Vitamin D is an essential nutrient for both adults and children. In kids, vitamin D is critical for healthy bone growth and the development of a healthy immune system. Recent research suggests that it may also support other aspects of health in the growing child.  

Vitamin D helps support healthy bone mineralization and calcium homeostasis regulation, and it is essential for the formation of bone during childhood development. Vitamin D also helps support both innate and adaptive immune health. Vitamin D receptors (VDRs) are present on some immune cells including lymphocytes and monocytes. Calcitriol, or 1,25[OH]2D, is a form of vitamin D that has been shown to modulate antimicrobial peptide transcription, the secretion of interleukin (IL)-10, and the production of certain pro-inflammatory cytokines in monocytes and macrophages through VDR signaling. VDR signaling in dendritic cells has also been associated with certain aspects of T-cell differentiation. 

Vitamin D status has been associated with the incidence of microbial illness in the pediatric population. A population study reported that newborns with lower levels of serum calcidiol, or 25[OH]D, had a greater prevalence of otitis media and upper respiratory infections at 3 months of age and wheezing at 15 months. A randomized control trial explored the potential role of supplementation with 1,200 IU of vitamin D during the winter months in the prevention of influenza A. More than 300 children participated. The treatment arm was shown to have a 58% lower likelihood of contracting influenza A as compared to a placebo. 

The incidence of certain autoimmune disorders associated with juvenile onset such as juvenile idiopathic arthritis (JIA) has been associated with serum 25[OH]D deficiencies or insufficiencies. JIA and other autoimmune disorders are associated with an atypical involvement of the immune system and inflammatory mediators. A meta-analysis found vitamin D insufficiencies in 82% of participants with JIA. Vitamin D deficiency has also been associated with a greater incidence of atopic pathologies and certain allergies, including food allergies. 

Deficiencies in vitamin D are common in both pediatric and adult populations. In the pediatric population, they may be a result of inadequate nutritional intake, decreased absorption, darker skin pigmentation, certain pathologies, lifestyle changes, and genetic conditions. Other factors related to vitamin D deficiency include living in higher latitudes and having restricted sun exposure. 

Evidence suggests that supplementation with vitamin D3 can be more effective at raising and maintaining vitamin D levels in the body when compared with vitamin D2 supplementation. Research indicates that supplementation with vitamin D may help promote bone development and a normal immune system in pediatric populations. 

By Colleen Ambrose, ND, MAT