There has been a lot of hullabaloo over Vitamin D in recent years.
People who stay outdoors all day long buy Vitamin D pills over the counter and pop them. Well-meaning elderly women prescribe it to younger ones, as if it is an elixir.
Do they all really need supplements?
Of the 37,812 people tested at Neuberg Anand Diagnostic Laboratory, Bengaluru, about 73 per cent, across age groups and gender, were found to have insufficient Vitamin D. In that, about 47 per cent had Vitamin D deficiency.Taking supplements could do good for some of these people, says Prof Shah Alam Khan, professor, department of orthopedics, All India Institute of Medical Sciences, New Delhi.
Khan, however, believes that there is another reason for Vitamin D pills becoming a popular health ritual in India. “Pharma comapanies nowadays thrust vitamin D as a panacea for all illnesses. Vitamin D, like many other such food supplements, is being marketed ferociously in the recent times. It is as if it is a drug in search of a disease,'' he says.
A child requires just 400 to 600 International Units of Vitamin D per day. The daily requirement for people above 70 years of age is 800 IU and for pregnant women is 600 IU.
Vitamin D is found in foods like fish, egg yolk, fish liver oil and in raw milk. The synthesis of Vitamin D happens in the epidermal layer of the skin, activated by ultraviolet rays of the sun.
Khan agrees that the sources of this fat soluble vitamin are limited, particularly for vegetarians and vegans. ''They may need to take Vitamin D supplements, in some cases. But they shouldn't consider these supplements as an alternative to healthy lifestyle and food habits,'' he says.
Sunlight is the best source of vitamin D. Spending time outdoors for 15-20 minutes during daytime, sans sunscreen, will enable most people to meet their vitamin D requirements. A study conducted in 2013 found that mushrooms exposed to sunlight can supply as much Vitamin D as supplements. Cheese, yogurt, soy milk and cereals also contain Vitamin D.
Vitamin D is essential for good bone health. However, deficiency of vitamin D is just one of the several factors that causes osteoporosis. ''It just has an indirect role in Osteoporosis. Deficiency of Vitamin D causes lack of calcium availability and therefore the role is indirect,'' says Khan. ''Osteoporosis is a complex disorder, mainly of two types—there is the post-menopausal variety, which affects females past the age of 45/50 years and the involutional type of Osteoporosis which affects both males and females beyond the age of 70 years. Vitamin D has a causal role in the involutional (senile) variety and has a complementary role in the post-menopausal type of osteoporosis,'' he adds.
In recent times, there has been renewed interest in the role of vitamin D in immune function, says Khan. ''Diseases like tuberculosis have been linked with patients who are deficient in the vitamin. Vitamin D has been implicated in the cause of heart disease too. However, the evidence for both of the same are deficient or flimsy,'' says Khan.