Michael Wood, MD, Division Chief, Pediatric Endocrinology
Helen DeVos Children's Hospital

An important study to evaluate serum levels of Vitamin D (25(OH)D) in children aged 1 to 11 years was just published in the November issue of Pediatrics.ⁱ It confirms what my colleagues and I have suspected for years: most children have vitamin D levels that are too low. The study found that nearly 20% of children had levels below 20 ng/ml (50 nmol/L), considered a deficiency in adults, and 95% of children had levels below 30 ng/ml (75 nmol/L), which some experts, including the Canadian Pediatric Society, suggest should be the standard in children. The percentage of children with low levels was even higher in those ages 6 to 11 and in non-Hispanic black and Hispanic children.

In my mind, this study highlights an enormous problem.

If you haven't heard, vitamin D has been found to be important in nearly every process in the body. Study after study links low levels to nearly every health condition you can name: cancer, heart disease, hypertension, autoimmune diseases, respiratory and other infectious diseases, diabetes, depression, asthma, even obesity.^{ii, iii, iv, v, vi, vii, viii, ix, x}

While you can't look at most children and tell they have a vitamin D deficiency, we've seen a number of infants in the past several years with hypocalcemic seizures from vitamin D deficiency. Most were exclusively breastfed and did not receive supplemental vitamin D drops. In most cases, the mothers themselves were vitamin D deficient during their pregnancy-one study found that 90% of women in northern climates like ours had insufficient serum levels during pregnancy despite taking prenatal vitamins.^xi Thus, their babies were born already deficient.

The American Academy of Pediatrics changed its recommendation for daily vitamin D intake last year from 200 IU to 400 IU.^xii Many experts, however, suggest that 1,000 IU may be a more appropriate number, particularly for overweight and obese children. This amount is perfectly safe, even for this fat-soluble vitamin. We don't typically see toxicities until children receive at least 10,000 IU daily, possibly higher.^{xiii, xiv}

As community pediatricians and primary care physicians, you have the ability to get the message out to your patients and their parents: Your child needs more vitamin D.  Most children do not consume enough vitamin D in their diets (milk and fortified yogurt) to be safe. Furthermore, since it is difficult for the child's skin in the northern climate to generate enough vitamin D in the fall and winter, supplementation appears to be the best option.

Parents can find liquid supplements for between $10 and $15 for a two-month supply. One supplement that contains vitamin D only (no A or C as in Tri-Vi-Sol) retails for about $12. Gummy and oral supplements for older children cost even less.

 ⁱ Mansbach JM, Ginde AA, Camargo CA. Serum 25-Hydroxyvitamin D Levels Among US Children Aged 1 to 11 Years: Do Children Need More Vitamin D? Pediatrics, 2009; 124(5):1404-10

ⁱⁱ Najada AS, Habashneh MS, Khader M. The frequency of nutritional rickets among hospitalized infants and its relation to respiratory diseases. J Trop Pediatr. 2004 Dec;50(6):364-8.

ⁱⁱⁱ Linday LA, Dolitsky JN, Shindledecker RD. Nutritional supplements as adjunctive therapy for children with chronic/recurrent sinusitis: pilot research. Int J Pediatr Otorhinolaryngol. 2004 Jun;68(6):785-93.

^iv Autoimmun Rev. 2006 Feb;5(2):114-7. Epub 2005. Vitamin D deficiency in systemic lupus erythematosus.

    Kamen DL, Cooper GS, Bouali H, Shaftman SR, Hollis BW, Gilkeson GS.

^v 1: Lancet. 1989 Nov 18;2(8673):1176-8. Lancet. 1990 Jan 13;335(8681):111-2. Serum 25-hydroxyvitamin D and colon cancer: eight-year prospective study. Garland CF, Comstock GW, Garland FC, Helsing KJ, Shaw EK, Gorham ED.

^vi Willer CJ, Dyment DA, Sadovnick AD, et al. Timing of birth and risk of multiple sclerosis: population based study.

BMJ. 2005 Jan 15;330(7483):120.

^vii Holick MF. Vitamin D: important for prevention of osteoporosis, cardiovascular heart disease, type 1 diabetes, autoimmune diseases, and some cancers. South Med J. 2005 Oct;98(10):1024-7. Review.

^viii Lenders CM, Feldman HA, Von Scheven E, et al. Relation of body fat indexes to vitamin D status and deficiency among obese adolescents. Am J Clin Nutr. 2009;90(3):459-467.

^iv Scragg R, Holdaway I, Singh V, et al. Serum 25-hydroxyvitamin D3 levels decreased in impaired glucose tolerance and diabetes mellitus. Diabetes Res Clin Pract. 1995;27(3):181-188.

^v Chiu KC, Chu A, Go VLW, et al. Hypovitaminosis D is associated with insulin resistance and {beta} cell dysfunction. Am J Clin Nutr. 2004;79(5):820-825.

^vi Bodnar LM, Simhan HN, Powers RW, Frank MP, Cooperstein E, Roberts JM.High prevalence of vitamin D insufficiency in black and white pregnant women residing in the northern United States and their neonates. J Nutr. 2007 Feb;137(2):447-52.

^vii Wagner CL, Greer FR, and the Section on Breastfeeding and Committee on Nutrition. Prevention of rickets and vitamin D deficiency in infants, children, and adolescents. Pediatrics 2008;122:1142-1152.

^viii Reinhold V. Vitamin D and Cancer Mini-Symposium: The Risk of Additional Vitamin D. Annals of epidemiology. 2009;19(7):441-445.

^xiv Heaney RP. Vitamin D: criteria for safety and efficacy. Nutr Rev. 2008;66(10 Suppl 2):S178-181.