Soy may strengthen bones before and after menopause

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Soy protein in food might be a way to counter the negative effects of menopause on bone health—and may also have benefits for women who haven’t yet reached menopause, a study with rats shows.

Osteoporosis, decreased physical activity, and weight gain are serious health concerns for postmenopausal women, researchers say.

“The findings suggest that all women might see improved bone strength by adding some soy-based whole foods, such as tofu and soy milk, to their diet,” says Pamela Hinton, professor of nutrition and exercise physiology at the University of Missouri. “We also believe that soy-based diets can improve metabolic function for postmenopausal women.”

For a new study, which appears in Bone Reports, researchers looked at the effects of soy versus corn-based diets on rats selectively bred to have low fitness levels. They again divided rats between those with and without ovaries to mimic effects of menopause. They compared the impact of the soy diet on bone strength and metabolic function to rats fed a corn-based, soy-free diet.

“…women don’t even need to eat as much soy as is found in typical Asian diets…”

“Prior research has shown that these rats are good models, as average American women are relatively inactive both before, and especially after, menopause,” says coauthor Victoria Vieira-Potter, associate professor of nutrition and exercise physiology.

“As such, understanding how dietary protein sources, such as soy, can impact metabolism and bone health in these rats can help us better understand how such diets might impact women’s health across the lifespan.”

The tibia bones of the rats that were fed soy were stronger compared to the rats who were fed the corn-based diet, regardless of ovarian hormone status, the researchers found. Moreover, the soy-based diet also improved metabolic function of the rats both with and without ovaries.

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“Bottom line, this study showed that women might improve bone strength by adding some soy-based whole foods to their diet,” Hinton says.

“Our findings suggest that women don’t even need to eat as much soy as is found in typical Asian diets, but adding some tofu or other soy, for example foods found in vegetarian diets, could help strengthen bones.”

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Additional researchers from the University of Missouri and from the University of Michigan Medical School contributed to the study.

The National Center for Complementary and Integrated Health, the Office of Dietary Supplements, and the National Cancer Institute supported the work.

Source: University of Missouri