Vitamin D shortage link to high blood pressure
11th June 2013 - Low levels of vitamin D could cause high blood pressure, researchers claim.
A new study says the findings could be important, as many people in the western world have a shortage of vitamin D.
Vitamin D is essential for strong bones because it helps the body absorb calcium from the diet.
Traditionally, vitamin D deficiency has been associated with rickets, a disease in which the bone tissue doesn't properly mineralise, leading to soft bones and skeletal deformities. However, research is revealing that vitamin D has a role to play in protecting against other health problems.
Vitamin D shortage
The Department of Health says a signiﬁcant proportion of people in the UK have low vitamin D levels. This has resulted in a rising number of cases of rickets in children and osteomalacia in adults.
Vitamin D deficiency can occur for a number of reasons, particularly for those who follow a strict vegan or vegetarian diet, because many of the food sources of vitamin D are in animal-products such as fish oils, eggs, cheese and beef liver. As the body makes vitamin D when exposed to sunlight, living in northern latitudes, spending long periods indoors, having dark skin or wearing long robes or head coverings, can inhibit vitamin D production.
Vimal Karani Santhanakrishnan, a research associate in genetic epidemiology at University College London, will update the European Society of Human Genetics today about his findings which involve sifting data from 35 studies involving over 155,000 individuals in Europe and North America.
Heart disease and stroke
The researchers found that people with higher levels of a prehormone (25-hydroxyvitamin D) had lower blood pressure and were therefore less likely to develop heart disease, stroke and other health problems.
The results show that for every 10% increase in concentrations of 25-hydroxyvitamin D in the blood, there was a 8.1% decrease in the risk of developing high blood pressure.
The researchers say that observational studies have already shown a link between vitamin D and blood pressure, but a large-scale genetic study was necessary in order to prove cause and effect.
"Even with the likely presence of unobserved confounding factors," says Vimal Karani Santhanakrishnan in a statement, "the approach we followed, known as Mendelian randomisation, allows us to draw conclusions about causality because the genetic influence on disease is not affected by confounding.
"To put it in simple terms, by using this approach we can determine the cause and effect and be pretty sure that we’ve come to the right conclusion on the subject."
He adds: "Our study strongly suggests that some cases of cardiovascular disease could be prevented through vitamin D supplements or food fortification."
Doireann Maddock, senior cardiac nurse at the British Heart Foundation, comments in a statement: "At the moment, there’s not enough evidence to recommend that people should increase vitamin D levels to reduce their blood pressure and risk of heart disease. However, if future research does prove vitamin D is effective in this way, it has the potential to benefit a large number of people.
"In the meantime, there are other ways to tackle high blood pressure such as being physically active, maintaining a healthy weight and cutting down on salt in your diet."