From our childhood, we are told that the best source of Vitamin D is sunlight. However, what happens if the sunlight is not enough to give our bodies the much-needed requirement of Vitamin D? This is a problem many Indians are struggling with.
According to Dr Monika Sharma, Senior Consultant- Endocrinology, Aakash Healthcare, “The winter sun in India creates a deceptive sense of security. People assume that daily sunlight is enough to maintain vitamin D levels, but the seasonal decline in UVB strength makes that almost impossible.”
During winter, the sun is lower in the sky, and the atmosphere blocks a major portion of UVB rays. “Even if you spend long hours outdoors, your skin is not getting the UVB exposure it needs to produce adequate vitamin D,” she explains.
Darker skin requires more sun exposure
Melanin, the pigment which gives skin its colour, also reduces vitamin D production. “People with darker skin naturally need longer exposure to generate the same amount of vitamin D as lighter skin,” says Dr Sharma. “This becomes especially difficult during winter when UVB rays are already weak.”
Urban lifestyles make sunlight exposure harder
Urban living further widens the gap. “Most people spend their day indoors, commuting in covered vehicles, or in shaded spaces. Their lifestyle simply doesn’t allow meaningful sunlight exposure,” Dr Sharma notes.Air pollution plays a major role, too. “Pollution scatters and absorbs UVB radiation, so even bright daylight in cities doesn’t translate into effective vitamin D production,” she adds.
Cultural habits and clothing limit skin exposure
Winter clothing compounds the issue. “In colder months, people cover most of their body, reducing the surface area of skin available for vitamin D synthesis,” Dr Sharma says. “Sunlight needs exposed skin to work, not just presence outdoors.”
Diet doesn’t fill the nutritional gap
Food sources don't help much in India. “Indian diets are traditionally low in natural vitamin D, and fortified foods are not consistently available,” Dr Sharma explains. “This makes deficiency more likely in colder seasons.”
Why supplementation becomes necessary
All these factors explain why winter sunlight fails to correct or prevent deficiency, even with regular exposure. Dr Sharma emphasises: “It is safe and reliable to consider supplementation during winter, especially for people who already have a deficiency, or are at high risk, such as older adults, obese individuals, and those with chronic illnesses.”She adds that monitoring is essential: “Periodic testing and personalised supplementation help maintain optimum levels despite seasonal limitations.”
Also read: Vitamin D deficiency symptoms, causes, and best food sources to increase your intake
