Just last month, a 30-year-old man came to me with complaints of severe back pain and muscle weakness. He had trouble walking and was about to end up in a wheelchair. Although the typical orthopedic evaluation was inconclusive, a metabolic diagnosis revealed a severe vitamin D deficiency (osteomalacia – a condition in which the bones lose minerals and become soft and malleable). Fortunately, the patient is well on his way after vitamin D treatment.
Any doctor practicing medicine in India would have seen such vitamin D deficient patients with bone/muscle pain and weakness, often along with fractures. In children, a severe vitamin D deficiency presents as rickets – the growing bones become bent and deformed. The condition has been virtually eradicated in Europe and the United States thanks to systematic public health interventions such as fortifying foods with vitamin D. In India, however, vitamin D deficiency is still observed in both children and adults. In fact, in the last few months there has been an increasing number of patients – children and adults – with such symptoms. This is just a gift from the pandemic, with people locked up indoors.
These cases are just the tip of the proverbial iceberg. A much larger number of Indians suffer from mild to moderate vitamin D deficiency. For many, a low-grade deficiency lasts for a long time, resulting in poor calcium absorption and contributing to bone damage that can potentially manifest with low bone density and fractures in old age.
Several studies suggest a high prevalence of low blood levels of vitamin D (25-OHD) in people in India. Depending on the threshold used and the population studied, the prevalence of vitamin D deficiency across India ranges from 17 to 90%. Although all ages are affected, deficiency appears to be more common in cities than towns, and more in the north than in the south, which is closer to the equator. As late as 2020, as many as 25% of patients hospitalized with covid at a major Delhi hospital had levels below 10 ng/ml!
What is the role of vitamin D in our body? While vitamin D is a hormone that has numerous actions in the body at the cellular and molecular levels, its primary, critical role is to help absorb calcium from our gut. In the absence of vitamin D, dietary calcium does not reach our bloodstream and bones. There is also some evidence that vitamin D helps prevent acute upper respiratory tract infections. There are some differences of opinion about the level needed for optimal human health. Most experts recommend levels of 20 ng/ml for overall bone health in adults and levels of 12 ng/ml to prevent rickets in children.
The main source of vitamin D is not our food, it is sunshine. So why does a sunny country like India have such a high prevalence of D deficiency? The responsible factors are our sun-fighting behavior (as opposed to the sun-seeking behavior of the people of Europe and the United States); professional and personal reasons for spending most of the time indoors; cultural reasons for keeping our body parts completely covered when we go out; air pollution, which has been shown to inhibit the synthesis of vitamin D. In cities like Delhi, supervised exposure of children to the midday sun for 30 minutes a day (the best time to make vitamin D) did not lead to a significant rise in blood levels.
A multi-pronged strategy is needed to address this public health problem (diversification of diets, exposure to sunlight, consumption of fortified milk and the use of supplements when indicated). Vitamin D fortification of popular and commonly used products such as milk and edible oil, as recommended by the Food and Safety Standards Authority, is an established approach. The recommended average daily intake of vitamin D through fortified milk and oil (240 IU) may not be sufficient to bring serum levels of vitamin D within the normal range, as shown by a recent study.
However, it is an essential step in the right direction and should logically lead to mandatory fortification and ultimately to a revision of the amount of vitamin D to be added. milk fortification with vitamins A and D with the intention of moving to mandatory fortification of the two staples. However, not much has happened since then.
While food fortification isn’t a panacea, it remains one of the most tangible and cost-effective ways to hit the last mile to improve health and nutritional outcomes, especially in the short term. It also strengthens and supports ongoing nutritional improvement programs and is an essential part of a broader, integrated approach to prevent micronutrient malnutrition, complementing other approaches to improve micronutrient status. The World Health Organization and the World Bank suggest that fortification is a widely recognized and highly cost-effective strategy for increasing nutrient intake, one that requires no change in eating behavior or substantial government budgets. The success story of universal salt iodization and its role in eradicating iodine deficiency is one of India’s greatest public health success stories.
Achieving the goal of a malnutrition-free India calls for scaling up efforts such as fortification. As was the case with the iodization of table salt, it is time for all stakeholders to join forces for fortification to reduce and prevent debilitating conditions caused by vitamin D deficiency.