A study published in the journal
Neurology found that older people who have a severe vitamin D deficiency have an increased risk of developing dementia. Dementia is defined as a group of related symptoms associated with ongoing problems of memory loss, problem solving, language, understanding, and judgement.
An international team of researchers, led by Dr. David Llewellyn at the University of Exeter Medical School in the UK, followed 1,650 Americans over the age of 65 for approximately six years. Research collaborators included experts from Angers University Hospital, Florida International University, Columbia University, the University of Washington, the University of Pittsburgh, and the University of Michigan.
This study is the largest of its kind so far and the results showed a higher correlation than the researchers expected.
They found 1,169 people with good levels of vitamin D had a 1 in 10 chance of developing dementia and Alzheimer's disease (AD). However, 70 study participants who were severely deficient in vitamin D were more than twice as likely to develop dementia and AD than people with sufficient levels in their blood.
Although experts say it is still too early to recommend that older people should take vitamin D supplements as a preventative treatment for dementia and Alzheimer's, it is an area that they say requires further research. It is not understood what the role of vitamin D, a vitamin that comes from foods such as oily fish and skin exposure to sunlight, as well as supplements, has in dementia prevention, but it may prove in the long run to help in treating people with dementia.
Vitamin D also is important in keeping our bones healthy, because it is involved in the absorption of essential minerals such as calcium, iron, and magnesium. Low levels of vitamin D are common in older people and can cause skeletal disorders such as
Low vitamin D levels also have been linked to other conditions including cancer, diabetes, and cardiovascular disease.
"Vitamin D and the risk of dementia and Alzheimer disease." Thomas J. Littlejohns, William E. Henley, Iain A. Lang, Cedric Annweiler, Olivier Beauchet, Paulo H.M. Chaves, Linda Fried, Bryan R. Kestenbaum, Lewis H. Kuller, Kenneth M. Langa, Oscar L. Lopez, Katarina Kos, Maya Soni, and David J. Llewellyn. Neurology. 10.1212/WNL.0000000000000755; 6 Aug.