Is Vitamin D₃ Worth Giving to Our Patients with Mild Cognitive Impairment?

Many patients with mild cognitive impairment (MCI) progress to Alzheimer disease. No preventive intervention is proven, although we tell our patients to have a healthy diet, get sleep, and exercise — and multiple supplements are advertised for “brain health.” In a randomized, placebo-controlled trial, researchers in China assessed effects of 1 year of vitamin D₃ supplementation (400 IU/day) on cognition and lipid levels in 181 patients who met criteria for MCI (mean age, 67; 45% men).

Treatment groups did not differ on history of diabetes or hypertension, mental status scores, and vitamin D levels. At the 12-month assessment, the vitamin-D group significantly improved from baseline and had better scores than the placebo group on multiple mea…