Rutgers Study Finds Moderate Vitamin D Boosts Memory but May Slow Reaction in Older Women

Researchers at Rutgers University conducted a year‑long trial with overweight or obese women aged 50 to 70 in the United States. Participants were assigned to take either 600 IU (the standard recommendation), 2,000 IU, or 4,000 IU of vitamin D daily while also following a weight‑loss program.

After twelve months, the group receiving 2,000 IU performed better on tests of memory and learning than those on the standard dose, indicating a moderate increase may support certain cognitive functions. However, the same dose, and especially the 4,000‑IU dose, was linked to slower reaction times during testing. Slower responses can elevate the risk of trips, falls, and related accidents among older adults.

The findings suggest that higher vitamin D supplementation is not universally beneficial and that optimal dosing for brain health requires further investigation, including gender differences, direct links between reaction speed and fall risk, and identification of populations that might gain the most from supplementation.