Edinburgh University research suggests ‘lack of vitamin D could cause dementia’ 

A lack of vitamin D – which comes from sunshine – could raise your risk of getting dementia, according to research.

It is already known that someone’s genetics can raise their danger of developing dementia, as can smoking or being overweight.

But a new study from Edinburgh University has found a lack of sunshine could increase the risk.

People around the world with low vitamin D levels were found to have a higher risk of developing dementia, with researchers suggesting they could in future be advised to take supplements or spend more time outside to protect themselves.

The so-called ‘sunshine vitamin’ helps to clear protein build up which can cause Alzheimer’s disease, according to a study by the University of Edinburgh

The vitamin, which people get when their skin is exposed to sunlight, helps to clear the protein build-up which can cause Alzheimer’s disease.

It was found to be a potential environmental cause of dementia along with exposure to air pollution, pesticides and excessive levels of minerals such as aluminium in drinking water.

Dr Tom Russ, of the Alzheimer Scotland Dementia Research Centre at the University of Edinburgh, said: ‘Our ultimate goal is to prevent or delay the onset of dementia. Environmental risk factors are an important new area to consider here, particularly since we might be able to do something about them.’

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If research proves without doubt that vitamin D deficiency causes dementia, he added: ‘You could help people to prevent the onset of dementia through taking supplements, getting outside more or limiting air pollution.’

About a third of Alzheimer’s cases have previously been blamed on the way we live, with diabetes, smoking, high blood pressure and obesity all raising the risk. 

Another third are put down to genes, with those whose parents have dementia believed by experts to be more vulnerable.

The remaining third of risk is believed to be down to the environment we live in, with evidence strongest for vitamin D and air pollution.

Last year Edinburgh scientists reported findings that living further north might raise a person’s risk of getting dementia. 

Excessive mineral content in drinking water has also been linked to the disease by researchers

People in Scotland and Sweden were more likely to have it if they lived in the north rather than the south, suggesting being further from the equator with less sunshine affects brain health.

The latest research combines three studies of almost 1,200 people, which found a higher risk of dementia among those with lower vitamin D levels.

It is not yet clear that it is the lack of vitamin D which causes the rise in dementia, but the researchers state that it has numerous effects relating to Alzheimer’s.

The ‘sunshine’ vitamin helps to maintain the blood vessels in the brain, which cause vascular dementia when they are damaged. It is blocked and leaky blood vessels which cause memory loss, by stopping blood getting to brain cells, which then die.

Vitamin D also stimulates white blood cells called macrophages, which help clear the build-up of the rogue protein amyloid – which also causes memory loss.

Dr Rosa Sancho, head of research at Alzheimer’s Research UK, said: ‘This study indicated an association between vitamin D deficiency and increased dementia risk. 

Air pollution is one of the environmental factors that may be associated with dementia

‘While the reasons for this relationship are unclear, current government advice recommends that people consider a daily supplement of vitamin D, particularly if they are unlikely to gain enough through their diet and daily exposure to sunlight.’

The University of Edinburgh study, published in the journal BMC Geriatrics, reviews 60 previous studies for environmental causes.

It also found evidence that nitrogen oxides in the air raised dementia risk, along with carbon monoxide and even tobacco smoke in a Chinese study. 

People in city centres can display higher rates of dementia than those in the suburbs, highlighting the effect of pollution.

It found mixed evidence that minerals found in tap water may be linked to the disease, with more than 0.1mg a day of aluminium in drinking water found to triple the risk of Alzheimer’s disease in a large French study.

People exposed to pesticides, through working as farmers for example, could also be at risk.