Are low levels of Vitamin D associated with the development of dementia?

A research study from the University of Exeter, published in the Journal of Neurology found a strong relationship between the development of Alzheimer’s disease and other forms of dementia and low levels of Vitamin D. The study included over 1600 adults over 65 years old who participated in the U.S. Cardiovascular Health Study. Participants of the study had their blood samples collected at the start of the study and mental status was assessed nearly 6 years later. Adults who had moderate Vitamin D deficiency had a 53% increased risk of developing dementia of any kind and 69% risk of develop Alzheimer’s disease. For those who were found to be severely Vitamin D deficient, there was a 125% risk of developing dementia and 122% increased risk of developing Alzheimer’s disease.

For the purposes of this study, a Vitamin D level of less than 50 nmol/L appeared to be threshold at which the risk of Alzheimer’s disease and other forms of dementia increased. This study is the largest yet to identify this association.

What remains unknown is the true cause and effect of this. It is unknown if increasing levels of Vitamin D would actually lower the risk of Alzheimer’s or dementia. More than 5 million people in the U.S. are affected by Alzheimer’s disease as the most common form of dementia. Worldwide, it estimated than over 44 million suffer from some form of dementia and this number is expected to grow with an aging population.

The authors of the study concluded that further studies are needed to establish whether the consumption of certain foods or taking a Vitamin D supplement can delay or prevent the onset of Alzheimer’s and dementia. The main source of Vitamin D for many is exposure to sunlight. However, the aging process results in skin that is less efficient at converting sunlight in a usable form of Vitamin D. Therefore, further supplementation through diet may be necessary to achieve adequate levels.

A group from the University of Guelph in Ontario, Canada has recently developed a mobile tracking application (‘App’) to help calculate intake of Vitamin D from food sources and exposure to sunlight. Using this newer technology as a tool may help users identify if they are below levels of adequate Vitamin D intake and lead to healthier behaviors.

References: Littlejohns TJ, Henley WE, Lang IA, Annweiler C, Beauchet O, Chaves PH, Fried L, Kestenbaum BR, Kuller LH, Langa KM, Lopez OL, Kos K, Soni M, Llewellyn DJ. Vitamin D and the risk of dementia and Alzheimer disease. Neurology. 2014 Sep 2; 83(10):920-8.

Goodman S, Morrongiello B, Simpson JR, Meckling K. Vitamin D intake among young Canadian adults: validation of a mobile Vitamin D Calculator App. Journal of Nutrition Education and Behavior. 2015; 47(3): 242.