A little history of Vitamin D
If you do some research online, and offline, as I did, you’ll find a lot of slightly different tales depicting the history of Vitamin D. My personal favourite is that found on Wikipedia about the American researchers Elmer McCollum and Marguerite Davis, who in 1914 (a time when the bone deformity, rickets, was rife in north-eastern USA and northern Europe) discovered a substance in cod liver oil which was named, “vitamin A”. Then it seems a British doctor by the name of Edward Mellanby somehow noticed that dogs fed with cod liver oil didn’t develop rickets and concluded that vitamin A, or a closely associated factor, could prevent the disease. In 1922, Elmer McCollum tested modified cod liver oil in which the vitamin A had been destroyed. The modified oil cured the sick dogs, so McCollum concluded that the factor in cod liver oil which cured rickets was distinct from vitamin A. He called this factor vitamin D, because it was the fourth vitamin to be named. There lies the birth of vitamin D.
Vitamin D plays an important role in bone health, as well as in immune, nerve and muscle function. In addition, it may play a role in protecting against cancer, heart disease, stroke, diabetes, auto-immune diseases, and depression.
In 1971, vitamin D was reclassified as a “vitamin D hormone,” meaning that it can act as both a vitamin and a hormone. In people that live near the equator and who are constantly exposed to sunlight throughout the year, vitamin D is a hormone that their bodies can build in sufficient amounts for them. Yet people that live far from the equator, where sunlight is limited, or those that have an indoor lifestyle, where there is a significantly lower exposure to sunlight, an alternative becomes necessary. This would come in the form of fortified foods, or by supplement intake. The Recommended Dietary Allowance (RDA) is 15 mcg for adults under 70. So my advice is to sit outside in the sunshine every day whilst eating your breakfast of grilled mushrooms with cereal, orange juice, coffee with soy milk, and you’ll be just fine. However, if you feel this will fall short on your RDA, then grab some supplements to top up.
As always, I hope you have enjoyed reading this as much as I’ve enjoyed writing it. Tomorrow we’ll look at Omega 3 Fatty Acids (DHA & DPA), their function, and how we can get more of them.