Vitamin D deficiency may harm brain function

February 10, 2009

If you have a low level of vitamin D you may have an increased risk of suffering with cognitive impairment if you are elderly, according to findings from the nationally representative, population-based Health Survey for England 2000. To date there has been largely theoretical support for the role of vitamin D in maintaining brain function in old age, lacking hard clinical data the researchers note.  

Dr. David J. Llewellyn and his associates at the University of Cambridge studied 1766 adults, aged 65 or older, from whom blood samples were obtained to measure circulating vitamin D levels. Cognitive function was measured using the Abbreviated Mental Test, which includes 10 questions to assess attention, orientation in time and space, and memory. Based on scores of 70 percent or less, 212 subjects (12 percent) were cognitively impaired. The researchers found a significant association between lower levels of vitamin D and cognitive impairment. In fact older adults with the lowest levels of vitamin D were more than twice as likely to be cognitively impaired as those with the highest levels. The study is published in the February 2009 issue of the Journal of Geriatric Psychology and Neurology  

Study links gene variant and vitamin D to MS risk

A certain genetic variant combined with a vitamin D deficiency when young may increase a person's chances of developing multiple sclerosis later in life, British researchers from Oxford University said on Thursday. The finding suggests that giving vitamin D supplements to pregnant women and young children could reduce the risk of getting the disease. According to the scientists “There is accumulating evidence that it (Vitamin D) can reduce the risk of developing cancer and offer protection from other autoimmune diseases.” George Ebers, a researcher at the University of Oxford who worked on the study said in a state “We have known for a long time that genes and environment determine multiple sclerosis risk.” “Here we show that the main environmental risk candidate—vitamin D—and the main gene region are directly linked and interact.”

Multiple sclerosis is a disease of the nervous system caused by damage to the myelin sheath that protects nerve cells. It can cause symptoms ranging from vague tingling to blindness and paralysis. The researchers found that proteins activated by vitamin D bind to a particular DNA sequence lying next to the DRB1 variant, which in effect switches the gene on. Too little vitamin D may cause the gene to malfunction, they said.  

This means for people who carry the variant, a vitamin D deficiency during early life might impair the body's ability to delete T-cells which go on to attack the body and lead to a loss of myelin on the nerve fibers, the researchers said. The scientists reported their results in the journal PLoS Genetics.