What to do to prevent food allergies in infants

"If parents ask how to prevent allergy in their children, our current advice is to introduce the allergenic foods at four to six months of age," write Drs. Elissa Abrams and Allan Becker, Department of Pediatric Allergy and Clinical Immunology, University of Manitoba, Winnipeg, Manitoba. "Once highly allergenic foods are introduced, regular exposure is important for maintenance of tolerance -- children should eat these foods on a regular basis."

Food allergies have increased over time, with an 18% increase between 1997 and 2007 in the United States. A recent survey of Canadian households found that 8% reported at least one food allergy. The most common allergens are cow's milk, soy, peanut, tree nuts, eggs, wheat, fish, shellfish and sesame.

Babies with parents or siblings who have allergies, especially to peanut, are at higher risk of atopy.

A recent randomized controlled trial -- the Learning Early About Peanut (LEAP) study -- found that introducing peanut early, rather than late, in high-risk children reduced the risk of food allergy by as much as 80%. However, children at high risk of peanut allergy may benefit from an allergist's evaluation before peanut introduction.

As a result of the LEAP study, groups such as the American Academy of Allergy, Asthma and Immunology, the American Academy of Pediatrics and the Canadian Society of Allergy and Clinical Immunology, now state that for infants at high risk, there is strong evidence to support the introduction of peanut between 4 and 11 months.

Previous guidelines recommended avoiding potentially allergenic foods until 12 to 36 months of age in babies at high risk. As a consequence, some women avoid potentially allergenic foods during pregnancy and breastfeeding to try to prevent the development of allergies in their babies. However, current guidelines do not support avoidance diets.

To introduce new foods, the American Academy of Allergy, Asthma and Immunology recommends:

1. Introduce a new food every 3 to 5 days in an age-appropriate manner (to avoid choking).

2. Start with grains, yellow and orange vegetables and fruit.

3. Introduce one of the potentially allergenic foods, if well tolerated, in small amounts (e.g., cow's milk, soy, eggs)

4. Introduce highly allergenic foods at home.

5. Increase the quantity of food over several days.

"It has been well documented that avoidance of allergenic foods is not preventive of food allergy," write the authors. "In the newly released LEAP study, there is strong evidence that early introduction of peanut is in fact preventive. How this will change current guidelines on food introduction remains to be seen."