India is a vast tropical country extending from 8.4º N latitude to 37.6° N latitude, with majority of its population living in areas receiving ample sunlight throughout the year. Enough sunlight is necessary for the body to synthesize Vitamin D, which is naturally present in very few foods. Hence, it is hard to believe that Vitamin D deficiency is quite common in India despite abundant sunshine. Even though Vitamin D deficiency is common worldwide, identifying a criterion for its definition remains unresolved. Exact cut-offs for “deficiency” and “insufficiency” remain controversial.

Many laboratories worldwide are now defining Vitamin D deficiency as a serum 25-hydroxy Vitamin D [25(OH)D] level (the form of Vitamin D that circulates in blood) as < 20 ng/ml (< 50 nmol/L), and Vitamin D insufficiency (mild Vitamin D deficiency) as a level < 30 ng/ml (< 75 nmol/L).  It has also been suggested that increasing serum 25(OH)D to an “optimal” level could improve a wide range of health outcomes, including better bone and dental health, fewer falls and fractures, and possible protection against cancer and autoimmune disease.

In India, however, there is no standard as of now for determining how much 25(OH)D is adequate. While some diagnostic labs follow the standard set by the US National Osteoporosis Foundation, most researchers have set their own standards. This lack of standards can lead to overestimation of the prevalence of the deficiency and irrational use of Vitamin D supplements. Moreover, there are hardly any studies in India to estimate how much Vitamin D is adequate for Indians, who receive ample sunlight, or how much Vitamin D-producing UVB rays reach the ground and whether air pollution blocks it.

If one accepts the earlier mentioned new laboratory criteria, then inadequate Vitamin D status emerges as a major epidemic, being present in 40-50% of patients in many studies from literature. Moreover, the amount of supplemental Vitamin D needed to achieve “adequate” or “optimal” Vitamin D status is well above 800 IU/day in many cases. Talking about sunlight, even exposure in the sun in as little time as 10 minutes could give enough radiation to produce about 10,000 international units of Vitamin D. Yet, after reviewing the current literature, several conclusions can be drawn.

1. First, serum 25(OH)D is not an entirely reliable indicator of Vitamin D status.
2. Second, an increase in the lower end of the reference range for serum 25(OH)D may not be appropriate for some populations and some individuals.
3. Third, the evidence supporting the benefit of pushing serum 25(OH)D to an “optimal” level is weak.
4. Fourth, the evidence supporting the long-term safety of Vitamin D in doses greater than 2,000 IU/day is weak. Of particular concern is the possibility that long-term use of high doses might promote the development of atherosclerosis or kidney stones.
5. Fifth, the physiological effects of sunlight exposure differ from those of Vitamin D supplementation. One implication of that fact is that Vitamin D supplementation may not duplicate the beneficial effects of sunlight exposure.
6. Furthermore, evidence regarding the safety of Vitamin D synthesized in the skin might not apply to orally administered Vitamin D. Although large doses of supplemental Vitamin D have been safe and effective for some patients, routine use more than 2,000 IU/day of Vitamin D for the sole purpose of achieving a target 25(OH)D level may be unwarranted.

The supplemental Vitamin D3 market is increasing over time.  The May 2014 MAT (moving annual total) value has been reported to be is Rs. 252 crores (Rs. 2520 million) and has registered 40.8% growth in comparison to May 2013 MAT value (which was Rs. 179 crores market). A primary reason for this huge rise is the increasing number of prescriptions of supplemental Vitamin D. This is due to the prevalent myth that people in India suffer from Vitamin D deficiency and also due to the increasing sales targets outlined by pharmaceutical companies, being chased by both physicians as well as drug manufacturers, and in order to position their drugs in the market. Instead of focusing on positioning these unnecessary drugs wasting truckloads of money, manufacturers can focus on the research on other important molecules from which patients can actually benefit.

In light of this evidence, All India Institute of Medical Sciences (AIIMS) recently published a study stating mass food fortification for Vitamin D deficiency is unnecessary in India. The study was published recently in the Journal of Bone Mineral Metabolism  and the authors feel that it was important to bust the myth that Vitamin D deficiency is prevalent in India. This impression has been created because most of the studies have concentrated on urban Indians living indoors or engaged in indoor work. Large areas of the country remain unmapped for prevalence of Vitamin D deficiency. Universal supplementation cannot be based on limited studies done in a few urban pockets. The study assessed the Vitamin D levels of indoor and outdoor workers to conclude that the outdoor workers were able to achieve sufficient levels of Vitamin D, similar to the levels achieved by indoor workers given supplements during an earlier study done by the same group of researchers. Study added that the deficiency was one that could be overcome by sufficient sun exposure.

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