It has also been linked to an increased risk of infectious diseases, cognitive decline (impairment in memory and thinking skills), autoimmune disease, heart disease, asthma, mood disorders, diabetes and cancer1 Most often, vitamin D is referred to as vitamin D3 (vitamin D2 is found in plant sources). We have sufficient evidence to indicate that nearly 90% of our body’s vitamin D requirement is met by casual, daily exposure to the sun.
For a country that receives ample sunlight, it is surprising to learn that above 70% of our population suffers from a vitamin D deficiency. Some of the reasons for this could be:
The role of melanin: People with darker skin have a higher concentration of melanin, which protects them from the sun’s harmful radiation. However, higher levels of melanin also act as a natural sunblock. This means that dark skinned people require more sun exposure to produce the same amount of vitamin D as those who are fair skinned.
Cultural blocks: Most Indians tend to be conscious of their skin tone and try their best to shun exposure to sunlight to avoid ‘becoming dark’. This cultural obsession with fair skin has a greater negative impact on our vitamin D levels than we realize. Our reluctance to any form of healthy sun exposure interferes with the body’s natural vitamin D production. Another consideration is our traditional dressing styles, which leave little bare skin that can be exposed to sunlight.
Sun exposure has its own problems: Experts say that 5 to 30 minutes of sun exposure to your unprotected face, arms, legs or back between 11 a.m. and 2 p.m. twice a week2 is enough for your body to produce all the vitamin D it needs. However, this is the time most people spend indoors at school, college or in office, and are unable to get the daily sun exposure they need.
Vegetarians at a higher risk: Although food is not a major source of vitamin D, your body does meet 10% of its vitamin D requirements from food such as fortified dairy products, liver, eggs, fish and fish oil. Since most of these are animal sources, vegetarians are at a higher risk of being deficient in vitamin D.
The link between sun exposure and skin cancer: Awareness of this link is growing and people have increased their use of sunscreen as protection. This interferes with the production of vitamin D. Acknowledging the growing problem of vitamin D deficiency in India, the Indian Council of Medical Research (ICMR) recommends regular outdoor physical activity with sufficient sun exposure to achieve adequate vitamin D levels. But considering the scale of the problem in India, much more needs to be done. A good start would be to develop educational programs that increase public awareness about vitamin D deficiency, its causes, consequences and treatment.
Patients must be made aware that supplementation, when teamed with adequate sun exposure, is sometimes all you need to reverse the deficiency. Perhaps we should also consider making regular physical activity (about half an hour a day) in the sun a compulsory part of school curricula in India.