Researchers investigated the relationship between vitamin D supplementation and dementia among 12,388 participants aged on average 71 who were dementia free at the start of the study; 37% supplemented with Vitamin D during that period.
Researchers discovered that supplementing with vitamin D was linked with living longer without dementia, with 40% fewer cases found among those who took vitamin D supplements.
From among all participants, 2,696 individuals developed dementia over 10 years; 75% did not receive any vitamin D exposure at any visit prior to being diagnosed and 25% had baseline vitamin D exposure.
Vitamin D’s effects on the brain have long been documented, and may play a part in mitigating dementia risk. Unfortunately, research on its benefits for dementia prevention have been mixed; this study sheds new light on who might benefit most from taking vitamin D supplements early before signs of cognitive decline surfaced. Researchers found evidence supporting their conclusion.
Vitamin D was effective across all individuals, with significantly greater results being seen among females than in males. Furthermore, individuals reporting normal cognition had greater effects than those reporting signs of mild cognitive impairment which have been associated with an increased dementia risk.
Vitamin D effects were significantly greater among individuals not carrying the APOEe4 gene, which has been proven to increase Alzheimer’s risk, than among non-carriers of this gene. Researchers speculate that individuals carrying this APOEe4 gene absorb vitamin D more efficiently through their intestinal tract which could diminish its benefits; no blood levels were measured at that time to test this theory further.
Studies have established a correlation between low vitamin D levels and an increased risk of dementia and amyloid clearance – one hallmark of Alzheimer’s disease – and vitamin D being present. Amyloid accumulation occurs with Alzheimer’s, while tau accumulation contributes to dementia as well. Research suggests vitamin D could protect against this protein build-up by protecting brain from it being exposed directly or through indirect channels such as brain imaging.
