Research Shows A Connection Between Low Vitamin D & Alzheimer's Disease Risk

Alzheimer's disease is the leading cause of dementia, accounting for 60 to 80% of all dementia cases. And the number of people living with Alzheimer's disease is expected to triple (from 50 million) in less than 30 years.

So there's an increasing interest and urgency to better understand the risk factors of the disease so that we can take a proactive approach to reduce our risk. And researchers have their eye on vitamin D levels as a potential indicator.

Researchers of a 2023 meta-analysis pooled data from six studies and almost 11,000 people to see if there was a correlation between low vitamin D levels and the likelihood of developing Alzheimer's disease (because past studies showed varying results). 

And sure enough, people with low blood levels of vitamin D [aka serum 25(OH)D]—defined as having serum levels less than 25 ng/mL—had a 59% higher risk of developing Alzheimer's disease than those who had vitamin D levels higher than that. 

This study points to a convincing correlation, but it doesn't indicate whether vitamin D levels changed during a study's follow-up period, and researchers didn't look into the factors that impact vitamin D status (like diet, sun exposure, and supplementation). 

But sufficiency isn't necessarily good enough. You should really be aiming for serum 25(OH)D levels of 50 ng/mL or higher for optimal whole-body health.

A lofty 41% of people have insufficient vitamin D3, and chances are, you may benefit from getting more of this beneficial vitamin daily. 

Some foods do naturally contain vitamin D 4(like the flesh of fatty fish) or are fortified with it (like dairy or dairy alternatives). But your choices are quite limited. 

Your body is also naturally able to synthesize vitamin D from the sun's rays, but too much sun exposure comes with its own health risks. 

A high-quality vitamin D3 supplement (the body's preferred form of the vitamin) is likely the most effective option to increase insufficient levels. Research shows you need a minimum of 2,000 to 3,000 IU of vitamin D3 every day5 to consistently achieve a 25(OH)D blood level greater than 30 ng/mL.

Vitamin D plays an important role in cognition and brain health, and having a low vitamin D status may increase your chances of cognitive decline and developing Alzheimer's disease.