Calcium to quell premenstrual syndrome?

AT FIRST GLANCE it seems like a godsend for women who suffer the mood swings, bloating and breast tenderness, food cravings, and body aches of premenstrual syndrome, or PMS. In a study of more than 400 women ages 18 to 45 who suffered from the condition, those who were given 1,200 milligrams of calcium a day experienced a 48 percent reduction in symptoms. The researchers, based at St. Luke's Roosevelt Hospital Center in New York, theorize that calcium influences PMS severity by acting on various hormones.

Before you go reaching for the calcium tablets, however, there are some caveats to consider. One is that women who were given placebo pills without any calcium also underwent a significant reduction in PMS symptoms. Their discomfort after three monthly cycles of treatment declined by 30 percent. "That's a relatively small difference" in relation to the 48 percent decline seen with calcium, says Robert Reid, M D, a leading PMS researcher at Queen's University in Kingston, Ontario.

Why would a placebo help at all? It's well-known in scientific circles that just being given a treatment can have a powerful pain-reducing effect.

Also at issue is how well the women were "blinded" to whether they were taking calcium or placebo pills. The calcium was in the form of Tums, which has a distinctive texture and flavor. Even though this was a study in which neither the researchers nor the subjects were supposed to know who was getting what, if the Tums-taking women had any inkling that they were in the non-placebo group, they might have been more likely to report a reduction in symptoms.

Another potential limitation is that if the women's PMS made them extremely uncomfortable, they were allowed to take pain killers. That's only right, of course, but it makes it harder to determine in some cases if it was the calcium or the analgesic that was diminishing PMS pain.

There's "no harm in trying" calcium supplements if you have PMS and nothing else has worked, says Dr. Reid. But the study results would have to be replicated by other researchers before it could be said with any certainty that calcium does in fact play a role in mitigating symptoms.

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