India may be a tropical country, but vitamin D deficiency remains widespread, especially in cities. While many people assume that simply “standing in the sun” is enough, doctors say the biology is far more complex. Sunlight is necessary, yes, but sunlight exposure and vitamin D status are not the same thing.
According to Dr Pranav Ghody, Consultant Endocrinologist & Diabetologist at Wockhardt Hospitals, Mumbai Central, winter makes that gap even wider. The weather, lifestyle and environmental factors all combine to make vitamin D harder to get, even on bright sunny days.
Why are so many Indians deficient despite abundant sunlight?
India gets plenty of sunshine, but most of us don’t get the right kind of sunlight. Vitamin D is produced only when UVB rays hit the skin, and that depends on timing, angle and exposure.
Dr Ghody explains: “Sunlight alone doesn’t guarantee enough Vitamin D. What really matters is UVB exposure, which depends on the angle, time of day, skin type, and pollution levels.”
Work hours, indoor lifestyles, and clothing make things worse. Many Indians are indoors during peak UVB hours (10 am–2 pm), limiting the body’s ability to create vitamin D naturally.
Why is winter sunlight less effective
Winter sun may feel warm, but it delivers much less UVB radiation.
“The sun sits lower in the sky, and more UVB rays get filtered before they reach the ground,” says Dr Ghody.
Two practical issues worsen this gap:
- More clothing layers cover the skin
- Pollution peaks in winter, blocking and scattering UVB rays
So even if someone spends 20–30 minutes outdoors, the vitamin D produced in winter is significantly lower.
How skin tone affects vitamin D levels
Melanin, the pigment that gives skin its colour, acts as a natural sunscreen.
“People with medium to dark skin need a lot more sun exposure to produce the same amount of Vitamin D as those with fair skin.”
In winter, when UVB is already low, this becomes especially challenging for people with darker skin tones, indoor jobs, or those living in polluted cities.
Is sunlight ever enough, or do we need supplements?
Sun exposure can help mild deficiency, but for most urban Indians, winter sunlight alone is rarely enough, says Dr Ghody.
Dietary sources like fortified milk, eggs, mushrooms and fish can support levels, but they contribute only a fraction of daily needs.
“People with ongoing deficiency often need medically supervised supplements to safely restore levels.”
Importantly, supplements should not be self-prescribed. Too much vitamin D can be harmful.
How to maintain vitamin D levels in winter
Dr Ghody recommends simple strategies:
- Aim for brief sun exposure between 10 am–2 pm on clearer days
- Include fortified foods and vitamin D-rich ingredients
- Discuss supplementation if you’ve had a deficiency before
- Monitor symptoms like fatigue, bone pain, muscle weakness, or low immunity
Winter is the season when vitamin D naturally dips; planning helps prevent deficiency-related problems.
In India, sunlight is everywhere, but usable vitamin D is not. Winter sun is weaker, pollution is higher, and daily habits keep skin covered or indoors during prime UVB hours. Relying only on sunlight can leave many people deficient without realising it.
The solution isn’t to chase sunlight obsessively, but to combine smart exposure, supportive diet and, when necessary, medical supplementation. Because maintaining vitamin D isn’t about more sun, it’s about better strategy.
Also read: Vitamin D deficiency symptoms, causes, and best food sources to increase your intake
