Micronutrient deficiencies remain a global concern and challenge, including in India. In early September, The Lancet Global Health published a study highlighting that millions of people worldwide are deficient in essential micronutrients, including iodine, vitamin E, calcium, iron, riboflavin, and folate. Other than these critical micronutrients, Vitamin D, which is vital for overall health, remains the most underdiagnosed and undertreated nutritional deficiency globally.
Vitamin D plays an important role in our body. While it acts as a hormone with multiple cellular and molecular functions, its most essential role is facilitating calcium absorption in the gut. Without vitamin D, dietary calcium doesn’t effectively reach our bloodstream or bones. Research suggests that vitamin D may help prevent acute upper respiratory tract infections. Vitamin D has been shown to reduce conversion of prediabetes to diabetes and help long term cancer prognosis. Mortality benefits of administering vitamin D have also been shown in the elderly.
Adults severely deficient in vitamin D are prone to osteomalacia, a condition that leads to bone softening, deformity and fractures. Its deficiency in children can cause rickets, a condition marked by weak bones and stunted growth. For many, mild to moderate deficiency persists over time, leading to inadequate calcium absorption and contributing to bone damage that may eventually present as low bone density and fractures in later years. In clinical terms, individuals with vitamin D (25-OHD) levels below 20 ng/ml are considered vitamin D insufficient while anything below 12 ng/ml is classified as deficiency. Interestingly, even in tropical countries like India, where sunlight is abundant, vitamin D deficiency is widespread. According to the 2019 Comprehensive National Nutrition Survey (CNNS) by the Ministry of Health and Family Welfare (MoHFW), Government of India, the overall, nationwide prevalence of levels below 12ng/mL amongst Indian preschool children was 14%, rising to 24% amongst adolescents, with major regional differences. If the criterion of 20 ng/ml is used the figure will be much higher.
Sunlight remains the principal source of vitamin D, but many Indians have poor sunlight exposure. Indians tend to have sun fleeing behaviour, preferring to spend more time indoors. Atmospheric pollution reduces the ability of sunlight to reach the skin, thereby drastically reducing synthesis of vitamin D. The adverse effects of low vitamin D are compounded by poor dietary calcium intake in many parts of India. Dietary sources such as fatty fish which are consumed in Japan are not popular or available in India. Egg yolk contains small, insufficient amounts of vitamin D.
There are other promising and sustainable solutions to address vitamin D deficiency, such as fortification of commonly consumed foods with vitamin D. Globally, several countries such as the United States, Finland, and Canada have long embraced fortification of foods such as milk, orange juice, and cereals, significantly improving national vitamin D levels and public health. Finland’s example is particularly compelling. With over 11 years of food fortification, vitamin D levels improved substantially across the population, cutting deficiency rates and promoting better health outcomes. In Canada, increased fortification policies have led to better bone health and reduced fracture rates. These successes underscore that vitamin D fortification, when implemented as part of a comprehensive strategy, yields significant health benefits. The safety margin of vitamin D is wide, and the safety of such an approach has been repeatedly established. The amounts added are a small proportion of the recommended daily allowance, enough to improve the overall status and ward off severe disease, but not enough to lead to side effects or toxicity. In particular, such an approach is expected to help children in their growing years, pregnant women, and the elderly. Supplementation is another option particularly for susceptible groups mentioned above, but without proper medical supervision, overconsumption can lead to toxicity. Poor compliance and greater costs are other issues with this approach.
Based on the standards set by Food Safety and Standards Authority India (FSSAI), India started fortifying milk and edible oil with vitamin D in 2018. This step marked a critical milestone in combating widespread Vitamin D deficiency. While rare, vitamin D toxicity has been reported form India in people consuming excess doses of vitamin D (usually more than 10 times greater than the recommended therapeutic dose, and at least 50 times more than fortified food is expected to provide) either based on incorrect prescriptions or on their own. Toxicity is never seen if appropriate doses are used.
India’s population stands to gain immense benefits from scaling up fortification efforts. Fortified foods, especially when made easily accessible through government safety schemes, can provide consistent and affordable sources of vitamin D. The World Health Organization (WHO) recommends fortifying foods with essential nutrients for populations at risk of deficiency, yet many countries have been slow to adopt fortification policies. Given the cost-effectiveness of fortification, it can reduce the burden on healthcare systems by lowering rates of vitamin D-related diseases. For a country like India, where healthcare resources are already stretched thin, the potential savings are significant.
It is important that we consider the key lessons and good practices from countries which have already implemented vitamin D fortification policies, and carefully assess the safety of food-based solutions. As India moves towards widespread fortification, studies to assess the impact on health parameters are crucial. The amount of vitamin D added may have to be increased/changed, and use of food products other than milk and edible oil may have to be considered to ensure a wider reach.
Governments, public health organisations, and food manufacturers must come together to make fortified foods widely available. Vitamin D deficiency may be a silent epidemic, but through fortification, it can be addressed directly, helping to build a healthier, more resilient India. The time for national action on vitamin D fortification is now.
This article is authored by Dr Ambrish Mithal, endocrinologist and chairman and head of endocrinology and diabetes, Max Healthcare, Saket, New Delhi.
