mean a new way to protect the bone strength of women who have not yet experienced menopause.
Menopause is that natural decline in the production of reproductive hormones that develops when a woman reaches her 40s or 50s.
A woman is officially diagnosed with menopause when she goes without menstruating for 12 consecutive months.
The effects of menopause include the development of bothersome symptoms such as hot flashes, night sweats, mood swings, and changes in hair and skin quality. Less known but more severe effects develop, too, and affect both the bone and metabolic health of many women after menopause.
"Women in menopause often face unexpected changes in their health as a result of the changes in their hormones. Some of these changes can be very serious," said Dr. Alqulali, a Bettendorf, Iowa, OB-GYN.
One of these effects is the development of osteoporosis, a condition that causes the bones to become brittle and fragile. Women who develop osteoporosis are at risk of fractures. As a result of osteoporosis, many women are forced to decrease their activity levels.
"The risk of fracture increases in the years after menopause. Serious cases of osteoporosis can cause spinal compression fractures, too," Alqulali said.
The impacts of menopause on the metabolic health include weight gain, especially in the abdominal area; an increased risk of developing type 2 diabetes; and the development of dyslipidemia, which causes high levels of fats and cholesterol in the blood.
The effects of menopause on a woman's metabolic health can lead to an increase risk of a cardiovascular event, such as a heart attack or stroke. In fact, nearly half of all deaths in women over the age of 50 are due to heart attack.
The combination of negative bone and metabolic health effects caused by menopause can severely impact the health of postmenopausal women and further drives the need for new treatments.
The researchers from the University of Missouri have answered the call.
During the study, the researchers gave groups of rats with ovaries and rats without ovaries - modeled after menopausal women - both soy- and corn-based diets.
They compared the effects of both the diets on the rats and found that the rats without ovaries that were given a soy-based diet had improved bone strength compared to the rats without ovaries that consumed a corn-based diet.
Soy has been found to reduce cholesterol levels and lower blood sugar, which could improve heart health and lower the risk of diabetes.
The tibia bones of the soy-fed rats, both with and without ovaries, were stronger than either group of the corn-fed rats.
The researchers also found that soy-fed rats saw improvements in metabolic function regardless of the presence of ovaries.
The study authors believe that these two revelations may benefit women before menopause, too.
The researchers found that the tibia bones of the rats that were fed the soy-based diet were stronger compared to the rats who were fed the corn-based diet, regardless of whether they had their ovaries. Moreover, they found that the soy-based diet also improved the metabolic function of the rats both with and without ovaries.
"Improving bone strength before menopause may mean less of an impact when menopause hits," Alqulali said.
Earlier studies also suggest that soy may help reduce the frequency of hot flashes.
Foods that contain soy protein include edamame and soybeans, tofu, soy milk, soy nuts, tempeh, and miso, a paste made from fermented soybeans used in Japanese cooking.
"In addition to consuming soy, women should also consume foods rich in calcium and vitamin D to support bone health," Alqulali said.
WebMD. Menopause and Heart Attack. 2018.
University of Missouri-Columbia. "Soy diets might increase women's bone strength." ScienceDaily. ScienceDaily, 7 August 2018.