Calcium supplements won't help men cut cholesterol or trim fat, but they could help those who don't get enough calcium in their diet to keep their blood pressure under control, new research shows.
Calcium supplements are widely recommended to women after menopause to maintain bone health, and can keep men's skeletons' strong too, Dr. Ian R. Reid and colleagues from the University of Auckland in New Zealand note in the American Journal of Clinical Nutrition.
There's also some evidence that getting extra calcium could lower levels of cholesterol and other harmful blood fats, aid in weight loss, and reduce blood pressure, they add, but this has yet to be investigated "rigorously" in men.
To do so, the researchers randomly assigned 323 healthy men over age 40 to take 600 milligrams of calcium daily, 1,200 milligrams of calcium a day, or a placebo for two years.
Calcium supplements didn't change the ratio of good to bad cholesterol; body weight; fat or muscle mass; triglyceride levels; or total cholesterol levels, the researchers found.
While there were "downward trends" in blood pressure among the men who took calcium, these weren't statistically significant.
But when the researchers looked separately at the men who consumed the least calcium (below 785 milligrams a day), there were "borderline" effects on blood pressure among men taking 1,200 mg of calcium in supplements; these men showed a four-point drop in systolic blood pressure (the top number), and a three-point drop in diastolic blood pressure (the bottom number). Similar effects were seen among the men who consumed the least magnesium at the study's outset (less than 392 milligrams per day).
Studies have shown a "small beneficial effect" of calcium on cholesterol levels in women after menopause, the researchers note, but the same doesn't appear to be true in men, although it isn't clear why.
The therapeutic value of calcium in managing high blood pressure is "likely to be small and insufficient to justify its routine use" in patients whose calcium intake is average, Reid and colleagues conclude.
"However, selective supplementation in those with low dietary intakes could be considered," they add.