If there’s one vitamin that’s taken on new importance in the last few months, it’s vitamin D. Not only has it been shown that Americans don’t get enough of this vitamin, but vitamin D appears to play a pivotal role in the prevention of a variety of diseases ranging from osteoporosis to cancer. A new study now suggests that low levels of vitamin D may even reduce brain function in older people.

This study which will be published in the Journal of Geriatric Psychology and Neurology looked at 1,766 older people. After assessing their level of cognitive function, they measured blood levels of vitamin D. It was found that the older people with lower cognitive function had low levels of vitamin D in their bloodstream, while those with normal brain function had higher levels. In fact, those subjects with the lowest levels of vitamin D were four times more likely to suffer from brain impairment compared to those with the highest levels.

Could low levels of vitamin D play a role in dementia such as Alzheimer’s? Although this study doesn’t prove cause and effect, other studies have shown that vitamin D is important for normal brain development and function. The elderly population is at particularly high risk for vitamin D deficiency since they’re not exposed to as much sunlight and have a difficult time absorbing vitamin D through the skin. Low vitamin D levels have also been associated with depression in the elderly in some studies.

How much vitamin D do older people need on a daily basis? Although the minimum daily requirements for younger adults is between 200 and 400 mg. per day, the minimum requirements for the elderly population is 600 mg. per day. Many elderly patients, particularly those living in nursing homes, are unlikely to get those amounts with limited exposure to the sun. Plus, many experts believe the minimum requirements need to be higher with so many studies correlating low levels of vitamin D with an increased risk of chronic diseases.

Unfortunately, it’s difficult to get the minimum vitamin D requirements through diet alone unless vitamin D fortified foods such as milk or fatty fish are eaten several times per week. Plus, many older people don’t eat dairy foods due to lactose intolerance. With absorption of vitamin D derived from sunlight being less effective in the elderly, even outdoor exposure to sunlight may not be sufficient. Although vitamin D supplementation is an option, it’s unclear as to whether supplements provide the same benefits as vitamin D derived from food sources.

Hopefully, future studies will clarify whether vitamin D supplementation can help older people with low levels of vitamin D, particularly those who have reduced brain function due to dementia.