By Sue Mah, MHSc, RD
The Canadian Pediatric Society (CPS) recently released a new position statement on the dietary exposures and allergy prevention in high-risk infants.¹ Infants who are at high-risk for developing allergies are defined as usually having a first-degree relative (at least one parent or sibling) with an allergic condition such as a food allergy, atopic dermatitis or asthma.
The CPS position statement aligns with the current thinking in allergy prevention in the United States, Europe and Australia. Here is a summary of the new recommendations.
Do not restrict maternal diet during pregnancy or lactation. There is no evidence that avoiding milk, egg, peanut or other potential allergens during pregnancy helps to prevent allergy, while the risks of maternal undernutrition and potential harm to the infant may be significant. Similarly, maternal diet restrictions during breastfeeding have not proven to prevent allergic conditions in infants, with the possible exception of atopic eczema.
Breastfeed exclusively for the first six months. The total duration of breastfeeding (at least six months) may be more protective than exclusive breastfeeding for six months. Some specialists suggest a compromise: start to introduce solid foods at four months while continuing to breastfeed until the infant is at least six months old. When considering this approach, the infant’s unique atopic risk factors should be weighed against the many benefits of exclusive breastfeeding for six months.
Do not delay the introduction of any specific solid foods beyond six months of age. You may remember some outdated recommendations for delaying the introduction of potential “trigger” foods for infants at high risk of developing allergy (e.g. no cow’s milk protein until age one; no eggs until age two; no peanuts or seafood until age three). New observational evidence suggests that a later introduction of certain foods does not prevent allergy, but may actually increase the risk of developing food allergy.
In fact, there is speculation that a later introduction of peanut may have actually increased the prevalence of peanut allergy. The “dual-allergen-exposure” hypothesis suggests that infants with eczema as an initial risk factor have increased environmental exposure to food topically via “broken” skin, a sensitizing route of exposure. Delaying introduction of the same food doesn’t allow the infant to derive potential benefits from regular oral and gastrointestinal exposure, or to develop tolerance through their regulatory T cell pathways.
Research in the UK is examining the relationship between the age of introduction of peanuts and peanut allergy incidence. In the Learning Early About Peanut (LEAP) prospective allergy study, high-risk infants were randomly assigned to either an early introduction of peanut protein (at four to 10 months of age) or delayed introduction (until three years of age). After the initial introduction to peanut protein, the infants were then exposed to the peanut protein on an ongoing basis of three times per week because the regular consumption of a potentially allergenic food may be as important as when that food is first introduced. When the study cohort reaches five year of age, researchers will evaluate the presence or absence of peanut allergy.
Source: Canadian Pediatric Society
¹ Canadian Pediatric Society, http://www.cps.ca/documents/position/dietary-exposures-and-allergy-prevention-in-high-risk-infants