by Leslie Ellis

Created on: March 17, 2009

Actually, the information in the article by Sandra Arana is incorrect. First, it is vitamin D2, not D12. Secondly, vitamin D is actually found in relatively few foods in nature. Plant-wise, mushrooms are your best source. And, as you mentioned, fortified milk, beef, veal, some fatty fish and egg yolks are all good sources.

Another glaring inaccuracy is that sunscreen that protects against UVB rays (and they all do) will indeed prevent sun from reaching the skin. Therefore, it will prevent the process through which our body can make vitamin D upon exposure to sunlight. And actually, according to the research, wearing a sunscreen with a SPF of just 8 blocks vitamin-D producing UVB rays from penetrating your skin (please see the NIH Fact sheet about Vitamin D for more information). So yes, wearing sunscreen will definitely inhibit your body's production of vitamin D. I do not advocate not wearing sunscreen (especially since I wear it everyday) but the majority of people shouldn't count on the sun for meeting their vitamin D needs.

In addition to sunscreen inhibiting our body's production of this vitamin, UVB rays do not penetrate glass so exposure to sun while you are driving your car will not help your body produce vitamin D. Cloud cover, smog and skin melanin content (the pigment that makes skin dark) also affect UV radiation exposure and therefore, our bodys ability to produce vitamin D. The UV index must be 3 or higher for the body to make vitamin D from the sun. For those living north of the 37th latitude or Atlanta, Georgia, if is virtually impossible to get any vitamin D from the sun during the winter months due to the low UV index.

It should come as no surprise, given the few foods that contain vitamin D and lack of production through sun (because of many variables), that a number of people in the U.S. are in fact vitamin D deficient. According to study highlighted on the National Institutes of Health website, many teens today arent getting enough vitamin D and half of black teenagers may be vitamin D deficient (http://www.nlm.nih.gov/medlineplus/news/fullstory_8 1307.html). Infants are also at risk for low vitamin D levels hence the American Academy of Pediatrics doubled the recommendation for infants from 200 IU to 400 IU per day.

Other groups at risk for deficiency include breastfed infants, older adults (older adults are less able to synthesize vitamin D efficiently), individuals with dark skin, people with fat malabsorption issues, people who are obese and those with little sunlight exposure to begin with. There are indeed many groups of individuals who are at risk for low vitamin D levels.

Vitamin D deficiency has been linked to many chronic diseases, soft bones (osteomalcia), osteoporosis, weak muscles, iabetes, immune system problems and some inflammatory diseases.

This information was provided to me by Marie Spano, MS, RD, FISSN, CSCS

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