New study finds link between low Vitamin D levels and increased blood pressure
A new study has revealed that a deficiency of Vitamin D adversely affects blood pressure (BP). The study, undertaken by Indian-born researcher Vimal Karani in London, has proved that the less the Vitamin D the higher the BP. The vitamin deficiency, apart from affecting BP, is linked to a range of diseases from bone problems to cancer. The natural source of Vitamin D is sunlight and most Indians are deficient in this vitamin.
Vitamin D is synthesised when the sun’s UV rays fall on the skin but the high melanin pigment in the skin of Indians prevents it from absorbing this key vitamin. Some studies say every second Indian is affected; others peg it higher — at eight out of every ten Indians.
Karani’s research at the University College London conclusively proves that low Vitamin D levels can lead to increased blood pressure. Karani looked at 35 studies, covering 1.5 lakh people across Europe and North America, and found people with high concentrations of 25-hydroxyvitamin D (25(OH)D) had lower blood pressure, and therefore a reduced risk of hypertension. A prehormone — 25-hydroxyvitamin D or calcidiol — is produced in the liver when Vitamin D3 is synthesised (a blood test to determine its levels is also an indicator of Vitamin D levels).
Dr Yadu Singh, cardiologist and president, Indian Australian Association of NSW, attaches immense significance to Karani’s study.
He says Vitamin D deficiency is associated with bone diseases, autoimmune diseases, propensity to infections, diabetes mellitus, some cancers and high blood pressure (hypertension). “Though the study was done among people from Europe and North America only, it has public health implications for the whole world. It is certainly more important for Indians,” says Dr Singh.
“There is a pretty high incidence of hypertension among Indians (1 in 5). Most Indians are also likely to have low Vitamin D levels, because of the darker skin and tendency to have low exposure to sun, at least in urban areas. Should Vitamin D levels be tested among people with high BP is a question which can be decided conclusively when we have studies to suggest that Vitamin D supplementation helps in the management of high BP,” he adds.
Dr Singh feels there will be more studies soon in this area, which will give a clearer direction with regard to testing and supplementation of Vitamin D for people with hypertension. “Until we have this level of evidence, I suggest people visit their GPs at regular intervals. Vitamin D is an important vitamin, so sufficient levels of this vitamin are needed for various reasons,” says Dr Singh.