Vitamin D is not a vitamin but indeed a hormone. Vitamin D was discovered nearly a hundred years ago and since then, several claims have been made of its role in areas other than bone and calcium metabolism. In the 1920s, it was found that a compound in cod liver oil prevented childhood rickets, a condition associated with severe bone deformities and mobility. This substance was later named Vitamin D, since vitamins A, B, and C were already known by then.

Around the same time, it was also found that ultraviolet radiation helped in Vitamin D synthesis, leading the public at large to expose themselves to sunlight, believing that 'tan is beautiful'. Nearly three decades later, evidence accumulated for adverse effects of excessive sunlight exposure - increased incidence of melanoma and other skin cancers in such individuals.

Awareness about the prevalence of Vitamin D deficiency and the role of its supplementation needs to be emphasised among the medical fraternity and general public. The Department of Pediatrics, Bangalore, Baptist Hospital, Hebbal, and ANBAI and IAP-BPS recently held a medical education programme by Dr P Raghupathy, Prof of Pediatrics at Indira Gandhi Institute of Child Health and eminent Pediatric endocrinologist. The session was chaired by Dr Alexander Thomas, CEO of Bangalore Baptist Hospital and Dr Achamma Thomas, Senior Pediatircian, BBH.

Dr Raghupathy said, "We are all Vitamin D deficient and this is because consumption of normal food does not supply Vitamin D, unless we have milk, butter, margarine, orange juice, specifically fortified with Vitamin D, as it is practised in many developed nations."
The skin is also a poor source for us, as we actively avoid the sun. Besides, pigmentation is also an impediment in facilitating Vitamin D synthesis.

This deficiency is commonly prevalent even in countries where sunshine is normally present throughout the year. For the production of active Vitamin D, well functioning intestines, liver and kidneys are required. Bone formation, calcium and phosphorus levels are dependent on adequacy of Vitamin D. Vitamin D deficiency in infants and young children causes muscle pain, difficulty and delay in standing and walking. Adults may suffer from vague muscle aches and bone pain, and tend to have an increased risk of bone fractures. They may also sway while walking (waddling gait), and may fall frequently.

Cancer of the colon, rectum, prostate and breast are known to develop more often in those who are Vitamin D deficient. Vitamin D is known to cut off blood supply to the malignant cells, thereby killing it. Children and young adults exposed to sunlight and with sufficient level of Vitamin D are known to have considerably lower risk of developing non-Hodgkin's lymphoma. It has been noted that people living in nations at a higher latitude with reduced sunshine have increased risk of cancers involving several organs.

Osteoarthritis, hypertension and cardiovascular diseases occur more often in higher latitudes. Schizophrenia, depression are observed to be less in individuals protected by adequate Vitamin D levels during their intrauterine life. Lung function improves with normal Vitamin D levels, while deficiency is associated with wheezing.

In the elderly, Vitamin D protects them against the risk of falls and fractures. One should also remember that Vitamin D must not be used in excess as it can cause Vitamin D toxicity. Undiagnosed Vitamin D deficiency is common. Vitamin D supplementation is essential for all ages in the right doses, as none of the foods that we normally eat can provide our daily requirement of this important vitamin.