In another example of the critical role that vitamin D plays in human development, it has been demonstrated now that children with low levels of this key nutrient develop allergies.
Vitamin D is relatively difficult to obtain from food (mostly fish) but we make it in our skin when irradiated by sunlight. Skin color variation is directly related to this necessity.
In the past lack of vitamin D in children (or their mothers) has been linked to rickets, incorrect brain development, autoimmune diseases and other immunity related problems. Allergies also fall within the problematic of inappropriate immunity and can well be considered autoimmune diseases, even if often mild and with very specific triggers.
Source: Science Daily.
Ref. Shimi Sharief et al., Vitamin D levels and food and environmental allergies in the United States: Results from the National Health and Nutrition Examination Survey 2005-2006. Journal of Allergy and Clinical Immunology, 2011. Pay per view.