Vitamin D Supplementation Linked to 13 Percent Cognitive Improvement in Older Adults
A study of older adults with mild cognitive impairment found that taking 5,000 IU of vitamin D daily was associated with a 13 percent improvement in cognitive test scores. Researchers said the findings suggest vitamin D may play a role in supporting brain health in aging populations.
Older adults with mild cognitive impairment who took 5,000 IU of vitamin D daily showed a 13 percent improvement in cognitive test scores, according to research published in August 2026.
The study focused on adults who already had some degree of cognitive decline, a group at higher risk of developing dementia. Participants who received the vitamin D supplement performed better on standardized cognitive assessments than those who received a placebo.
Researchers said the results are encouraging but cautioned that the study does not prove vitamin D prevents or reverses dementia. Larger, longer trials are needed to confirm the findings and determine whether the benefits persist over time.
Vitamin D deficiency is common in older adults, particularly those who spend little time outdoors or live in northern climates with limited sunlight. Low vitamin D levels have previously been associated with a higher risk of cognitive decline, though the relationship has not been fully established.
The dose used in the study, 5,000 IU per day, is higher than the standard recommended daily allowance for most adults. Researchers said participants tolerated the dose well, but they advised against self-supplementing at high doses without medical supervision.
The findings add to a growing body of research on modifiable factors that may influence brain health in aging. Other recent studies have pointed to exercise, sleep quality, and social engagement as factors that may help preserve cognitive function.
Experts said the study is a useful contribution to the field but emphasized that no single supplement or intervention is likely to prevent dementia on its own.
