Too much vitamin D? Or not enough? Even researchers have trouble sifting through and reconciling all of the conflicting research on the causes of food allergies.
A recent review of multiple studies of vitamin D and allergy sensitization found many conflicting results, but also a strange possible relationship between the two. It is possible that either too little or too much vitamin D exposure prenatally may increase the risk of developing allergies.
Attempts to figure out how pre- and post-natal vitamin D exposure and blood levels are related to developing allergies are made more difficult because vitamin D is now a supplement found in almost all baby food and formula, and is often given as a stand-alone supplement to both babies and expectant mothers.
More research is needed to determine if there is actually a relationship between vitamin D supplements and the increase in food allergies in young children. Vitamin D has been widely available and recommended as a supplement for infants since the early 1990s, about the same time that rates of food allergy began to increase.