Vitamin D deficiency may be linked to an increased risk of dementia, study says
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A recent study has found that deficiency in vitamin D may be linked to some conditions and diseases.
Researchers at the University of South Australia performed what they call a “world-first” study in which they found a low level of vitamin D is associated with an increased risk of dementia and stroke.
“Vitamin D is a hormone precursor that is increasingly recognized for widespread effects, including on brain health, but until now it has been very difficult to examine what would happen if we were able to prevent vitamin D deficiency,” Elina Hyppönen, a professor and senior investigator and director of the university's Australian Centre for Precision Health, says in a press release.
The study, published in the American Journal of Clinical Nutrition, analyzed data from just over 294,000 participants from the UK Biobank, a biomedical database. It did not include participants that had a family history of dementia.
Researchers found that participants with vitamin D levels lower than 25 nanomoles per litre (nmol/L) were predicted to be 54 per cent more prone to dementia compared to participants with vitamin D levels of 50 nmol/L, which is considered a normal vitamin D level.
Hyppönen says in the population that was studied, up to 17 per cent of dementia cases might have been avoided had the vitamin D levels been within a normal range.
However, the authors also concluded that more research is needed to confirm the link between low levels of vitamin D and the risk of dementia.
What is dementia?
Dementia is a general term for loss of memory, language, problem-solving and other thinking abilities that is significant enough to affect a person’s daily life.
There are many different types of dementia, with the most common form being Alzheimer’s disease.
According to the Alzheimer Society of Canada, there are more than 500,000 Canadians currently living with dementia — and experts say that number will likely only increase.
“We know that the number of older adults over the age of 85-years-old are expected to triple in the next 25 years, which means the number of people living with dementia will be increasing significantly,” says Dr. Roger Wong, who is a clinical professor of geriatric medicine at the University of British Columbia.
Why is vitamin D important for our health?
Vitamin D is both a nutrient we eat — found in salmon and cod liver oil — and a hormone our bodies produce. Few foods naturally contain vitamin D, so many people need to take supplements to up their intake.
Vitamin D helps our bodies absorb and retain calcium and phosphorus, both of which are crucial for bone health. On top of that, some studies have shown that vitamin D can help reduce cancer cell growth, help control infections and reduce inflammation.
Deficiency in the vitamin is common among older adults. As people get older, their skin’s ability to synthesize vitamin D from the sun goes down.
The amount of vitamin D people need depends on their age. For older patients, the Cleveland Clinic recommends between 800 to 2000 IUs per day.
What Canadian researchers say
Wong says the study starts an important conversation about dementia, especially with Canada’s aging population.
The geriatric specialist adds that it also provides clues in terms of an association between lower levels of vitamin D in the blood with the occurrence of dementia and stroke.
However, there are limitations to the study.
“The association that you see with the low vitamin D level in this study, and the findings, are at best described as associations and not causation,” Wong explains during his interview with Yahoo Canada.
The study also focuses on a younger population, with the oldest participants being 70 years old when the study began. Wong says the risk of dementia goes up with age, with seniors over 85 years old being particularly vulnerable to the disease.
Moreover, the research also focused on a population in the United Kingdom, which has a predominantly white population compared to Canada.
“We need more studies actually in the Canadian setting, but with a diversity lens. I think that's so important,” Wong adds.
Even with these limitations, Wong says every little bit helps when it comes to learning more about dementia, and one day finding a cure.
“I don't think one can definitively say there is a causative effect of low vitamin D and dementia, because in individuals who are living with dementia, such as Alzheimer's disease, the question becomes, if you give them vitamin D, are they going to improve?” he says. “Does it have a treatment or therapeutic effect? And the answer to that question is unknown.”
When speaking about dementia prevention, Wong advises seniors and their families to take care of their overall health. It’s important to be aware of other risk factors linked to dementia, including stroke.
Steps you can do to help prevent stroke include eating a well-balanced diet, maintaining a healthy weight, quitting smoking and limiting how much alcohol you drink.
“Something as straightforward as exercise is critically important,” Wong adds. “Physical activity or exercise has been shown time and time again to be very effective in maintaining brain health and preventing stroke and therefore indirectly preventing dementia.”
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