Vitamin D deficiency is a global issue. The prevalence of Vitamin D deficiency in a tropical country like India where sunshine is abundant is widespread. Vitamin D deficiency affects 70-90% of our population. Vitamin D deficiency is adding to the increasing burden of health-related co-morbidities, which could lead to calcium deficiency, bone diseases, and even cardiovascular diseases. Lack of knowledge about its importance in the human body is a big challenge than its availability.
Micronutrients of public health importance in childhood and adolescence generally include iron, vitamin A, iodine and zinc. Multiple micronutrient deficiencies are rampant in India and continue to be a significant public health problem, which adversely affect the health of all the population groups. More recently, vitamin D has received greater attention because of the increasing incidences of Vitamin–D deficiency, worldwide. “Vitamin D” is a fat-soluble vitamin that is naturally present in a few foods, added to others, and available as a dietary supplement. It is also produced endogenously when sunlight ultraviolet (UV) rays strike the skin and trigger vitamin D synthesis (Office of Dietary supplements. (2022). Apart from influencing Vitamin D synthesis sunlight exposure may also influence cholesterol synthesis.
Vitamin D is a micronutrient essential for optimal bone health. It also helps us in decreasing the risk of many chronic illnesses, including common cancers, autoimmune diseases, infectious diseases, diabetes and cardiovascular disease. A sufficient amount of Vitamin D can reduce bone fractures by 20%, cardiovascular disease by 20%, diabetes and cancer by 25%, and multiple sclerosis by 50%. On the other hand, the consequences of Vitamin D deficiency resulting in a variety of skeletal and extraskeletal manifestations and rickets (defective mineralization of bone due to an imbalance between calcium and phosphorous in the bone). Apart that depression, Parkinson's disease, suicide, type 1 diabetes, arthritis, infectious diseases and cancer (Fortification of Milk with Vitamin-D: Strategy To Eliminate Vitamin D Deficiency In India. (2014).
FSSAI has recommended that people with more than 30ng/ml are called Vitamin D sufficient, Vitamin D status around 20 - 39 ng/ml are called Vitamin D insufficient, and less than 20ng/ml are called Vitamin D deficient (Raj, P Dr. (2019).
High prevalence of Vitamin –D deficiency in India
In India, almost every other Indian is Vitamin-D deficient with most of the studies reporting a prevalence of over 90 per cent in infants, 80 per cent in adults and over 96 per cent in the elderly population (Sizar, O., Khare, S., Goyal, A., & Givler, A. (2022). As per another study, 19.7 or more% children and adolescents are Vitamin D deficient but vary for adults and older adults at 19.4 - 87 per cent (Cashman, K. D., Sheehy, T., & O’Neill, C. M. (2019). According to the National Family Health Survey statistics, 2015, an average of 23.9 per cent of old adolescents aged 10–19 years have vitamin D deficiency in India (Health Nutrition India. (2018).
Looking at the zone-wise differences, Based on a systematic review of 4 zones in India (East West, North and South), it was found that people aged 18-30 were most likely to have vitamin D levels below 30 ng/ml, in east India, followed by west, north and south, respectively (73.8%, 63%, 59.7% and 59%) (Goel, S. (2020).
Overcoming Vitamin - D Deficiency
About 90% of the required Vitamin D is synthesized in the skin under sun exposure; the other main dietary sources are fish, fortified food, and supplements, and vegetables and grains are poor sources. It has been recommended that an adult should take 800–1000 IU of vitamin D per day.
Consumption of foods rich in vitamin D
Animal foods such as fatty fish (tuna, salmon, and mackerel), as well as fish liver oils, are excellent natural sources of Vitamin D. Cheese and egg yolks contain small quantities of vitamin D. Mushrooms are also a good source of vitamin D2. Milk, cereals and juices that are fortified with vitamin D are also good sources of Vitamin D.
Regular sun exposure is the most natural way to get enough vitamin D. To maintain healthy blood levels, aim to get 10-20 minutes of midday sunlight (between 11 am to 1 pm), several times per week. People with darker skin may need a little more than this (FSSAI, 2019). Your exposure time should depend on how sensitive your skin is to sunlight. India shares both tropical and subtropical regions in their national map, exposed to more sunlight throughout the year. Natural production of vitamin D synthesis in the human body is adequate in Indian adults (Raj, P Dr. (2019).
