By Yang Wei Ling & Nor Aini Jamil
Back in the 1920s, Steenbock and Archie Black discovered that exposing foods to mercury vapour lamps and feeding them to rats with Rickets helped promote their growth and calcium absorption; similar positive effects were observed when rats were directly irradiated. Later, Hess and Weinstock also reported that ultraviolet irradiated cottonseed oil, linseed oil, wheat germ, and lettuce as potent antirachitic agents. Based on these observations, they speculated that it could be considered as a vitamin if the anti-Rickets factor in irradiated foods was comparable to the cod liver oil. This marks the birth of vitamin D, a fat-soluble vitamin. Vitamins A, B and C were already found at that time, so it had to be called D.
Vitamin D is essential for regulating calcium and phosphate metabolism, which play a vital role in maintaining bone health. Inadequate amounts of vitamin D can cause rickets or osteomalacia. Vitamin D has also been associated with other functions such as immune function, cell growth regulation, neuromuscular function and reducing inflammation. However, it is still debatable if a healthy level could help to reduce the risk of non-skeletal disease.
