Although two randomized controlled trials (RCTs) [12,13] and a recent Cochrane meta-analysis of RCTs for asthma [14] showed a role for vitamin D supplementation in the reduction of atopic exacerbations, other recent data do not support the benefits of vitamin D supplementation for asthma [12,13,15,16], atopic dermatitis, or IgE levels [17–19]. This evidence concerns the gene IGHE and atopic eczema.