Inadequate levels of vitamin D may have a negative effect on the brain, according to a new study. Researchers at the University of Kentucky have determined that low levels of the “sunshine vitamin” may lead to so-called free radical damage to the brain as well as several other organs. The findings may lead to new health guidelines for individuals at risk of Alzheimer’s disease and other types of cognitive decline.

The study, published in the journal Free Radical Biology and Medicine, examined the relationship between vitamin D and nitrosative stress — a type of damage caused by stray molecules known as free radicals. To do this, the researchers fed middle-aged rats a diet low in vitamin D for several months. The subjects also underwent regular tests designed to assess learning and memory function.

At the end of the trial period, the treatment group showed signs of significant cognitive decline. According to lead author Allan Butterfield, this provides strong evidence that low vitamin D levels promote this type of free radical damage. "Given that vitamin D deficiency is especially widespread among the elderly, we investigated how, during aging from middle age to old age, low vitamin D affected the oxidative status of the brain,” he said, speaking to Medical News Today. “Adequate vitamin D serum levels are necessary to prevent free radical damage in brain and subsequent deleterious consequences."

To replenish vitamin D levels, the team recommends that everyone allow themselves at least 10 to 15 minutes of sunlight every day. The vitamin can also be derived from a number of different food and beverages, such as eggs, oily fish, and milk.

Butterfield and his team’s paper dovetails with a series of previous studies underscoring the importance of adequate vitamin D intake. Earlier this month, researchers at Johns Hopkins University School of Medicine showed that vitamin D can block debilitating symptoms associated with multiple sclerosis (MS). Both studies recommend that elderly people and other at-risk demographics talk to their physicians about maintaining adequate levels of the vitamin.

To learn more about increased vitamin D intake and other healthy ways to combat free radical damage, visit the Mayo Clinic’s guide to antioxidants.

Source: Keeneya JTR, Förstera S, Sultanaa R, Brewerb LD et al. Dietary vitamin D deficiency in rats from middle to old age leads to elevated tyrosine nitration and proteomics changes in levels of key proteins in brain: Implications for low vitamin D-dependent age-related cognitive decline. Free Radical Biology and Medicine. 2013.