Vitamin D 'linked to hypertension'
Low levels of vitamin D can trigger high blood pressure, a study has shown.
Scientists demonstrated a direct genetic link between lacking the “sunshine” vitamin and hypertension, or high blood pressure, a major risk factor for heart attacks and stroke.
The study suggests vitamin D supplements may help some at-risk patients avoid heart and artery disease.
Vitamin D is mainly made in the skin as a reaction to sunlight but may also be obtained from foods such as oily fish, eggs and fortified breakfast cereal.
But some people are less able than others to turn “raw” vitamin D into its biologically active form.
The researchers looked for genetic markers linked to higher or lower levels of metabolised vitamin D.
They found that for every 10% increase in concentrations of the 25-hydroxyvitamin form of vitamin D (25 (OH) D), the risk of developing high blood pressure fell by 8.1%.
Lead scientist Dr Vimal Karani, from the Institute of Child Health at University College London, said: “We knew from earlier observational studies that low 25 (OH) D concentrations were likely to be associated with increases in blood pressure and hypertension, but correlation is not causality.
“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.”
The findings were presented at the annual conference of the European Society of Human Genetics in Paris, France.
Inadequate levels of vitamin D are common throughout the western world. A lack of vitamin D in childhood can lead to rickets which causes long bones to weaken and bend.
A number of other conditions may also be related to vitamin D deficiency, including mental impairment, auto-immune diseases and cancer.
Dr Karani said: “Our study strongly suggests that some cases of cardiovascular disease could be prevented through vitamin D supplements or food fortification.
“Our new data provide further support for the important non-skeletal effects of vitamin D. We now intend to continue this work by examining the causal relationship between vitamin D status and other cardiovascular disease-related outcomes.
“We believe that we still have a lot to find out about the effect of vitamin D deficiency on health, and we now know that we have the tools to do so.”
The 25 (OH) D form represents vitamin D at the half-way stage of its processing in the body. It is further converted in the kidneys to calcitriol, the powerful active form of the vitamin that acts as a hormone.
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