In cases where expectant mothers were found to have a low vitamin D level in the blood, the occurrence of food allergies among their two-year old children was rarer than in cases where expectant mothers had a high vitamin D blood level. In reverse, this means that a high vitamin D level in pregnant women is associated with a higher risk of their children to develop a food allergy during infancy. Furthermore, those children were found to have a high level of the specific immunoglobulin E to food allergens such as egg white, milk protein, wheat flour, peanuts or soy beans.
Apart from diet, the level of vitamin D is mainly affected by conditions such as season, exposure to the sun and the amount of time spent outdoors — these factors were also taken into account in the current risk analyses of vitamin D and food allergy. Even though the occurrence of food allergies is undoubtedly affected by many other factors than just the vitamin D level, it is still important to take this aspect into consideration. It is advisable for pregnant women not to take vitamin D supplements. and excess of vitamin D can increase the risk of children developing a food allergy in the first two years of their life.