Scientists have identified a direct correlation between a vitamin D deficiency among elderly people with accelerated cognitive decline, particularly with memory loss traits that are typically linked with Alzheimer's and dementia. Researchers from the UC Davis Alzheimer's Disease Center and Rutgers University found that a vitamin D insufficiency is putting the elderly at risk, with those with it have a cognitive decline at three times the rate of their peers.
Joshua Miller, professor in the Department of Pathology and Laboratory Medicine at the time when the research was conducted and now professor and chair of the Department of Nutritional Sciences at Rutgers University, said: "Independent of race or ethnicity, baseline cognitive abilities and a host of other risk factors, vitamin D insufficiency was associated with significantly faster declines in both episodic memory and executive function performance.
"This work, and that of others, suggests that there is enough evidence to recommend that people in their 60s and older discuss taking a daily vitamin D supplement with their physicians. Even if doing so proves to not be effective, there's still very low health risk to doing it."
The research, published in JAMA Neurology, looked at around 400 racially and ethnically diverse men and women in Northern California. The participants had a mean age of 76 and their cognitive ability varied between cognitively normal, had mild cognitive impairment, or dementia.
Their vitamin D status was measured at the start of the study – with 26% of participants deficient and 35% insufficient. Over the next five years, those with a vitamin D deficiency experienced cognitive decline at a rate of two to three times the rate of those with adequate vitamin D levels.
Charles DeCarli, director of the Alzheimer's Disease Center, added: "We expected to see declines in individuals with low vitamin D status. What was unexpected was how profoundly and rapidly [low vitamin D] impacts cognition.
"I don't know if replacement therapy would affect these cognitive trajectories. That needs to be researched and we are planning on doing that. This is a vitamin deficiency that could easily be treated and that has other health consequences. We need to start talking about it. And we need to start talking about it, particularly for people of colour, for whom vitamin D deficiency appears to present an even greater risk."