Why your child may need vitamin D supplements

It was a brisk, sunless fall day with early evening fast approaching. The topic was vitamin supplementation, and my pediatric colleague was discussing the merits of dosing children with extra Vitamin D. Neither of us is big on megavitamin supplements for kids who eat well-balanced diets and practice healthy lifestyles, but we agreed that many American kids are just not getting enough of that valuable prehormone, better known as vitamin D.

The American Academy of Pediatrics promotes vitamin D supplementation and has within the last year doubled its recommendation for daily intake of the vitamin. This guideline change ups the recommended minimum vitamin D intake for children from the previous 200 IU/day to the current 400 IU/day. When vitamin D deficiencies are identified, the supplementation should begin within the first few days of a baby's life and extend all the way through the teen years.

The AAP's 2008 clinical report, "Prevention of Rickets and Vitamin D Deficiency in Infants, Children and Adolescents," notes that while there are naturally occurring dietary sources of vitamin D, they are limited to fatty fish and some fish oils, the liver and fats of water mammals, and egg yolks produced by vitamin D-fed chickens.

In addition, while sunlight is known to assist in vitamin D production, its benefits are limited, as dermatologists recommend that childhood sun exposure be discouraged due to ultraviolet light's recognized link with the development of serious skin cancers.

Patients at higher risk for vitamin D deficiency include individuals with darker skin, as increased pigment reduces vitamin D production; inhabitants of cool, northern climates due to their limited sun exposure; and infants who are exclusively breast-fed, since human milk is not fortified. (It's important to note that with proper vitamin D supplementation, the academy still maintains that breast is best and encourages all mothers who are able to do so to continue breast-feeding for at least the first year of a baby's life.)

In the United States, D-prehormone is added to all commercially available infant formulas as well as many milk products, which are then marketed as "vitamin D-fortified." The AAP recommends vitamin D supplements for infants who do not drink 27 to 32 ounces of fortified formula per day, and for older children and adolescents (and adults!) who do not drink at least 32 ounces of vitamin D-fortified milk per day.

AAP experts point out that ensuring appropriate vitamin D and calcium levels during childhood may decrease the risk of developing abnormal bone conditions such as osteoporosis as well as the risk of developing certain systemic diseases such as cancer, diabetes and multiple sclerosis, among others.

Vitamin D status is generally assessed by measuring blood concentrations of 25-hydroxyvitamin D, or 25-OH-D. In adults, vitamin D "deficiency" is defined as 25-OH-D levels of less than 50 nmol/liter, with levels between 50 and 80 nmol/L considered evidence of vitamin D "insufficiency."

While normal lab values have not yet been agreed upon for infants and children, AAP researchers feel that pediatric 25-OH-D levels should reach at least 50 nmol/L. Supplementing a breast-fed infant with the newly recommended 400 IU of vitamin D per day will keep the 25-OH-D blood concentration at greater than 50 nmol/L.

Since it is a fat-soluble vitamin, excess consumption of vitamin D can lead to adverse effects, but doses have to be fairly high to cause toxicity. The National Institutes of Health report currently recognized "tolerable upper intake levels" of vitamin D to be 1,000 IU/day for infants less than 1 year of age, and 2,000 IU/day for older children, adolescents and adults.

• Dr. Helen Minciotti is a mother of five and a pediatrician with a practice in Schaumburg. She formerly chaired the Department of Pediatrics at Northwest Community Hospital in Arlington Heights.