Causes of Vitamin D Deficiency:
The most important cause of vitamin D deficiency is limited or no exposure to sunlight. However, even in countries like India where there is plenty of sunlight, it is still quite common. Why is this? To understand other factors, you need to understand how vitamin D is produced, processed, stored, and used by the body.
Upon exposure to UV B in the sun’s rays, the epidermis (the upper layer of the skin) converts cholesterol into provitamin D3, which enters the bloodstream and is transferred to the liver. Vitamin D also comes from foods/supplements, absorbed from the stomach, and sent to the liver. The liver converts it to a more potent form.
It is then transferred to the kidneys where it is converted to calcitriol – this form is actively ready to work. So, now it is easier to understand that vitamin D deficiency can be created in the following situations even after being in good sunlight.
Decreased Acceptability Of Vitamins In Food: Strict vegan diet, dietary habits (low intake of vitamin-rich foods), elimination diet (milk allergies), etc.
Increasing Depletion: Drugs such as anticonvulsants, anti-tuberculosis, steroids that may interfere with the process of vitamin D production or absorption.
Low vitamin D synthesis: Dark skin, ultraviolet rays, sunscreen lotions and clothing, latitude (UVB is not very effective in sunlight in the UK for example), seasons, air pollution, limiting the time spent outside of children and adolescents Vitamin D synthesis is reduced due to air-conditioned housing, colored glasses, light-sensitive skin conditions, etc.
Decreased Maternal Vitamin D Storage: Exclusive breastfeeding where the mother does not store enough vitamin D in her body to nurture the child.
Defective synthesis: Chronic liver disease, kidney disease, etc. can lead to improper functioning of the organs required for the production and absorption of vitamin D.