Your residents who take vitamin D because they think it will delay functional decline may be in for a surprise. Newly published research in JAMA Internal Medicine finds that those who take higher monthly doses of the supplement have an increased risk of falls and, in fact, experience no benefit as to the function of their lower extremities.

The 200 participants in the one-year study, conducted by researchers at the University Hospital Zurich in Switzerland, were divided into three groups. Members of one group received 60,000 international units of vitamin D3 per month; members of another group received 24,000 IU of vitamin D3 plus calcifediol, a form of vitamin D, per month; and members of the control group received 24,000 IU of vitamin D3 per month. The control group dosage is what is recommended by the Institute of Medicine’s Food and Nutrition Board for adults aged 71 or more years and by the Endocrine Society for those aged more than 70 years, although the Vitamin D Council recommends four times that amount.

Of the 200 participants, 60.5% (121 of 200) fell during the 12-month treatment study period. The 60,000 IU or 24,000 IU plus calcifediol groups had higher percentages of participants who fell (66.9% and 66.1%, respectively) compared with the control group (47.9%). The 60,000 IU and 24,000 IU plus calcifediol groups also had a higher average number of falls (1.47 and 1.24, respectively) compared with the control group.

“High monthly doses of vitamin D or a combination of calcifediol may not be warranted in seniors with a prior fall because of a potentially deleterious effect on falls,” the authors write. “Future research is needed to confirm our findings for daily dosing regimens.”

In a related commentary in the same issue of JAMA Internal Medicine, Steven R. Cummings, M.D., of the California Pacific Medical Center Research Institute in San Francisco, and coauthors write that vitamin D supplementation has not been proven to reduce the risk of falls and fractures and, until it is, older adults should strive to meet the IOM’s recommendation of 800 IU per day (or 24,000 IU per month) through a balanced diet. Foods high in vitamin D, according to the National Institutes of Health, include fortified milk, cereals, yogurt and orange juice, as well as fatty fish such as salmon, tuna and mackerel.