Recent studies have rechristened Vitamin D from a mere ‘sunshine’ vitamin to a hormone with significant bearing on bones, heart, kidneys, among other organs. Efforts are now being made to understand the extent of its deficiency in the population and fight it.

Some experts believe Vitamin D deficiency is a pan–Indian phenomenon affecting people from all age–groups and sections of society, reasons for which range from lifestyle, atmospheric pollution, skin pigmentation, clothing to duration and time of exposure to sunlight daily. Endocrinologist Dr Sudhindra Kulkarni, who consults with Fortis Hospital, Mulund, said Vitamin D has been proved to play the role of regulators of cell growth. "Almost all tissues and cells in the body have receptors for it and need it, " he said.

Dr Vipla Puri, consultant (radioimmunoassay), department of Lab-Medicine at PD Hinduja Hospital, said there is epidemiologic evidence now to show Vitamin D is required for more than strong bones. "It plays a role in preventing chronic diseases involving the immune and cardiovascular system later in life, " she said. "More recently it has become a general health indicator because of its associations with major conditions like cancer. Doctors too are becoming more aware and asking for this test, " she said.

Head of the orthopaedic department at Parel’s KEM Hospital Dr Pradeep Bhonsale said Vitamin D deficiency in adults was astonishingly high and more cases are coming to fore given increased awareness. "Over 50% of patients we treat in our hospital have this deficiency. This can also shunt a child’s growth and give rise to bone deformities, " he said. He added Vitamin D deficiency was responsible for unexplained pain in the back and joint pain in children as well as adults.

While global studies have established the importance of Vitamin D as a health parameter, there is little consensus in India on how much is too much or too little for an individual. Pediatrician Dr Deepak Ugra said concentrated Vitamin D supplements provide much less than the requirement of 400 IU/ day. "Calcium tonics available in the market have only about 100ml of Vitamin D components, " he said. The American Academy of Pediatrics recently updated its Vitamin D guidelines, recommending infants children and teens should take atleast 400 IU per day in supplement form.

Kulkarni said the time of exposure to sunlight is also a subject of debate. "Some studies say 20 minutes is fine while others say it has to be over 45 minutes. On the other hand, exposure to too much sunlight has also been linked to skin cancer so one has to exercise caution, " he said.