Risk of developing Alzheimer's doubles with lack of vitamin D
A SEVERE lack of vitamin D can double the risk of Alzheimer's in older people, a study has found.
Even a moderate deficiency was found to increase the chances of developing the disease by 69pc.
Scientists were surprised by the dramatic findings, which suggest that upping vitamin D intake might delay or prevent Alzheimer's. But more research has to be done before experts can know if there is a causal link between levels of the vitamin and dementia risk.
The study looked at 1,658 American adults aged 65 and over who were free from dementia, heart disease and stroke at the outset.
Lead researcher Dr David Llewellyn, from the University of Exeter, said: "We expected to find an association between low vitamin D levels and the risk of dementia and Alzheimer's disease, but the results were surprising - we actually found that the association was twice as strong as we anticipated.
"Clinical trials are now needed to establish whether eating foods such as oily fish or taking vitamin D supplements can delay or even prevent the onset of Alzheimer's disease and dementia.
"That said, our findings are very encouraging, and even if a small number of people could benefit, this would have enormous public health implications given the devastating and costly nature of dementia."
The research showed that over an average six years, study participants who were moderately deficient in vitamin D had a 53pc increased risk of developing any kind of dementia. For those who were severely deficient, the risk increased to 125pc.
Similar striking results were seen for Alzheimer's, the most common form of dementia. The chances of people lacking in vitamin D developing the disease were raised by 69pc to 122pc depending on how deficient they were. Vitamin D can be obtained from sunlight and foods such as oily fish.
Sunshine is the most important source, but older people's skin is less efficient at harnessing ultra violet light to manufacture the vitamin. In addition, winter sun in many northern countries is too weak to generate adequate levels of vitamin D.