Delhi's Toxic Air Hides Another Health Crisis: 'Sunshine Vitamin' Deficiency

As air quality across Delhi and the National Capital Region (NCR) worsens, a hidden health concern is emerging - a surge in vitamin D deficiency. With thick smog cutting off sunlight, doctors are now urging residents to take supplements for the vitamin.

On Wednesday, Delhi's Air Quality Index (AQI) stood at 325, placing it firmly in the 'severe' range. At least ten monitoring stations reported 'very poor' air quality, while PM 2.5 levels in several localities touched 350 micrograms per cubic metre - more than 30 times higher than the World Health Organization's safe limit.

"Vitamin D is produced when our skin absorbs UVB rays," explained Dr Lohit Chauhan, Gastroenterologist at Max Hospital, Dwarka. "Air pollution filters out these rays and increases inflammation in the body, both of which reduce vitamin D synthesis. Even in a country with abundant sunlight, we are facing 'sunshine deficiency' because the smog blocks it out."

Vitamin D, often referred to as the "sunshine vitamin," is essential for bone strength, immune function, and the regulation of calcium and phosphorus levels.

Dr Aprajita Pradhan, Endocrinologist at Vedanta Super-speciality Clinic, noted that air pollution also increases oxidative stress, raising the need for antioxidant vitamins like C, E, and A.

One In Five Indians Deficient

A report titled 'Roadmap to Address Vitamin D Deficiency in India', published by the Indian Council for Research on International Economic Relations (ICRIER) and the Anvka Foundation earlier this year, found that one in five Indians suffers from vitamin D deficiency.

The problem is particularly acute in eastern India, where nearly 39 per cent of people are affected. High deficiency rates have also been recorded among adolescents, newborns, and the elderly.

Experts say the condition is more common in cities due to limited outdoor activity, high-rise living, sunscreen use, and heavy pollution. Research consistently shows that vitamin D deficiency is significantly higher in urban than rural populations.

"To prevent deficiency, especially in polluted urban areas, people should maintain healthy vitamin D levels through sunlight exposure during cleaner seasons and by consuming vitamin D-fortified foods," said Dr Pradhan. Common signs of deficiency, she said, include fatigue and muscle or bone pain, and people who are deficient also have a higher risk of fractures.

Doctors Recommend Preventive Supplementation

With Delhi-NCR facing long months of poor sunlight, doctors are recommending preventive supplementation for residents. Adults are advised to take about 2,000 IU (International Units) of vitamin D daily, while adolescents may require 1,000 IU and children between 600 and 1,000 IU.

"Most adults need around 400-800 IU daily but in polluted regions, slightly higher doses may be helpful," said Dr Chauhan. "However, excessive, or unsupervised intake can be harmful. Very high levels can cause vitamin D toxicity, leading to elevated calcium in the blood, or hypercalcaemia, which can result in nausea, vomiting, weakness, bone pain, and kidney problems."

Which Natural Foods Contain Vitamin D?

Vitamin D can be naturally obtained from foods such as fatty fish, cod liver oil, and egg yolk, and from fortified products like milk, orange juice, and cereals.

Last year, the United States Endocrine Society advised against routine vitamin D testing and supplementation for healthy adults under 75, citing risks of overuse.

However, Indian doctors argue that these recommendations must be seen in context. Despite its sunny climate, India is grappling with widespread vitamin D deficiency due to smog, indoor lifestyles, and urban pollution.

Doctors recommend combining supplements with simple lifestyle measures. These include spending 10-30 minutes in safe sunlight a few times a week when air quality allows and including foods rich in vitamin D in your diet. They also advise consulting a medical professional if you experience fatigue, muscle weakness, or bone pain.