Thursday Aug 7, 2014 (foodconsumer.org) -- In older people, vitamin D deficiency may double the risk of developing dementia and Alzheimer's disease, a study published in the August 6, 2014, online issue of Neurology® suggests.

David J. Llewellyn, PhD, of the University of Exeter Medical School in the United Kingdom and colleagues conducted the study and confirmed the previously found association between serum vitamin D and risk of dementia and Alzheimer’s disease.

For the study, 1,658 people older than 65 years who were dementia-free at baseline were followed for an average of six years, and serum vitamin D was measured for each participant at baseline and the end of the follow-up.  During the follow-up, 171 participants developed dementia and 102 were diagnosed with Alzheimer's disease.

Those with low levels of serum vitamin D were 53% more likely to be diagnosed with dementia and those with severe vitamin D deficiency were 125% more likely to develop the disease, compared to those with normal vitamin D levels.

Similarly, participants with low levels of vitamin D were 70% more likely to develop Alzheimer’s disease and those with severe vitamin D deficiency were 120% more likely to be diagnosed with Alzheimer's disease, compared to those with normal vitamin D.

The associations remained strong after adjustment for other risk factors that could affect the risk of dementia including education, smoking and alcohol drinking.

One can increase his serum vitamin D by taking vitamin D supplements like D-drops; eating cold water fatty fish like salmon, tuna or mackerel, eggs, cheese, and muschroom or exposing himself to the sun.  Mushroom is also a source of vitamin D. (David Liu)