Vitamin D is commonly known as the “sunshine vitamin,” and for good cause. Our our bodies can produce it when uncovered to daylight, and it seems to play an vital function not solely in bone and mineral metabolism, but additionally in immunity and even temper regulation. Though vitamin D may be produced within the physique, deficiencies of this vitamin seem like widespread at a world stage, and much more so in sun-rich nations similar to India.
Understanding vitamin D
Vitamin D is a fat-soluble vitamin together with vitamin A, vitamin Ok, and vitamin E. In contrast to water-soluble nutritional vitamins similar to vitamin B, fat-soluble nutritional vitamins are tough to excrete within the urine, and in the event you soak up greater than vital, they’re extra prone to trigger toxicity.
Vitamin D2 (Ergocalciferol): Vitamin D ranges are typically very low on a vegetarian eating regimen. It’s present in small quantities in almonds and mushrooms.
Vitamin D3 (cholecalciferol): Present in excessive concentrations in animal meals similar to fish, eggs, and liver.
As soon as within the physique, nutritional vitamins D2 and D3 are transformed within the liver to calcidiol (25-hydroxyvitamin D), this manner is measured in blood exams, after which transformed within the kidneys to the physique’s lively molecule, calcitriol. The complexity of this pathway partly explains why vitamin D ranges are low, although the physique can produce it.
The day by day requirement for vitamin D for youngsters and adults is 600 to 800 IU/day. For older adults, it is about 800 to 1,000 IU per day, relying in your threat profile, and for pregnant girls, 1,000 to 1,200 IU per day.
These ranges have been recognized by professional group consensus based mostly on absorption of calcium from the gut, elevated parathyroid hormone ranges as a manifestation of altered bone mineral metabolism, and elevated fractures in older adults.
The definition of deficiency varies between pointers, however a consensus assertion identifies the next blood ranges:
Deficiency – <20 ng/dl
Deficiency – 21 – 30 ng/dl
Adequacy – 31-75 ng/dl
Toxicity stage – > 100 ng/dl
Epidemiology of deficiency illnesses
Vitamin D deficiency is frequent worldwide. In India, 30-50% of the inhabitants has vitamin D ranges under 20 ng/dl, which is increased than what’s seen in developed nations such because the UK and the US. Doable causes for this embrace low solar publicity, air air pollution, a vegetarian eating regimen, and lack of fortification of dairy merchandise on this nation.
Analysis over the previous a number of a long time has expanded our understanding of the significance of vitamin D far past the skeletal system. Vitamin D receptors are current in practically all human tissues, indicating that vitamin D receptors affect a number of organ methods. These extraskeletal influences impression immunity, cardiovascular well being, metabolic perform, and even psychological well being. Nevertheless, by way of extraskeletal results, a causal relationship between vitamin D deficiency and these illnesses has not been established.
Nevertheless, vitamin D deficiency has been linked to poor stability and muscle weak point. Many research have discovered an affiliation between falls and low vitamin D ranges in older adults.
Vitamin D additionally performs a job in regulating each innate and adaptive immunity. Deficiency is related to elevated susceptibility to infections similar to respiratory tract infections and tuberculosis. Vitamin D deficiency can be considered concerned in cardiovascular problems and metabolic problems similar to diabetes. Nevertheless, these associations haven’t but been proven to be causal and will require additional analysis.
Therapy of vitamin D deficiency
In lots of nations, obligatory meals fortification has been famous to be an economical technique to manage widespread vitamin D deficiency. Nevertheless, the technique mandates that testing for vitamin D ranges be extensively obtainable throughout the nation to detect toxicity, which is at present not obtainable in India.
Testing and therapy are different methods. Comply with-up blood exams are often completed two to a few months after you begin taking the complement.
This text first appeared in The Hindu’s e-book Care and Treatment.
(Kurien Thomas is a Senior Guide, Doctor and Scientific Epidemiologist, Narvi Hospital, Vellore. kurien.t@naruvihospitals.com; Pranita Vanjare is a Guide, Geriatrics and Inner Medication, Narvi Hospital, Vellore. pranita.r@naruvihospitals.com)
issued – January 23, 2026 3:30 PM IST
