As the global population ages and the risk of Alzheimer’s disease increases, identifying lifestyle factors that may prevent or forestall the disease is becoming increasingly important. A recent study found that people who take vitamin D supplements are 40% less likely to develop Alzheimer’s than those who don’t supplement.

The study involved more than 12,000 cognitively healthy older adults. Researchers gathered information about the participants' vitamin D supplementation practices and whether they developed Alzheimer’s over 10 years.

They found that participants who took any form of supplemental vitamin D (D2, D3, or D3 with calcium) had a 40% lower risk of developing Alzheimer’s than non-supplementers. This effect was more robust in women, those with normal cognition, and people without the APOE4 gene (a risk factor for Alzheimer’s).

These findings suggest that supplemental vitamin D protects against Alzheimer’s. However, this was an observational study, so other factors might have influenced the participants' Alzheimer’s risk. For example, those who took supplemental vitamin D had higher education than those who didn’t. Research suggests that higher educational attainment is associated with a lower risk of Alzheimer’s.

Nevertheless, vitamin D is essential for human health, and most people living in the U.S. have low vitamin D levels, potentially driving the growing number of Alzheimer’s cases. Learn more about vitamin D’s effects on the brain in this episode featuring Dr. Rhonda Patrick.