New research from the Albert Einstein School of Medicine shows many children have low to very low levels of Vitamin D. A Canadian study, available from the NIH's Pubmed, of healthy young adults also reported widespread wintertime deficiency or insufficiency.
The Einstein study was based upon 6,000 children in the National Health and Nutrition Examination Survey (NHANES) from 2001-2004. "Several small studies had found a high prevalence of vitamin D deficiency in specific populations of children, but no one had examined this issue nationwide," says study leader Michal L. Melamed, M.D., assistant professor of medicine and of epidemiology & population health at Einstein. Subjects with darker pigmentation and lower levels of supplementation seem particularly at risk. Watching television for more than 4 hours a day was also a risk factor.
"Seven out of ten U.S. children have low levels of vitamin D"
The Einstein study, reported in Pediatrics showed a stunning seven out of ten U.S. children have low levels of vitamin D. The lack of the vitamin may be having a major impact on the prevalence of a number of diseases, ranging from bone development and high blood pressure to a number of often deadly cancers. Given the many important function D performs (see Rethinking Vitamin D) the studies suggest supplementation may be called for, echoing the American Academy of Pediatrics, recently updated vitamin D guidelines, which now recommend that infants, children, and teens should take 400 IU per day in supplement form.
"The message for pediatricians is that vitamin D deficiency is a real problem with consequences not only for bone health but also potentially for long-term cardiovascular health. Pediatricians should be screening children for vitamin D levels, especially in the high-risk populations," says Dr. Kumar. A study co-led by Dr. Melamed and published in the Archives of Internal Medicine in August 2008 reported that individuals with low levels of vitamin D may have an increased risk of death from all causes.
"...it's very hard to get enough vitamin D from dietary sources alone"
Dr. Melamed recommends that children should consume more foods rich in vitamin D, such as milk and fish. "But it's very hard to get enough vitamin D from dietary sources alone," she says. Vitamin D supplementation can help. In the study, children who took vitamin D supplements (400 IU/day) were less likely to be deficient in the vitamin. However, only four percent of the study population actually used supplements.
The conclusions of the Canadian study demonstrate that lack of sufficient D is not just a pediatric problem. Canadian researchers found that the problem was also more widespread in young adults than previously reported, particularly in those of non-Eurpoean ancestry. "These data suggest a need to increase vitamin D intake either through improved fortification and/or supplementation." they said.