Natural Health News – Vitamin D deficiency is associated with a significantly increased risk of dementia and Alzheimer’s disease in the elderly, according to the most robust study of its kind ever conducted.
An international team, led by Dr. David Llewellyn at the University of Exeter Medical School, found that study participants who were severely deficient in vitamin D were more than twice as likely to developing dementia and Alzheimer’s disease.
The study was funded in part by the Alzheimer’s Association, and published in neurology . It looked at 1,658 adults 65 and older, who were able to walk unassisted and were free of dementia, cardiovascular disease and stroke at baseline. Participants were followed for six years to investigate who went on to develop Alzheimer’s disease and other forms of dementia.
The team studied older Americans who took part in the largest Cardiovascular Health Study . They found that adults in the study who were moderately deficient in vitamin D had a higher risk of developing dementia of any type of 53%. This risk increased to 125% in those who were very poor.
Similar results for Alzheimer’s disease, with moderately poor group 69% more likely to develop this type of dementia, jumping to an increased risk of 122% for those with severe deficiency.
The study also found evidence that there is a threshold level of vitamin D circulating in the blood stream below which the risk of developing dementia and Alzheimer’s disease increases. The team had previously hypothesized that this could be in the region of 25-50 nmol / L, and its new findings confirm that vitamin D levels above 50 nmol / L is strongly associated with good brain health.
implications for public health
Dr. Llewellyn said: “We expected to find an association between low levels of vitamin D and risk of dementia and Alzheimer’s disease, but the results were surprising – we actually found that the association was twice as strong as anticipated
dementia is one of the greatest challenges of our time, with 44 million cases worldwide – number waiting to triple by 2050 as a result of a rapidly aging population. one billion people worldwide are believed to have low levels of vitamin D and many older adults may experience ill health as a result.
previous research found that people with low levels of vitamin D are more likely to experience cognitive problems happen, but this study confirms that this results in a substantial increase in the risk of Alzheimer’s disease and dementia.
Vitamin D comes from three main sources – exposure of the skin to sunlight, foods such as oily fish and supplements. the skin of older people may be less efficient in converting sunlight into vitamin D, making them more likely to be poor and dependent on other sources. In many countries, the amount of UVB radiation in winter is too low to allow the production of vitamin D.
In general, should be the goal of getting 15 minutes of exposure to sunlight (without sunscreen) per day to help maintain vitamin D levels it topped up.
Dr. Llewellyn added: “Clinical trials are now needed to establish whether eating foods such as oily fish or take vitamin D supplements can delay or even prevent the onset of Alzheimer’s disease and dementia … our results are very encouraging, and even if a small number of people who could benefit, this would have enormous consequences for public health, given the devastating and costly nature of dementia. “
- For more information on getting enough vitamin D see Q & A: can you get enough vitamin D without sun?