Vitamin D is not actually a vitamin, but a steroid hormone produced in the body after direct exposure of the skin to ultraviolet B (UVB) radiation in sunlight. Occurrence of diabetes in a population increases in relation to distance from the equator.
Vitamin D and Type 1 Diabetes
Epidemiological studies suggest a link between vitamin D deficiency during infancy and later development of type 1 diabetes. Vitamin D deficiency in breastfed babies results primarily from maternal deficiency during pregnancy and subsequent breastfeeding. Vitamin D deficiency in mothers and children results primarily from lack of sun exposure and use of high-SPF sunscreens.
Vitamin D deficiency may also result from exposure to lead and other toxins, including toxins in breast milk and formula. Lead inhibits vitamin D synthesis. The FDA released a study that found lead in most supplements for women and children (see below).
Vitamin D and Type 2 Diabetes
Vitamin D deficiency has been shown to impair insulin synthesis and secretion in humans, suggesting a role in the development of type 2 diabetes mellitus. In addition to diabetes, vitamin D deficiency has also been associated with increased risk of cardiovascular disease (CVD), as well as with cardiovascular risk factors such as hypertension and obesity.
Vitamin D in Food Sources
Vitamin D occurs naturally in only a few foods, including liver, egg yolk, and fatty fish (salmon, mackerel, sardines, herring, and cod liver oil). Because only these few foods outside of fortified foods (i.e., orange juice, cow's milk) contain significant levels of vitamin D, it is unusual for people to obtain adequate levels of the hormone through dietary sources alone.
Although breast milk typically contains less vitamin D than fortified infant formulas, breast milk contains substances that facilitate and enhance the absorption of nutrients, so the vitamin D in breast milk is highly bioavailable.
According to Cynthia Good Mojab, MS, IBCLC, RLC, in her August 2003 LEAVEN article, "Sunlight Deficiency," exposure to sunlight is the biologically normal means for humans of all ages to obtain sufficient vitamin D. When this is not feasible, a doctor may prescribe therapeutic doses of a vitamin D supplement.
References:
Baz-Hecht M, Goldfine AB. "The Impact of Vitamin D Deficiency on Diabetes and Cardiovascular Risk." Curr Opin Endocrinol Diabetes Obes. 2010 Apr;17(2):113-9. (PMID: 20150805). April 2010.
Mathieu C, Gysemans C, Giulietti A, Bouillon R. "Vitamin D and Diabetes." Diabetologia. 2005 Jul;48(7):1247-57. (PubMed PMID: 15971062). Epub, June 22, 2005.
Shapley, Dan. "FDA Finds Lead in Vitamins." The Daily Green, August 28, 2008.
Mojab, Cynthia Good. " Sunlight Deficiency: Helping Breastfeeding Mothers Find the Facts." LEAVEN, August 2003.
Sara McGrath - Sara is a veteran homeschool mom of three, Usborne consultant, and the author of Unschooling: A Lifestyle of Learning.
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