Study shows modest but significant lower risk
Results of a new study from epidemiologists at the University of Massachusetts Amherst and Harvard T.H. Chan School of Public Health suggest that long-term, high intake of vegetable protein from such foods as whole grains, soy, and tofu, may protect women from early menopause and could prolong reproductive function.
“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,” write first author Maegan Boutot, with her advisor, Professor Elizabeth Bertone-Johnson. Details appear in the current online edition of the American Journal of Epidemiology.
According to the authors, early menopause or the cessation of ovarian function before age 45, affects about 10 percent of women and is associated with higher risk of cardiovascular disease, osteoporosis, and early cognitive decline. Few studies have evaluated the link between protein intake and menopause timing, and this is the first to look specifically at early menopause.
Researchers evaluated the relationship between diet and risk of early menopause among members of the Nurses’ Health Study II (NHS2), an ongoing prospective study of 116,000 women aged 25-42 when they entered it in 1989.
Participants were asked to report the frequency of consumption in a single serving of 131 foods, beverages and supplements over the previous year, from “never or less than once a month” to “6+ per day.” They observed that women consuming approximately 6.5 percent of their daily calories as vegetable protein had a significant 16 percent lower risk of early menopause compared to women whose intake was approximately 4 percent of calories.
Relatively few women in the study consumed high levels of vegetable protein and analyses was limited, women consuming 9 or more percent of their calories from vegetable protein had a hazard ratio of 0.41 (95 percent confidence interval = 0.19-0.88) compared to those eating less than 4 percent.
The authors suggest that more prospective studies of their findings are warranted, including soy-based and non-soy vegetable proteins comparison.