Why Is Vitamin D Deficiency Increasing in India?

Vitamin D deficiency has emerged as a major public health challenge in India, affecting nearly half the population despite the country’s tropical climate and year-round sunshine. Recent studies, including a comprehensive report by ICRIER-ANVKA (2025), reveal that about one in five Indians suffers from severe vitamin D deficiency, with children, pregnant women, and older adults being the most vulnerable groups.^[1]

This deficiency is not only linked to skeletal disorders like rickets and osteomalacia (softening of the bones), but some studies have shown a potential correlation between vitamin D deficiency and cardiovascular diseases, type 2 diabetes, autoimmune diseases and certain cancers.^[2]

The rising prevalence underscores the urgent need for awareness, routine screening, and targeted interventions to combat this growing health crisis.

Common Causes of Vitamin D Deficiency in India

Vitamin D deficiency in India is caused by a combination of lifestyle, environmental, dietary, and medical factors. Although India receives abundant sunshine throughout the year, many people do not get enough ultraviolet B (UVB) exposure or dietary vitamin D to maintain healthy levels. The following are some of the most common causes of vitamin D deficiency in India.

1. Spending Less Time Outdoors

Many people spend most of their day indoors due to work, school, or household responsibilities. As a result, they have limited exposure to direct sunlight, which is essential for vitamin D production in the skin. Children and adults living in urban areas are particularly affected because outdoor activities have decreased significantly over the years.

2. Indoor Work and Screen Time

The increasing number of office-based jobs, remote work, online education, and recreational screen time means many people remain indoors throughout daylight hours. Even when indoors near windows or travelling in vehicles, glass blocks most UVB rays required for vitamin D synthesis. This makes prolonged indoor living an important contributor to vitamin D deficiency despite living in a sunny country.

3. Air Pollution Reducing UVB Exposure

Air pollution is another major factor contributing to vitamin D deficiency in India. High levels of airborne pollutants reduce the amount of UVB radiation reaching the earth's surface, making it harder for the skin to produce vitamin D. The problem is especially significant in heavily polluted cities and may become worse during winter and the monsoon when sunlight exposure is already reduced[4].

4. Skin Pigmentation and Vitamin D Production

Melanin, the natural pigment that gives skin its colour, acts as a natural sunscreen by reducing UVB penetration into the skin. Since most Indians have medium to dark skin tones, they generally require longer periods of sun exposure to produce the same amount of vitamin D as people with lighter skin. This natural biological factor contributes to the high prevalence of deficiency across the country[3].

5. Dietary Patterns Low in Vitamin D

Very few foods naturally contain vitamin D, making it difficult to meet daily requirements through diet alone. Indian diets are often low in vitamin D-rich foods such as fatty fish, egg yolks, and liver. In addition, vitamin D-fortified foods are not yet widely consumed, increasing the risk of inadequate intake.

6. Rising Rates of Obesity

Obesity is associated with lower circulating vitamin D levels. Vitamin D is a fat-soluble vitamin and may become stored in body fat, reducing the amount available for use by the body. As obesity becomes increasingly common in India, it is also contributing to the growing burden of vitamin D deficiency [5].

7. Vegetarian and Vegan Diet Patterns

Many Indians follow vegetarian diets for cultural, religious, or personal reasons. While these diets offer many health benefits, they naturally contain fewer dietary sources of vitamin D because foods such as fatty fish and egg yolks are excluded or consumed less frequently. Unless fortified foods or supplements are included, maintaining adequate vitamin D intake may be difficult.

8. Ageing Population

The skin gradually becomes less efficient at producing vitamin D as people age. Older adults may also spend less time outdoors due to reduced mobility or chronic illnesses, further limiting sun exposure. Together, these factors make vitamin D deficiency more common among the elderly population.

9. Chronic Health Conditions Affecting Absorption

Certain medical conditions can reduce the body's ability to absorb or utilise vitamin D effectively. Disorders such as coeliac disease, inflammatory bowel disease, chronic liver disease, and some kidney disorders may interfere with vitamin D metabolism or absorption, increasing the likelihood of deficiency.

10. Medicines That Can Lower Vitamin D Levels

Some medicines can interfere with vitamin D absorption or metabolism, leading to lower vitamin D levels over time. Examples include certain anticonvulsants, glucocorticoids, antifungal medicines, and medicines used to treat tuberculosis or HIV. People taking these medicines for long periods should consult their doctor about monitoring their vitamin D status if clinically indicated.

Who Is Most at Risk of Vitamin D Deficiency?

• Older adults
• Pregnant and breastfeeding women
• Infants
• Office workers
• People with obesity
• People with gastrointestinal disorders
• People with darker skin tones
• People taking certain long-term medicines (e.g., anticonvulsants, glucocorticoids)

Conclusion

Despite rising vitamin D deficiency in India, the solution remains within our reach. Addressing this issue requires public awareness, routine screening, nutritional interventions, and lifestyle changes to ensure adequate vitamin D levels for better health outcomes. The ICRIER-ANVKA report (2025) and other studies highlight the urgent need for a national strategy, including food fortification, public awareness campaigns, and affordable testing and supplementation, to combat this silent epidemic and improve public health in India.