MONDAY, June 13, 2005 (HealthDayNews) -- A diet rich in calcium appears to reduce the risk of developing PMS by as much as 40 percent, researchers report.
Most women experience mild premenstrual symptoms, but for 8 percent to 20 percent the symptoms can be severe. These symptoms define PMS and can interfere with daily activities and relationships, according to the report in the June 13 issue of the Archives of Internal Medicine.
Earlier studies have found that calcium supplements and vitamin D, which aids the absorption of calcium, may reduce both the occurrence and severity of PMS. The latest study appears to confirm those findings.
"Our findings do suggest that high dietary intake of calcium and vitamin D may help women by preventing the initial development of PMS," said study author Elizabeth R. Bertone-Johnson, an assistant professor of epidemiology at the University of Massachusetts, Amherst.
To find out the effect of dietary calcium on PMS, Bertone-Johnson's team collected data on women with and without PMS. "We compared the dietary intake of calcium and vitamin D in 1,057 women in the Nurses Health Study II who had developed PMS over a 10-year period with 1,968 women who did not develop PMS," she said.
The comparison showed that calcium intake had a profound effect on whether women developed PMS. "We found that women with the highest intakes of vitamin D and calcium from food sources did have a significantly reduced risk of being diagnosed with PMS," Bertone-Johnson said.
The largest result was seen in women who consumed about 1,200 milligrams of calcium and 500 IU of vitamin D per day. "We found the women who consumed four servings per day of skim or low-fat milk, fortified orange juice and low-fat dairy foods, such as yogurt, had approximately a 40 percent lower risk of being diagnosed with PMS, than women who only consumed these foods about once per week," she said.
Increasing the intake of calcium and vitamin D might produce this result by affecting estrogen levels during menstruation, Bertone-Johnson said. Levels of calcium and vitamin D fluctuate across the menstrual cycle, and this might define women with and without PMS, she added.
The findings should encourage women to eat more foods rich in calcium and vitamin D, Bertone-Johnson said. "Women might consider increasing their dietary intake of these nutrients," she said. "We also feel that clinicians may consider recommending these nutrients to women because they have also been associated with other health benefits, such as the reduced risk of osteoporosis and some cancers."
One expert viewed the finding with caution, however. "I don't think that this is going to explain all women who have PMS," said Ellen W. Freeman, a research professor in the Departments of Obstetrics and Gynecology and Psychiatry at the University of Pennsylvania's School of Medicine, Philadelphia. "I am very skeptical that it [low calcium intake] is a major cause of PMS."
However, Freeman believes that for most women, increasing calcium and vitamin D intake can't hurt, even though it might not help reduce the occurrence or severity of PMS. "Overall, in this country women don't have enough calcium," she said.
Another expert found the report interesting, but cautioned that it doesn't apply to all premenstrual problems. "The findings are very interesting and very positive for treating disorders in women," said Dr. Margaret Spinelli, an associate clinical professor of psychiatry at Columbia University in New York City.
Spinelli notes that one should not confuse PMS with premenstrual dysphoric disorder (PMDD). "Premenstrual dysphoric disorder is rare," she said. "It's about 3 to 5 percent of women, whereas up to 90 percent of women have PMS."
For women with PMDD, the symptoms resemble those of major depression, Spinelli said. "That's more serious," she said. "PMS has more to do with physical symptoms, such as breast tenderness, bloating and headache. But if you can find something to relieve these symptoms without taking other medication, that's a benefit."
The National Women's Health Information Center can tell you more about premenstrual syndrome and premenstrual dysphoric disorder.