In a groundbreaking study, Dr. Martin David Mulligan from the University of Galway and his team investigated the long-term effects of vitamin D levels on brain health by following nearly 800 participants from the Framingham Heart Study for over 15 years. Their findings revealed that individuals with higher circulating levels of vitamin D at age 30 exhibited significantly less accumulation of tau protein—a key factor in the development of Alzheimer’s disease—when retested approximately 16 years later. This association remained robust even after accounting for various factors such as age, gender, cardiovascular health, smoking, depression, and BMI.
Vitamin D deficiency in midlife may be a modifiable risk factor for preclinical dementia signs observed in neuroimaging. Image credit: Aloysio Costa Latoje.
Dementia currently ranks as a leading cause of morbidity worldwide, impacting an estimated 57 million individuals.
“Our research indicates that maintaining high vitamin D levels during midlife may safeguard against the formation of tau deposits in the brain, while insufficient vitamin D could serve as a modifiable risk factor for dementia,” stated Dr. Mulligan.
“Further validation through additional studies is essential to confirm these results.”
The study analyzed data from 793 adults (53% female, average age 39 years) who were dementia-free at the time of brain imaging.
Blood levels of 25-hydroxyvitamin D were measured between 2002 and 2005, followed by positron emission tomography (PET) scans assessing tau and amyloid deposits conducted from 2016 to 2019.
Accumulation of tau protein, particularly in regions like the entorhinal cortex and temporal lobe, is known to play a crucial role in the early onset of Alzheimer’s disease.
Researchers observed that elevated vitamin D levels correlated with reduced tau levels throughout the brain and in these vulnerable areas.
“Notably, 34% of participants exhibited low vitamin D levels, and only 5% were taking vitamin D supplements,” the researchers reported.
This study contributes to the growing body of evidence correlating vitamin D with brain health, focusing specifically on early preclinical changes rather than solely on clinical outcomes like dementia diagnosis and aging.
Scientists propose that ensuring adequate vitamin D levels in midlife may serve as a proactive strategy to mitigate neurodegenerative changes before clinical symptoms manifest.
However, it is important to note that this study does not establish a direct causal relationship between vitamin D and the prevention of tau accumulation or dementia. The researchers measured vitamin D at a single time point without tracking its changes over the years, and they did not assess whether supplementation influenced brain health.
“These promising findings suggest a significant association between increased vitamin D levels in early midlife and decreased tau load 16 years later,” Dr. Mulligan remarked.
“Midlife is a critical phase where modifying risk factors could yield substantial benefits.”
For more information, refer to the published results in the journal Neurology.
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Martin David Mulligan et al. 2026. Association of circulating vitamin D in midlife with increased tau-PET burden in adults without dementia. Neurology 2 (2): e000057; doi: 10.1212/WN9.0000000000000057
Source: www.sci.news
