Lower vitamin D levels in the breast milk is associated with atopic dermatitis in early infancy

Background Our previous study showed that the discontinuation of breastfeeding could improve atopic dermatitis (AD) symptoms in exclusively breastfed infants. As vitamins A and D are influential on the immune system, we aimed to analyze the association of vitamin A and D levels in breast milk (BM) with AD. Methods We enrolled two‐ to four‐month‐old exclusively breastfed infants. The objective SCORing Atopic Dermatitis (objSCORAD) was evaluated. The lipid layer of BM was extracted and analyzed by liquid chromatography for vitamin A and D levels. Medical charts were reviewed for the clinical course of AD. Results Forty‐five AD patients and 45 healthy controls were enrolled. The objSCORAD was 20.54 ± 1.73 (shown as mean ± SEM) in the AD group. The sex, parental atopy history, nutrient intake of mothers, and vitamin A levels in BM were not significantly different between the two groups. The 25‐(OH) D3 level in BM was significantly lower in the AD group than in the control group (1.72 ± 0.30 and 3.95 ± 0.64 ng/mL, respectively; P = .001). The 25‐(OH) D3 level negatively correlated with objSCORAD (P = .003). The only factor that is significantly associated with persistent AD is the objSCORAD in infancy (P = .003) after adjusting for age, sex, parental atopy history, and 25‐(OH) D3 level by multiple regression. Conclusion Vitamin D levels in BM for exclusively breastfed infants were negatively associated with objSCORAD. Lower vitamin D levels in BM might be a risk factor for infantile AD.