In 2018, the FSSAI notified the Food Safety and Standards (Fortification of Foods) Regulations, 2018 in the Gazette of India. With this, in the case of vitamin D, India became the 3rd country in the world to allow fortification. To address micronutrient malnutrition, FSSSAI recommended providing 25%-30% dietary allowances for vitamins A&D. Since vitamins A and D are fat-soluble vitamins, fortification of edible oils and milk with vitamins A and D is mandatory. Out of the limited number of referenced studies, food fortification with Vitamin D showed improved Vitamin D status (25- hydroxyvitamin D) in the population.
Availability of foods fortified with Vitamin D in India
It is essential to take an adequate supplement but not too much i.e. (more than 60ng/ml). According to FSSAI, 2019, supplements are readily available over the counter. A doctor may also prescribe a supplement or multivitamin for Vitamin D sufficiency. For most adults, the recommended dietary allowance (RDA) is 400 - 600 IU. For adults over 70, the RDA is 800-1000 IU. ICMR recommends only 400 IU (10 mcg) of Vitamin D for people with low exposure to sunlight, otherwise, the entire requirement can be obtained just by sunlight (Raj, P Dr. (2019).
Challenges and findings
On one hand, the Indian diet is not rich in Vitamin D because it is mainly vegetarian. As per the survey results, more than half (55%) of children and adolescents consumed a vegetarian (without eggs) diet (CNNS 2016–18 Survey. (2018). On the other hand, Milk & Edible Oil Fortification with Vitamin D provides only 1/3 of an individual's daily requirement of nutrients. To fulfil the rest 2/3rd of the daily requirement, there need to be other Vitamin-D alternatives for sufficient intake. Apart from that, no more evidence ensure fortification is an effective strategy (Food Safety and Standards Authority of India. (2023).
According to a study conducted in North India, Pills, tablets, or granules were found to be the most preferred way of consuming supplements among half of the adults pursuing post-graduation in biotechnology without adequate knowledge. However, they lack knowledge about the minimum daily intake of Vitamin D, its health benefits and the harmful effects of its deficiency in the human body (Arora, H., Dixit, V., & Srivastava, N. (2016). Vitamin D deficiency is the most common undiagnosed, untreated medical problem because of its silent nature. A negative attitude towards sunlight exposure to vitamin D is prevalent among Indians and is a big challenge. Modernization influence humans for staying away from sunlight which can contribute to reducing serum vitamin D levels (Siddiqee, M. H., Bhattacharjee, B., Siddiqi, U. R., & Meshbahur Rahman, M. (2021).
Many studies evidenced that reduced sunlight exposure in populations seems to have an unfavourable effect on lipid metabolism, leading to increased atherosclerosis. In a randomized control trial on Indian men (aged 40–60 years) with Vitamin D deficiency (25-OHD) to assess the effect of increased sunlight exposure, in comparison with Vitamin D supplementation, on Vitamin D status and lipid profile. A significant decrease in Total cholesterol (9.4%) low‑density‑of lipoprotein cholesterol (LDL‑C (7.2%) and a small decrease in HDL‑C (3.3%) were observed in the increased sunlight exposure group. On the other hand, orally administered cholecalciferol supplementation (Vitamin D also increased 25-OHD concentrations) significantly increased the lipids (TC, HDL‑C, and LDL‑C) (Patwardhan, V. G., Mughal, Z. M., Padidela, et. Al. (2017).
Vitamin D deficiency is a common underdiagnosed condition because of its silent nature that has received increasing attention recently. The FSSAI recommend the fortification of vitamin D in oils and milk, some researches support the improvement in children and no such evidence currently exists to reveal the change in health outcomes after using fortified products at a population level. Apart that, adults in India for are not aware of the right source for Vitamin D intake. Supplementation for optimum level of Vitamin D is not a good alternative as it raises the lipids. There is an urgent need to scale up the research on diagnosis of Vitamin D in people, and the effects of fortification and supplementation in the population.
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