The common saying – “Make hay while the sun shines” is now applicable for Vitamin D also. Vit.D is an essential nutrient which performs a wide variety of vital functions in our body. Historically (I think from the time it was discovered that human skin can make Vit.D from sun rays), it has been believed that Indians have been able to synthesize adequate amounts of Vit.D but recent researches have proved this to be a disbelief. Ideally, thirty minutes of exposure of the skin over the arms and face to sunlight, without the application of sunscreen, preferably between 10 am to 2 pm (as maximum ultraviolet B rays are transmitted during this time) daily is adequate to avoid Vit. D deficiency.
India, located between 8.4 and 37.61 N latitude, is a vast tropical and warm country. Most of the Indian regions receive ample amount of sunlight throughout the year. Also being a agricultural and a rural country, most of the people spend time outdoors in the sun, so the time exposed to the sunlight is quite high. Earlier, Vit.D deficiency was considered to be disease of west, since the amount of exposure to sunlight among the western countries is very less. Surprisingly, recent researches have shown that there has been an increase in the incidence of Vit.D deficiency among Indians as well.
There may be various reasons for us developing this deficiency in spite of the widespread availability of sunlight in our country.:
- Darker skin pigmentation and the changes which have accompanied India’s modernization, including increased hours spent working indoors and pollution, limit sun exposure for many.
- Changing food fads and food habits contribute to low dietary calcium and Vit. D intake;
- High fibre diet containing phosphorus and phytates which can deplete Vit. D stores and increase calcium requirement;
- Genetic factors like having increased 25(OH)D-24-hydroxylase which degrades 25(OH)D to inactive metabolites;
- It has been shown that increment in serum 25(OH)D in response to treatment depends on the heritability of Vit. D binding protein;
- Increased pollution may also hamper the synthesis of Vit. D in the skin;
- Repeated, unspaced and unplanned pregnancies in already deficient patients may aggravate Vit. D deficiency in both the mother and the foetus.
However, in our scenario, our dietary habits are also to be blamed. Predominantly vegetarian, we do not have much choice as far as Vit.D is concerned; the vitamin is primarily present in non-vegetarian foods. Also till date, no focus has been shifted by the policy makers regarding the fortification of common foods with Vit.D.
Earlier Vit.D deficiency was only thought to be present in children of lower socioeconomic status but now the picture seems to be changing. The nutrient deficiency is now being commonly found in otherwise healthy children and adults. Deficiency of Vit.D at such a small age may hamper appropriate growth and development since childhood resulting in a clinical condition termed as rickets whereas in adults it may lead to an early onset of osteoporosis. However, the vitamin now has been shown to play a variety of roles ranging from an antioxidant to that being a anti-cancer nutrient.
It's been a high time now to open our eyes to a problem which was probably long standing but we recognized it quite late. According to a estimate by WHO, approximately one billion people in world have Vit.D deficiency.
Until fairly recently, Vit. D deficiency in children has been observed in essentially every country in the world. It affects a large proportion of population, irrespective of age and sex. The reason for delay in recognition is perhaps Vit. D is the most underrated nutrient in the world of nutrition probably because it’s “free”. But the truth is, unawareness as most people don’t know the real story of Vit. D and health.
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