Vitamin D is more than just a vitamin; it also acts as a hormone. It is available in very few food items; fatty fish like salmon and tuna have it. This particular vitamin is needed for calcium absorption and cell growth.
A diet deficient in Vitamin D in conjunction with inadequate exposure to the sun can cause Osteomalacia (or rickets when it occurs in children) which is softening of the bones caused by defective bone mineralisation. Change in lifestyle is resulting in more cases of Osteomalacia caused by Vitamin D3 deficiency. Despite the high cost (Rs. 900 to Rs. 1,000) per test to check Vitamin D level in the blood, this investigation is becoming a routine for the elderly across the world.
Vitamin D exists in several forms, but the two major forms are Vitamin D2 (Ergocalciferol) and Vitamin D3 (Cholecalciferol). Vitamin D2 was chemically characterised in 1931 and the chemical structure of Vitamin D3 was established in 1935. City-based endocrinologist Goutham Meher says it is a general misconception that the pleasant rays of the early morning sun are rich in Vitamin D. It is the harsh rays of the sun available between 11 a.m. and 3 p.m. that are actually required to convert 7-dehydrocholesterol to Vitamin D3. This Vitamin (D3) is not produced if sunscreen lotion is used as it prevents much of it from reaching the skin. Sunscreen lotions with Sun Protection Factor (SPF) of 8 (based on the Ultra-Violet B spectrum) have been reported to decrease Vitamin D synthetic capacity by 95 per cent, whereas sunscreen with SPF of 15 reduces synthetic capacity by 98 per cent.
Depending on the intensity of the Ultra-Violent light and time of exposure, the Vitamin develops in the skin and also degrades as fast as it is generated.
Unlike other vitamins, great care should be taken while taking Vitamin D orally. It must be taken under the guidance of a physician, preferably an endocrinologist because D3 also functions as a hormone. People deficient in Vitamin D must take the exact dose of Vitamin D3 because excess dose may disturb the calcium balance in the body. The bones are the biggest source of calcium in the body and they get affected if there is an imbalance in the Vitamin D, Dr. Meher cautions.
It is a general misconception that the pleasant rays of the early morning sun are rich in Vitamin D. It is the harsh rays of the sun available between 11 a.m. and 3 p.m. that are actually required to convert 7-dehydrocholesterol to Vitamin D3
Goutham Meher
Endocrinologist
