German scientists conducted a five-year study of more than 1,600 people in Germany aged 65 and older. They found that women with the lowest blood levels of vitamin D had a far lower score on a test that measured memory, concentration and other cognitive abilities, compared to women with the highest blood levels.
The authors' conclusion: "… low levels of vitamin D may be associated with reduced cognitive functioning in the elderly."
The bottom line is that you should spend some time out in the sun every day to make sure you manufacture plenty of vitamin D (sun exposure is fine; sunburn is not.)
"Vitamin D and cognitive functioning in the elderly population in Germany." Breitling LP, Perna L, et al. Experimental Gerontology, 2012 Jan;47(1):122-7. Epub 2011 Nov 21.
Jacob Teitelbaum, M.D. is one of the world's leading integrative medical authorities on fibromyalgia and chronic fatigue. He is the lead author of four research studies on their treatments, and has published numerous health & wellness books, including the bestseller on fibromyalgia From Fatigued to Fantastic! and The Fatigue and Fibromyalgia Solution. Dr. Teitelbaum is one of the most frequently quoted fibromyalgia experts in the world and appears often as a guest on news and talk shows nationwide including Good Morning America, The Dr. Oz Show, Oprah & Friends, CNN, and Fox News Health.