Lisa Talev, Donna Hurlock, M.D., and Neal Barnard, M.D.,
examine results of the menstrual pain study at PCRM's Washington office.

For all of the symptoms of menstrual pain—headaches, backaches, water retention, irritability—there exists a cornucopia of over-the-counter medicines that promise relief. But the cause and the cure for many women may lie in the foods they eat.

A PCRM study, led by Neal Barnard, M.D., took a close look at the effect of diet on menstrual pain, following 33 women aged 22 to 48. One group was instructed, initially, to eat a low-fat, vegan diet for two months. They consumed vegetables, grains, fruits, and legumes, with no restrictions on quantity. All animal products were avoided, as well as added oils, fried foods, nuts, avocados, and olives, to create a diet made up of approximately 10 percent fat.

The results were significant. "After I changed my diet, things improved dramatically," said one study participant who had previously endured up to ten days of discomfort each month. "In the week preceding my period, I experienced virtually no premenstrual symptoms."

Among the main causes for menstrual pain are chemicals called prostaglandins, made from traces of fat stored in cell membranes. Dr. Barnard and his colleagues hypothesized that if women reduced their fat consumption, they would decrease their estrogen levels, which would in turn reduce cell growth and prostaglandin production in the uterine lining. "Our goal was to smooth out the hormonal roller coaster many women experience each month," said Dr. Barnard. The diet also increased the production of sex-hormone-binding globulin, which inactivates estrogens, thus calming the hormone swing.

Besides a decrease in the intensity of menstrual pain, the duration decreased as well, from 3.9 days to 2.7, on average. Surprisingly, the positive effects were felt by several family members who followed the diet as well. "My mother's weight and blood pressure went down. My husband lost 40 pounds that he had not been able to lose any other way. He feels healthier and more energetic than he's ever been," said one participant.

Approximately 10 percent of all women suffer such severe pain during their menstrual cycles that they are forced to miss work and other activities.

When study participants were asked to resume their normal eating habits as a second step in the study, many actually resisted. The increase in energy, improved concentration, weight loss, and pain relief were changes they wanted to keep. "I don't feel deprived on this diet," said one participant. "If I go off this diet, I feel a sense of deprivation, because I feel I'm engaging in an unhealthy lifestyle and experiencing more menstrual cramps." Women in the study lost an average of six pounds after six weeks on the vegan diet.

Dr. Barnard speculates that menstrual pain may serve as a warning sign for more serious potential health risks. Prostaglandin activity, which causes the pain, is aggravated by high levels of estrogen, which in turn come from excess fat. Fats in the foods we eat, as well what we carry on our bodies, all cause estrogen levels to rise. The result is seen in higher cancer rates in women on fattier diets or with excess body fat, and a worse prognosis when cancer strikes. A low-fat, plant-based diet is the healthiest way to keep hormones in equilibrium.

Barnard ND, Scialli AR, Hurlock D, Bertron P. Diet and sex-hormone binding globulin, dysmenorrhea, and premenstrual symptoms. Obstet Gynecol 2000 Feb;95(2):245-50.