In what is regarded as the first large, population-based study of its kind, a team of researchers has found a link between vitamin D consumption and the risk of developing dementia. Older people who do not get enough vitamin D could double their risk of developing the condition. Share on Pinterest Vitamin D is important for the body’s immune function, growth and repair of bones, and normal calcium and phosphorus absorption. It can be obtained from fish, milk, eggs and cheese. Dementia is a collective term used to describe the problems that people with various underlying brain disorders can have with their memory, language and thinking. Alzheimer’s disease is the best known and most common disorder under the umbrella of dementia. Alzheimer’s disease is the sixth leading cause of death in the US and is believed to currently affect 5.3 million Americans, according to the Centers for Disease Control and Prevention (CDC). It is most common in people aged over 65, in which a tenth of the population has the condition. The authors of the study, published in Neurology, state that low concentrations of vitamin D are associated with the development of Alzheimer’s disease. Worryingly, there are high rates of vitamin D deficiency in older adults – the group most at risk from developing dementia. The CDC report that one third of the US population do not get sufficient amounts of vitamin D, with 8% of the population at risk of vitamin D deficiency. Vitamin D is obtained from sun exposure and foods such as milk, eggs, cheese and fatty fish.

Vitamin D and dementia: a strong association For the study, the researchers tested 1,658 dementia-free people aged over 65 who had participated in the US population-based Cardiovascular Health Study. The vitamin D levels in their blood were tested, and they were followed up for an average of 5.6 years. During this follow-up period, 171 of the participants developed dementia and 102 participants developed Alzheimer’s disease. The researchers found the participants with low levels of vitamin D were 53% more likely to develop dementia, and those who were severely deficient were 125% more likely, when compared with participants with regular levels of vitamin D. Similarly, participants with low levels of vitamin D saw a 70% increased risk of developing Alzheimer’s disease, and those with severe deficiency had an increased risk of 120%, again when compared with participants with normal levels of the vitamin. Study author David J. Llewellyn, of the University of Exeter Medical School in the UK, was surprised by the extent of their results, saying, “we actually found that the association was twice as strong as we anticipated.” The results of the study remained the same even after adjusting for other variables – such as alcohol consumption, smoking and education – that could affect the risk of developing dementia.