THE DETAILS: Dr. Mansbach and colleagues analyzed data (which they drew from the National Health and Nutrition Examination Survey) from what they deemed a “nationally representative sample” of U.S. children between the ages of 1 and 11 to estimate vitamin D levels for American children as a whole. Based on their analysis, the study authors concluded that 6.3 million children ages 1 to 11 in the U.S. (or, nearly 20 percent of all children in that age group) don’t meet the American Academy of Pediatrics' minimal level of 50 nmol/L blood levels. Optimal vitamin D levels in children haven’t yet been determined, and, in fact, there’s controversy even over what level of vitamin D should be considered deficient. But the data also showed that 24 million children ages 1 to 11 in the U.S. (approximately two-thirds of all children in that age-group) have levels below a more generous threshold of 75 nmol/L—including 92 percent of non-Hispanic black children, 80 percent of Hispanic children, and 59 percent of white children.
WHAT IT MEANS: "On the basis of our nationally representative sample of U.S. children ages 1 to 11, we know now that there are millions of children with levels of vitamin D lower than some experts believe to be healthy," says Dr. Mansbach—"especially among non-Hispanic black and Mexican American children," whom the study authors speculate don’t generate as much vitamin D through sunlight exposure as fairer-skinned children because increased skin pigmentation reduces vitamin D generation.
What that means: Vitamin D is essential for strong bones—and American children aren’t getting enough. Beyond that, however, higher levels of vitamin D have been shown in some studies, note the study authors, to improve not only bone health but also to prevent cancer, autoimmune diseases, type 1 diabetes, infectious diseases, heart attacks, and childhood wheezing, as well. And, again, U.S. kids aren’t getting high enough levels for those effects. Not even close.
Here’s how to make sure your child has ample vitamin D—and the health benefits that come with it:
• Supplement. Since few foods contain natural vitamin D, the best way to make sure your child gets enough is through supplements. "The American Academy of Pediatrics recommends 400 International Units (I.U.) of vitamin D a day—the amount in most multivitamins formulated for children," says Dr. Mansbach. He also suggests speaking to your pediatrician about the appropriate level for your particular child, since it’s unclear whether 400 I.U. is quite enough. For instance, if your child is non-Hispanic black or Mexican American—the population in the study that had the lowest levels of vitamin D—or you live in a colder climate with little sunlight, you may need to consider giving 800 I.U. per day—but only under your doctor’s supervision. "You cannot simply double up on your multivitamin supplement, since that would provide too much of some of the other vitamins and minerals," says Dr. Mansbach.
• Get them in the sun—but cautiously. Sunlight—specifically ultraviolet B (UVB) rays—naturally generates vitamin D in the body. For that reason, and also to help them get some exercise, make sure your children log off the computer and head out into the sun for even small periods of time every day. “Although I don’t have data, my sense is that we’ve become very much of an indoor society,” says Dr. Mansbach. "Summer sunlight exposure is the major source of vitamin D for most people. However, sunlight exposure is problematic as a cure for vitamin D deficiency, since it can cause sunburns and eventually lead to skin cancer."