According to the European Food Information Council, the prevalence of food allergies during the first three years of life fluctuates between 3 and 7 percent. This is related to the early introduction of milk formulas, as well as solid foods, to the child’s diet. Even though it is hard to completely prevent this problem, especially in children who have family history of allergies, there are some strategies that can help to delay the development of food allergies or reduce their intensity.
The main action to prevent food allergies is to delay the introduction of foods with a high allergenic potential (that is, the foods that are more likely to cause an allergic response), such as: milk, egg whites, fish, soy, citric fruits, nuts, and wheat. The recommendation of the World Health Organization (WHO) is to provide exclusively breast milk (which means only this milk and no other kind of liquid or food) during the first six months of life and then start with complementary foods (semi-solid or solid foods) thereafter. Several studies have shown a possible protective role of human milk when provided exclusively, as indicated by the WHO, reducing the incidence of food allergies. This can be explained by the fact that human milk contains substances that are beneficial to the immune system, which help the body’s defense mechanisms. 
The correct way of introducing foods is to do so one at a time. For example, if it is the first time you are giving potatoes to your baby, wait at least three days before offering another new food. This will help you detect any abnormal response very quickly and easily. If infants are offered various new foods at the same time, it will be more difficult to identify which ones they tolerate well and and which ones they don't. Examples of signs/symptoms of an allergic reaction include: skin irritation, vomiting, or diarrhea. If you notice any of these reactions, it is important for you to consult with your pediatrician, because you may have to eliminate that food from your child's diet, at least for some time.
The reason to be so careful is because the digestive tract of the baby is still immature at this stage of life. It isn't until the first year of age that a baby is expected to be on a complete diet, which includes most family foods.
For children with a family history of allergies, the AAP recommends refraining from introducing these allergenic foods into the child's diet until he or she reaches the following ages:
- Cow’s milk and other dairy foods (age 12 months)
- Egg and egg-containing foods (age 24 months)
- Fish and shellfish (age 36 months)
Even though it is not possible to prevent food allergies in children in 100% of the cases with a known predisposition, we can reduce the risk or the intensity of the problem. Therefore, it is worth considering these recommendations, and don’t forget to have your infant closely monitored by a pediatrician or dietitian.
Sources:
European Food Information Counceil (2006). "Food Allergies and Intolerances". Retrieved on August, 2008 from http://www.eufic.org/article/es/page/BARCHIVE/expid/basics-alergias-intolerancias-alimentarias/ .
American Academy of Allergy, Asthma & Immunology. "Food Allergies and Reactions" Fact Sheet. Retrieved on August , 2008 from http://www.aaaai.org.
The Panamerican Health Organization / The World Health Organization (2003). “Principios de orientación para la alimentación complementaria del niño amamantado.” Retrieved on August, 2008 from http://whqlibdoc.who.int/paho/2003/9275324603_spa.pdf.
