Although much more research needs to be done, current evidence has resulted in a shift in recommended practice for the prevention of food allergy in high-risk infants (first degree relative with an allergic condition). Since the primary prevention of allergic conditions is a desirable public health objective, Southwestern Public Health supports and recommends the following position by the Canadian Paediatric Society (CPS):
- Do not restrict maternal diet during pregnancy or lactation. While the evidence that avoiding milk, egg, peanut or other potential allergens during pregnancy and lactation is weak, the risks of maternal undernutrition and potential harm to their infant from avoiding these foods may be significant.
- Breastfeed exclusively for the first six months of life. Health Canada, the CPS, the Dietitians of Canada and the Breastfeeding Committee of Canada have reiterated the manifest health benefits of exclusive breastfeeding for the first six months of life. Whether breastfeeding prevents allergy, however, is not clear. The total duration of breastfeeding (at least 6 months) may be more important for preventing allergic conditions than exclusive breastfeeding, but more research is needed before changes to practice can be recommended.
- For mothers who cannot or choose not to breastfeed, choose a hydrolyzed cow’s milk-based formula. There is some limited evidence that hydrolyzed cow’s milk formula has a preventive effect against atopic dermatitis; extensively hydrolyzed casein formula is likely more effective than partially hydrolyzed whey formula. Amino acid-based formula has not been studied for allergy prevention. There is no role for soy formula in allergy prevention. More evidence is needed to confirm if any infant formula has a protective effect for allergic conditions other than atopic dermatitis.
- Do not delay the introduction of any specific solid food beyond 6 months of age. Delaying the introduction of peanut, fish or egg beyond 6 months has been shown to have no protective effect on allergic sensitization and disease development, and may even increase the risk of developing food allergy.
- Early introduction of specific foods to prevent allergy (before 6 months of age) is currently under investigation but cannot be recommended at this time. Inducing tolerance by introducing solid foods at 4-6 months to prevent food allergies needs to be confirmed in a rigorous prospective trial before it can be recommended.
- Regular, frequent ingestion of newly introduced foods (e.g. several times per week) is important to maintain tolerance. Regardless of the optimal timing for the introduction of solid food, current understanding of immunological tolerance appears to suggest that regular exposures to newly introduced foods help to maintain oral tolerance. However, routine screening for allergy to a food using a skin test or specific IgE blood test without a history of the child ever ingesting the food in question is generally discouraged due to the high risk of false-positive results. For families reluctant to introduce a food because of family history, referral to a certified allergist is recommended. The specialist can decide whether an oral food challenge is warranted.
For further details, go to http://www.cps.ca/en/documents/position/dietary-exposures-and-allergy-prevention-in-high-risk-infants.