A vitamin D deficiency can increase the risk of cardiovascular disease by 35%. This risk is particularly high in Northern Europe, which has relatively few sunlight hours. EURACTIV France reports.
The link between low levels of vitamin D and an increased risk of cardiovascular disease has been established for several years. But until recently, the importance of this link was unknown.
Thanks to a recent study, Dr Brent Muhlestein and a team of researchers at the Intermountain Medical Centre Heart Institute in Salt Lake City have been able to determine the critical threshold.
According to their results, a vitamin D level of less than 15 nanogrammes per millilitre (ng/ml) of blood increases the risk of cardiovascular disease by 35%. “Although vitamin D levels above 30 ng/ml were traditionally considered to be normal, more recently, some researchers have proposed that anything above 15 ng/ml was a safe level. But the numbers hadn’t been backed up with research until now,” said Dr Muhlestein.
For three years, the Dr Muhlestein and his team analysed the medical files of 230,000 people, tracking cardiovascular incidents and deaths. The results showed that people with vitamin D levels under 15 ng/ml were 35% more likely to suffer from cardiovascular incidents.
“Even if any level above 15 is safe, one out of ten people still have vitamin D levels lower than that. This equates to a very large percentage of our population,” the specialist said. “This study sheds new light and direction on which patients might best benefit from taking vitamin D supplements.”
The results of the study were presented at the annual conference of the American Heart Association in Florida, and will be published soon. But Dr Muhlestein’s work is not over. He is already thinking of further tests he could run.
“As we continue to study vitamin D and the heart, we hope to ultimately gain enough information so we can inform all patients specifically what they should do to reduce their cardiac risk as much as possible,” he said.
Consequences of vitamin D deficiency
Vitamin D deficiency can have various consequences, including brittle bones, muscular pain, chronic fatigue and cramps. As this vitamin acts on the thyroid and other parts of the endocrine system, its effects can be similar to those of hormones.
As well as increasing the likelihood of cardiovascular incidents, a lack of vitamin D can also hamper the recovery of stroke survivors.
The body naturally produces vitamin D when the skin is exposed to UV light. As such, vitamin D levels are directly influenced by the climate. Northern Europe has fairly high rates of vitamin D deficiency.
Health specialists recommend walking outside for at least 45 minutes, twice a week, in order to expose the body to the natural light it needs to function normally. While it is important to avoid too much UV exposure, it is just as harmful to deprive oneself completely of natural light by staying indoors or by completely covering the skin with sunblock.
Vitamin D in food
Vitamin D is also found in certain foods, like fish (notably in cod liver oil, which is often given to children to protect them from rickets, also linked to vitamin D deficiency), egg yolks and certain dairy or cereal products.
A range of factors, like digestive trouble, lack of exposure to the sun or air pollution can also lead to deficiencies in vitamin D. “The best way to determine one’s vitamin D level is by getting a blood test,” Dr Muhlestein said.
While a vitamin D deficiency should not be taken lightly, it can easily be corrected with dietary supplements.