Taking high doses of vitamin D supplements could offer a protective benefit against cognitive decline, particularly for older adults experiencing early signs of dementia, according to a new study from Emory University.
The research, published in the journal “Sleep Medicine,” examined 54 adults with mild cognitive impairment and sleep disturbances. Participants who received at least 5,000 IU of vitamin D daily demonstrated improved cognitive function compared to those who did not take the supplement. The study utilized the Montreal Cognitive Assessment, a screening tool for dementia risk, where participants taking 5,000 IU of vitamin D scored approximately 13% higher than the control group.
“In older adults experiencing both sleep disturbance and mild cognitive impairment, this may represent a critical window for intervention, when cognitive changes are emerging, but opportunities to support brain health may remain,” said study author Victoria Pak in a press release. The favorable cognitive effects were observed with both vitamin D2 and D3, but only when the daily dosage reached 5,000 IU or more.
Previous research has also suggested a link between low vitamin D levels and an increased risk of Alzheimer's disease and dementia. Some evidence indicates that maintaining high vitamin D levels throughout midlife may lead to fewer dementia risk factors in later years. However, the Emory study's limitations include its small sample size, making it difficult to generalize the findings to a broader population. The study also focused specifically on cognitive impairment and sleep issues, not accounting for other potential dementia indicators such as mood changes.
Vitamin D is primarily obtained through sunlight exposure, supplements, and certain foods like fatty fish, milk, and egg yolks. Despite its importance, an estimated 40% of American adults have insufficient or deficient levels of vitamin D. Beyond brain health, low vitamin D is also a risk factor for cardiovascular disease, which in turn heightens the risk for dementia.
While vitamin D supplementation may help slow cognitive decline, it is not a guaranteed preventative measure against dementia. The study authors noted that identifying accessible factors like vitamin D intake during the early stages of cognitive decline is crucial, especially with projections indicating a doubling of dementia cases by 2060 due to an aging population and other health factors.
Complementary lifestyle choices that may help reduce dementia risk include managing blood pressure and diabetes, regular exercise, maintaining social connections, a diet rich in whole grains, fruits, and vegetables, engaging in mentally stimulating activities, ensuring adequate sleep, and addressing hearing loss. Consulting a healthcare provider before starting any new supplement regimen, including vitamin D, is important, as supplements can interact with certain medications and may not be suitable for everyone.