We use loads of sunscreen lotion lest we get a tan and use every method in the book to save ourselves from the harsh rays of the sun.
But if we go by a latest study at All India Institute of Medical Sciences (AIIMS), we might need to do a rethink.
“Dark skin prevents ultraviolet rays-mediated Vitamin D to be formed in the body but it does not lead to over-expression of Vitamin D receptor, a hormone that regulates Calcium levels in the body,” said Dr Ravinder Goswami, assistant professor in the department of endocrinology and metabolism at AIIMS.
Melanin blocks Vitamin D from penetrating the skin, hence dark skinned Indians get less of it in their body.
“The deficiency is prevalent in most parts of India, irrespective of age, socio-economic status or gender and causes bone disorders like rickets, osteomalacia and osteoporosis. So far, these disorders were mostly attributed to Calcium deficiency," said Dr Goswami, who won the Shanti Swarup Bhatnagar Award for his paper on the ideal dosage of Vitamin D for Indians.
A 2000 study at AIIMS had established 75 per cent of the population suffer from Vitamin D deficiency but recent research has shown our skin colour is to blame for the deficiency.
“We are studying to see what could be the best way for long term restoration of ideal Vitamin D levels and whether it is also responsible for other disorders in the brain and heart,” said Dr Goswami.
Direct exposure to sunlight for at least half-an-hour a day is essential. “At least 10 per cent of the body should be exposed to direct sunlight, without sunscreen for adequate intake of Vitamin D,” he added.
“In early stages of Vitamin D deficiency, our body adapts by increasing the parathyroid hormone in the blood, which helps in maintaining the normal Calcium levels and so the deficiency is not immediately detected. But with age advancement, this leads to bone resorption, when bone breaks down to release Calcium in the blood, and osteoporosis, which causes reduction in bone density enhancing the risks of fracture,” warned Dr Goswami.
Vitamin D and Calcium are very essential for strong bones, as the former helps in absorption of the latter. Data suggests that the general dietary Calcium intake is 307 -340mg in urban population, 263-280mg in rural population, which is less than a third of the required calcium (1,000 mg/day).
Dr Goswami said a national programme of Vitamin D fortification should be undertaken.