There's been a lot in the news lately about vitamin D. There seem to be new reports every day about the results of research studies and what they might mean for you and your family. Different terms are often used in the reports. This is not only confusing, but makes it difficult to act on the information.
Types
Vitamin D comes in two forms: Vitamin D2 that is produced by plants and invertebrate animals, and vitamin D3 that is produced by vertebrate animals. The term vitamin D used alone can refer to each of these separately or include them both. The Vitamin D Council recommends using only D3 as a supplement. These two forms of vitamin D are not interchangeable. D2 is not as easily converted to the bioactive form for humans and vertebrate animals.
Considerations
Some strict vegans use D2 by choice, but they must adjust the dose and use much more than would be required with D3. In order to get the most from your vitamin dollar, do read the label and be sure it is D3 that is in the product. The following clear and definitive statement is from "The American Journal of Clinical Nutrition ": The scientific community is aware that these molecules are not equivalent. Therefore, vitamin D2 should no longer be regarded as a nutrient appropriate for supplementation or fortification of foods.
Facts
Ergocalciferol is the chemical name for vitamin D2. Cholecalciferol is the chemical name for vitamin D3. Vitamin D3 is the one that you synthesize with sunlight on your skin or take as a D3 supplement. The milk produced by mammals contains cholecalciferol. In nature, it is produced by the action of the sun on the skin. Since sun exposure varies, the amount produced naturally will vary. In order to assure there is a minimum amount of the vitamin in cow's milk, it is irradiated during processing.
Prevention/Solution
The Vitamin D Council urges a higher daily intake of cholecalciferol than the recommended daily allowance. Vitamin D can be tested by your physician with a simple blood test and your vitamin intake adjusted at his recommendation. If the blood level is maintained in the high normal range, the body will be more able to deal with a sudden need for more. Pregnancy is one of these situations. Prenatal use of a good D3 supplement may benefit your unborn baby in many ways, including being a basic ingredient for strong, healthy bones. The baby should also receive a supplement after its arrival. Breast milk, while otherwise the perfect baby food, does not contain enough vitamin D.
History
The original source for a vitamin D3 supplement was cod liver oil. According to the "Official Journal of the American Academy of Pediatrics", although the vitamin itself had not yet been discovered, cod liver oil was a popular folk remedy to relieve such complaints as rheumatism, aching muscles and stiff joints. During the 1890s, it was commonly used to treat rickets, which affected nine out of 10 malnourished children. Cod liver oil has excessive amounts of vitamin A, so it is no longer recommended.
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