Daily Vitamin D May Reduce Alzheimer's Risk, Study Suggests

A daily dose of Vitamin D could help protect against Alzheimer's, experts discover. Researchers have uncovered a potential link between higher midlife Vitamin D levels and reduced accumulation of tau protein—a hallmark of the disease—years later. The study followed 793 participants with an average age of 39 who had no dementia at the start. Their blood Vitamin D levels were measured initially, and brain scans were conducted 16 years later to assess tau and amyloid beta proteins, both markers of Alzheimer's.

Higher Vitamin D levels were defined as above 30 nanograms per millilitre, a threshold many experts consider sufficient for overall health. Around a third of the study group had levels below this, and just 5% regularly took supplements. The findings suggest that those with higher Vitamin D in midlife had lower tau protein levels later, but no significant connection was found with amyloid beta.

Martin David Mulligan from the University of Galway called the results "promising." He emphasized that low Vitamin D could be a modifiable risk factor for dementia. "Midlife is a time where risk factor modification can have a greater impact," he said. However, the study's limitation—measuring Vitamin D only once—means long-term changes in levels were not tracked.

Vitamin D, often called the "sunshine vitamin," is unique because the body produces it through sunlight exposure. It functions more like a hormone than a traditional vitamin, influencing processes from bone health to immune response. Health experts recommend adults over 65 take 10 micrograms daily, especially those with limited sun exposure or who are housebound.

As people age, cellular damage increases, leading to inflammation and a higher risk of diseases like dementia. Scientists are exploring ways to slow this biological aging process. A separate study found that older adults taking daily multivitamins aged more slowly at a cellular level. The effect was equivalent to reducing biological age by about four months over two years.

This research, published in *Nature Medicine*, used data from the COSMOS trial, a large U.S. study on supplements. While the benefits were modest, scientists called multivitamins a "simple, accessible" tool for healthier aging. However, both studies highlight the need for more research before making definitive claims.

Public health advisories stress the importance of balanced, evidence-based approaches. For confidential support, Alzheimer's Society offers a Dementia Support Line at 0333 150 3456. Their symptoms checker can help identify early signs of dementia. Communities with limited access to sunlight or nutrients may face higher risks, underscoring the need for targeted interventions and further investigation into modifiable factors like Vitamin D levels.