Wondering if Milk Works Against PMS

Yes, dear California Milk Processor Board, I am feeling witchy. But it has nothing to do with premenstrual syndrome. Instead, it's from watching your new Spanish-language commercial in which a bruja (Spanish for "witch") representing a woman with PMS flies through the forest, threatening children and even turning two men into pigs. That is, until she discovers milk, drinks it, and—symptoms eased—turns into a hot babe with a sweet temperament.

The ad is pretty lame—can't we discuss PMS in a serious way without reducing symptomatic women to terrorizing crones? But I was interested in the health claim that drinking milk can alleviate the symptoms associated with PMS, like headaches, water retention, and, of course, mood swings. The milk board cites a study in the American Journal of Obstetrics and Gynecology, saying that calcium in milk can ease PMS. I found the study, published in 1998, which evaluated 466 women between the ages of 18 and 45 with a history of moderate to severe PMS symptoms, namely pain, water retention, food cravings, and negative affect (medicalspeak for being in a bad mood). One group took a daily supplement containing 1,200 milligrams of calcium; the other got a placebo. And after three menstrual cycles, the calcium group reported greater relief of symptoms than the placebo group.

Note that the study looked at the impact of calcium, not milk itself. (An 8-ounce serving of milk has about 300 milligrams of calcium, which means you'd have to drink four glasses to get 1,200 milligrams of calcium from milk alone.) But milk itself may also help—possibly even to prevent PMS in the first place. In 2005, researchers at the University of Massachusetts-Amherst found that higher intakes of dietary calcium and vitamin D (which promotes calcium absorption), as well as skim or low-fat milk, were associated with, though not necessarily the cause of, a lower risk of developing PMS. That study was published in the Archives of Internal Medicine.

Susan Thys-Jacobs, an endocrinologist at St. Luke's-Roosevelt Hospital Center in New York, was the lead author of the 1998 study. That and subsequent research have convinced her, she says, that the complex interplay of hormones during the latter part of the menstrual cycle sends many women into a relative state of calcium deprivation, which actually prompts the symptoms. "The body is screaming out for calcium," she says. (She and her husband formed a company to market their own supplement, Premcal.)

So there is evidence that calcium and vitamin D may prevent or lessen the symptoms of PMS, at least for some people. If you do decide to take the milk board's advice and trade your broomstick for a glass of milk, stick to the low-fat or skim dairy products. The 2005 study found that whole milk was associated with a higher risk of PMS, possibly because of its saturated fat content. Moreover, an 8-ounce glass of whole milk has about 150 calories. Skim milk, by contrast, has about 80 calories a serving and no fat.

And remember that there are plenty of other sources of calcium, if you're lactose intolerant, a vegan, or simply don't like milk. The Harvard School of Public Health has a nice summary of the science behind calcium and milk, with a list of other calcium-rich foods at the bottom of the page. Here's a list of food sources of vitamin D. Meanwhile, the Physicians Committee for Responsible Medicine, which advocates vegetarianism, has other nondairy tips on nutrition and PMS. And if you decide to go the supplement route, it's best to check with your doctor to make sure you aren't taking too much. Excessive calcium and vitamin D intake can cause constipation and heart problems and can interfere with other medications.