Researchers at the University of South Australia have uncovered a link between vitamin D deficiency and an increased risk of dementia and stroke. The study found that a decent proportion of cases of dementia may be prevented by boosting levels of the hormone.
Vitamin D plays some important roles in the body, primarily helping with the uptake of calcium and phosphorus. The majority of a person’s vitamin D intake doesn’t come from food but the Sun, as the skin produces it in response to UV light exposure.
Unfortunately, it’s thought that as many as a billion people worldwide are vitamin D deficient. Not only can that lead to weaker muscles and bones, but an increasingly long list of other conditions, such as some cancers, autoimmune diseases and opioid addiction. Studies even suggest that pregnant women who are vitamin D deficient may raise the likelihood of their child developing schizophrenia or autism later in life.
In the new study, Australian researchers have now added new illnesses to that list. The team analyzed data from 294,514 participants in the UK Biobank project, comparing vitamin D levels with incidences of dementia and stroke. They used a technique called nonlinear Mendelian randomization to examine whether variation in genes had a causal effect on the illnesses, while accounting for factors like age, sex, ethnicity, lifestyle and other health conditions.
The team found that low levels of vitamin D – defined as under 25 nmol/L, or half that considered a healthy amount – was associated with lower brain volumes as measured through neuroimaging, as well as increased risks of dementia and stroke. The genetic analyses suggested a causal link between vitamin D deficiency and dementia, with the risk of the disease 54 percent higher for patients at 25 nmol/L than those at 50 nmol/L.
“Our study is the first to examine the effect of very low levels of vitamin D on the risks of dementia and stroke, using robust genetic analyses among a large population,” said Professor Elina Hyppönen, senior investigator of the study. “In some contexts, where vitamin D deficiency is relatively common, our findings have important implications for dementia risks. Indeed, in this UK population we observed that up to 17 percent of dementia cases might have been avoided by boosting vitamin D levels to be within a normal range.”
The new study adds yet more reasons to keep your vitamin D levels up with regular, controlled sunlight exposure – or perhaps in the near future, from genetically engineered tomatoes.
The new research was published in the American Journal of Clinical Nutrition.
Source: University of South Australia
