Women who ate four servings or more a day of a dairy product, including milk, were less likely to develop feelings of anxiety, loneliness, irritability, tearfulness and tension that characterize PMS.

A study published Monday finds that a diet rich in calcium and Vitamin D -- available in milk, cheese, yogurt and fortified orange juice -- appears to help women reduce the risk of PMS symptoms.

The findings support earlier research indicating calcium seems to help women cope with PMS. But the new study also suggests that when calcium is combined with enough vitamin D, it may help prevent PMS altogether.

"It seems that women who eat more foods high in calcium and vitamin D have less risk of experiencing PMS," said the study's lead author, Dr. Elizabeth Bertone-Johnson of the University of Massachusetts. "It's very exciting, and could end up being good news for many women out there."

She said, however, that the research is too preliminary to recommend diet changes for women in general and that more thorough studies are needed.

Nurses Health Study

Researchers say women who ate four servings or more a day of a dairy product, including milk, were less likely to develop feelings of anxiety, loneliness, irritability, tearfulness and tension that characterize PMS. Estimates are that 8 percent to 20 percent of women may have premenstrual syndrome.

The study compared the diets and supplement use over 10 years of 1,057 women, ages 27-44, who were diagnosed with PMS to 1,968 women who didn't have PMS. All the women were part of the large, long-running Nurses Health Study and answered food questionnaires and other health surveys in 1991, 1995 and 1999.

Bertone-Johnson said researchers were able to control for other factors that might affect PMS.

The study, which appears in Monday's Archives of Internal Medicine, was supported by a grant from GlaxoSmithKline, the manufacturer of calcium supplements, as well as grants from the National Cancer Institute, National Institutes of Health and the Department of Health and Human Services. A co-author, Adrianne Bendich, is an employee of GlaxoSmithKline, but the scientists said the company had no control over the study design or analysis.