New Study Finds Vitamin D Offers 'Triple Protection' Against Memory Loss

Researchers say vitamin D deficiency is linked to faster cognitive decline in older adults.

Apr. 13, 2026 at 9:52am

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A translucent X-ray image showing the intricate structures of the human brain, with glowing neural pathways and regions highlighted in shades of blue and purple against a dark background, conveying the complex effects of vitamin D on brain health.An X-ray view of the inner workings of the brain reveals the profound impact that vitamin D deficiency can have on cognitive function and memory.Davis Today

A new study has found that older adults with low vitamin D levels experience memory decline two to three times faster than those with healthy levels. The study tracked nearly 400 older adults and discovered that 60% had low vitamin D, with 35% having insufficient levels and 25% being severely deficient. Researchers say vitamin D deficiency is associated with significantly faster declines in both episodic memory and executive function, independent of other risk factors.

Why it matters

Vitamin D deficiency is a common but underappreciated health issue, especially among older adults and people of color. This study highlights the critical role vitamin D plays in brain health and cognitive function as we age. Addressing this deficiency could be an easy and low-risk way to help prevent or slow memory loss and cognitive decline.

The details

The study, led by researchers at the University of California, Davis, found that vitamin D insufficiency was linked to accelerated memory and cognitive decline, even after accounting for factors like race, ethnicity, baseline cognitive abilities, and other health conditions. The researchers say the findings suggest people over 60 should discuss taking a daily vitamin D supplement with their doctors, as the potential benefits outweigh the very low health risks.

  • The study was published on April 13, 2026.

The players

Joshua Miller

Professor and one of the study's authors.

Charles DeCarli

First author of the study and director of the Alzheimer's Disease Center at UC Davis.

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What they’re saying

“Independent of race or ethnicity, baseline cognitive abilities and a host of other risk factors, vitamin D insufficiency was associated with significantly faster declines in both episodic memory and executive function performance.”

— Joshua Miller, Professor

“We expected to see declines in individuals with low vitamin D status.What was unexpected was how profoundly and rapidly [low vitamin D] impacts cognition.”

— Charles DeCarli, Director, Alzheimer's Disease Center at UC Davis

What’s next

The researchers say they are planning further studies to determine if vitamin D replacement therapy could help reverse or slow the cognitive decline associated with deficiency.

The takeaway

This study underscores the importance of addressing vitamin D deficiency, which is a common but often overlooked health issue, especially among older adults and certain populations. Ensuring adequate vitamin D levels could be a simple and low-risk way to help protect brain health and memory as we age.