During the first year of life, the infant diet is the most powerful determinant of the growth and development of the child. Food allergy is the most common health problem. Many studies show that breast feeding is best and that the feeding of solid foods is best delayed  4 to 6 months to reduce the risk of food allergy. 

Food allergy in infancy is expressed as crying, colic, vomiting, diarrhea, rashes, eczema and cold-like respiratory congestion. Some infants with food allergy become seriously ill and fail to thrive unless their allergy is recognized and corrected.

Infants who develop food allergy in their first year may "outgrow" the first effects but tend to grow into children with more pervasive health, behavior and learning problems unless their diet is properly managed.