Too Much of a Good Thing: Calcium and Vitamin D Supplements

Many women taking vitamin D and calcium supplements may end up taking too much

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) When senior women don't get enough calcium from their diet, they may take supplements. But taking too much calcium or vitamin D in supplement form may also be problematic.

A new study found that many older women took too much calcium or vitamin D supplements, which can lead to kidney stones and other health issues.

"Ask your doctor if you should be taking any health supplements."

This study was led by John Christopher Gallagher, MD, of Creighton University in Omaha.

The study included 163 women, aged 57-90 years of age and at least seven years past menopause. All of these women had levels of vitamin D that were too low, and each took calcium supplements to reach the recommended calcium daily intake of 1,200 milligrams (mg) per day.

Calcium is needed for strong and healthy bones. The women also needed vitamin D because the vitamin helps the body protect bones and absorb calcium. Both vitamin D and calcium are considered essential for good health.

The women were randomly assigned to one of eight groups. They were either given a placebo (fake supplement), or one of seven doses of vitamin D3, from 400 to 4,800 international units (IU) per day.

The womens’ blood and urine levels of calcium were checked at the start of the study, then every three months for a year.

The final analysis included 142 women.

The researchers found that 8.8 percent of the women developed hypercalcemia (too much calcium in the blood) and 32 percent developed hypercalciuria (too much calcium in the urine).

These researchers found there was a way to predict which women would have excess levels of calcium. Women were found to be 15 times more likely to have excess calcium in their urine if a 24-hour collection of urine showed their level above 132 mg before they started on supplements. The risk for excess calcium in their urine was 20 times higher if their initial calcium urine level was above 180 mg.

In addition, every one-year increase in age reduced the woman’s risk by 10 percent, the researchers wrote.

They recommend that blood and urine levels of calcium be checked before a woman starts on supplements, and then within three months of taking supplements.

This study appeared online in Menopause June 18.

Dr. Gallagher received free calcium supplements from Bayer Healthcare. The authors made no other disclosures.

Review Date: 
June 20, 2014
Last Updated:
March 12, 2015