3. Food Allergies
According to the American Academy of Allergy, Asthma and Immunology, food allergies affect about 15 million Americans, including an estimated number of about 5.9 million children. About 30% of these children suffer from more than just one food allergy. The most common causes of food allergies include tree nuts, peanuts, shellfish, eggs, and milk. Other causes of food allergies include wheat and soy.