Calcium and Vitamin D Supplements Could Risk the Health of Older Women

You may want to hold off on those calcium and vitamin D supplements if you're a bit older. Scientists have found that usual supplements may have a bit too much punch for older women and may send calcium excretion and blood levels too high.

In order to examine the impact on supplements on older women whose vitamin D levels were too low, the researchers conducted a placebo-controlled trial on 163 women between the ages of 57 to 90. The women took calcium citrate tablets in order to meet their recommended intake per day, and also took various doses of vitamin D that ranged from 400 to 4,800 IU per day.

So what did they find? About 9 percent of the women developed excess levels of calcium in their blood, a condition called hypercalcemia. A total of 31 percent developed excess levels in their urine, which is known as hypercalciuria, even though they were taking normal doses of the supplements and did not have hyperparathyroidism, a condition in which the body makes too much calcium-regulating hormone. These excess calcium levels could potentially lead to kidney stones or other problems.

"Even a modest calcium supplementation of 500 mg/day may be too high for some women," wrote the authors in a news release.

That said, there's a way to predict which women are likely to develop these excess levels. The risk of developing excess urine calcium was 15 times higher for women who started out with a 24-hour urine calcium level above 132 mg than for women with lower levels. In addition, the risk was 20 times higher for women who started with levels above 180 mg than for women with lower levels. Interestingly, every one-year increase in age reduced the risk by 10 percent.

The findings reveal the importance of determining how much calcium women typically receive through food sources before taking a calcium supplement. In the end, women may not need nearly as much as they think they do.

The findings are published in the journal Menopause.