A new nationally representative study suggests that millions of children in the US between the ages of 1 and 11 don’t have enough vitamin D, and that non-whites, such as black and Hispanic children are especially at risk.
The National Institutes of Health funded study, which is considered to be the most up to date analysis of vitamin levels in American children, was led by Dr Jonathan Mansbach of Children’s Hospital Boston, and colleagues from the University of Colorado Denver and Massachusetts General Hospital, and is published in the November issue of Pediatrics.
Vitamin D is not only important for healthy bones and prevention of rickets in children, but the authors wrote that according to recent studies, it may also prevent many childhood illnesses such as respiratory infections, childhood wheezing and winter-related eczema.
Doctors do not currently agree on the optimal level of vitamin D that should be in children’s blood and how much vitamin D they should take in the form of supplements.
The current recommendation from the American Academy of Pediatrics (AAP) is that children’s vitamin D level should be a minimum of 50 nmol/L (20 ng/ml).
But others suggest that to protect children from heart disease and cancer this figure should be higher, at least 75 nmol/L (30 ng/ml), or even 100 nmol/L (40 ng/ml).
Bearing these recommendations in mind, Mansbach and colleagues analaysed data covering 2001 to 2006 that was taken from a nationally representative sample of about 5,000 healthy children participating in the National Health and Nutrition Examination Survey (NHANES).
They extrapolated the results to the whole US population and worked out that about 20 per cent of children had vitamin D levels that fell below the AAP recommended level of 50 nmol/L, and more than two thirds had levels below the 75 nmol/L, including 80 per cent of Hispanic and 92 per cent of non-Hispanic black children.
Mansbach told the press that:
“If 75 nmol/L or higher is eventually demonstrated to be the healthy normal level of vitamin D, then there is much more vitamin D deficiency in the US than people realize.”
Although exposing onself to the sun boosts one’s vitamin D levels, it also causes cancer, and for this reason, pediatricians and skin doctors advise that parents should make sure their children wear sunblock when they go in the sun. But unfortunately this also stops their skin from making healthy amounts of vitamin D.
Children who are naturally darker skinned need even more sun than fair-skinned children to make healthy amounts of vitamin D.
Mansbach and colleagues found that children taking multivitamin supplements that included vitamin D had the highest overall levels of vitamin D, but this accounted for less than half of all children.
You can also get vitamin D by eating certain foods like liver and fatty fish, but few children in the US eat these foods in enough amounts to make as much vitamin D as they could get from supplements or sunshine, so the researchers recommended that all children take vitamin D supplements, especially those living in high latitudes, where the sun is scarce in the wintertime.
Mansbach said we need to:
“Perform randomized controlled trials to understand if vitamin D actually improves these wide-ranging health outcomes.”
But in the meantime, he said:
“There are a lot of studies demonstrating associations between low levels of vitamin D and poor health. Therefore, we believe many US children would likely benefit from more vitamin D,” he added.
“Serum 25-Hydroxyvitamin D Levels Among US Children Aged 1 to 11 Years: Do Children Need More Vitamin D?”
Jonathan M. Mansbach, Adit A. Ginde, and Carlos A. Camargo, Jr.
Pediatrics, Nov 2009; 124: 1404 – 1410.
DOI:10.1542/peds.2008-2041
Additional sources: Children’s Hospital Boston.
Written by: Catharine Paddock, PhD