The Rourke Baby Record (RBR), first published in 1985, is a clinical tool for preventive health visits in early childhood (0 to 5 years of age) used by primary care providers across Canada.1–3 Over the years, the RBR recommendations for allergenic food introduction have drastically changed, reflecting the available evidence base. From 1985 to 2011, the RBR recommended that eggs and peanuts be avoided until 12 to 13 months of age (from 2000 to 2011, the recommendation was that egg yolks could be reasonably introduced at 6 months of age). This recommendation was in keeping with the prevailing theory at the time that sensitization occurred through the gastrointestinal tract and that avoidance of allergenic solids allowed for gut maturity.4 The recommendation was supported by observational studies noting an increased risk of atopic disease with solid food introduction at 3 versus 6 months of age and with increased dietary diversity early in life.5,6
However, after the release of these recommendations, which were in keeping with other international recommendations to avoid allergenic solid foods,4 studies emerged supporting early introduction of allergenic solid foods as a means of allergy prevention. As a striking example, a 2010 observational study comparing prevalence of peanut allergy in Jewish school children in the United Kingdom (where peanut introduction was delayed) versus Israel (where peanut was introduced early in infancy and is a staple of the infant diet) demonstrated a 10-fold higher rate of peanut allergy in the United Kingdom (1.85% vs 0.17%; P < .001).7 Several observational studies also noted that early introduction of wheat, egg, and cow’s milk reduced the risk of food allergy.8–10 In addition, a growing body of evidence supported the concept that food allergy is caused by transcutaneous exposure to food allergens in infants with eczema in the absence of ingestion, a concept termed the dual-allergen exposure hypothesis.11 Based on this hypothesis, early ingestion would promote tolerance while delayed ingestion (especially in the presence of eczema, which increases transcutaneous sensitization) might increase the risk of food allergy. Studies have noted that the filaggrin mutation, which is related to skin barrier dysfunction and is present in about half of infants with eczema, is also linked to the development of peanut allergy.12,13
As a result of these developments, a substantial shift in the RBR occurred as of 2014, when delaying the introduction of priority food allergens was no longer recommended for the prevention of food allergies in any infant, including those at risk of atopy.1 After the release of the 2014 RBR, a key randomized controlled trial supported early peanut introduction as a means of peanut allergy prevention in high-risk infants.14 The LEAP (Learning Early About Peanut) study randomized 640 high-risk infants (defined as having severe eczema or egg allergy) into early (4 to 11 months) and delayed (5 years) peanut introduction, and demonstrated a significant reduction in peanut allergy with early introduction (3.2% vs 17.2%; P < .001).14 In addition, a randomized controlled trial of early egg introduction was so successful that it was halted prematurely. The PETIT (Prevention of Egg Allergy with Tiny Amount Intake) study demonstrated in infants with eczema that randomization to early heated egg introduction at 6 months of age versus avoidance until a year of age was associated with a significantly decreased rate of egg allergy (8% vs 38%; P = .0001).15 A 2016 meta-analysis noted moderate-certainty evidence (5 trials; 1915 participants) that early egg introduction (4 to 6 months) was associated with reduced egg allergy (risk ratio of 0.56; 95% CI 0.36 to 0.87) and moderate-certainty evidence (2 trials; 1550 participants) that early peanut introduction (4 to 11 months) was associated with reduced risk of peanut allergy (risk ratio of 0.29; 95% CI 0.11 to 0.74).16 As a result, the statement on and supporting evidence for early introduction of allergenic foods in the 2017 version of the RBR were even stronger: “Delaying the introduction of priority food allergens is not currently recommended to prevent food allergies, including for infants at risk of atopy.”3 Guidelines around the world have also gradually adopted the most recent evidence on the introduction of complementary and allergenic foods (Box 1), including a recent Canadian Paediatric Society practice point recommending introduction of allergenic solids at around 6 months but not before 4 months of age in infants at risk.17
Of note, the recommendations have remained unchanged for breastfeeding mothers, for whom there is no new evidence to support the prevention of childhood allergic disease with maternal dietary restrictions.18
Practicality of early allergenic introduction to infants
The RBR provides practical advice about how to introduce solid foods (including allergenic solids) to infants, which is mirrored by the advice given by the American Academy of Allergy, Asthma & Immunology and the Canadian Paediatric Society.17,19 In general, solid foods should be introduced around 6 months and not before 4 months. It is recommended that iron-containing foods be the first solid initiated, and that caregivers wait about 2 days between introducing new solid foods.20 Once a few complementary foods have been tolerated, allergenic solids can be introduced in an age-appropriate manner to prevent choking (eg, whole nuts should be avoided until 4 years of age). Allergenic solids should be introduced one at a time at home, and if well tolerated, should be consumed regularly (although the optimal frequency is unknown). The Canadian Paediatric Society recommends that allergenic solids, if well tolerated, be ingested a few times a week.
Guidelines, consensus statements, and associated resources for introduction of solid and allergenic foods
Rourke Baby Record
Available from: www.rourkebabyrecord.ca
Canadian Paediatric Society practice point
Summary for clinicians: https://www.cps.ca/en/documents/position/allergenic-solids
Summary for parents and caregivers regarding general introduction of solids: https://www.caringforkids.cps.ca/handouts/feeding_your_baby_in_the_first_year
National Institute of Allergy and Infectious Diseases–sponsored 2017 Expert Panel Guidelines
Available from: https://www.niaid.nih.gov/diseases-conditions/guidelines-clinicians-and-patients-food-allergy
Summary for clinicians: https://www.niaid.nih.gov/sites/default/files/peanut-allergy-prevention-guidelines-clinician-summary.pdf
Summary for parents and caregivers: https://www.niaid.nih.gov/sites/default/files/peanut-allergy-prevention-guidelines-parent-summary.pdf
Instructions for parents and caregivers on feeding peanut protein to infants: https://www.niaid.nih.gov/sites/default/files/addendum_guidelines_peanut_appx_d.pdf
Australian Consensus on Infant Feeding Guidelines 2017 (from the Australasian Society of Clinical Immunology and Allergy, Centre for Food and Allergy Research, National Allergy Strategy, and Australian Infant Feeding Summit Consensus Group)
Available from: https://www.allergy.org.au/hp/papers#p7
Summary for clinicians: https://www.allergy.org.au/images/stories/pospapers/ASCIA_HP_guide_introduction_peanut_infants_2017.pdf
Summary for parents and caregivers: https://www.allergy.org.au/images/pcc/ASCIA_PCC_How_to_introduce_solid_foods_FAQ_2018.pdf
Practical means of peanut introduction are reviewed in depth in the recently released National Institute of Allergy and Infectious Diseases (NIAID) guideline about peanut allergy prevention.21 As a general instruction, it is recommended that the infant is fed a peanut-containing food for the first time when they are healthy and in the presence of an adult who can observe the child for a reaction. Age-appropriate options in infancy include thinned smooth peanut butter (peanut butter mixed with hot water and allowed to cool), smooth peanut butter mixed with pureed fruit, or peanut-containing snacks (eg, Bamba, a dissolvable peanut puff product used in the LEAP trial). Practical physician and parent resources are listed in Box 1. A parent handout with practical tips on introducing allergenic foods is presented in Box 2.17,19
Practical tips to introduce allergenic foods
The following are practical tips for parents to introduce allergenic foods to infants:
Introduce allergenic solids a few weeks before or at around 6 months but not before 4 months of age if the child has eczema or parents and siblings have allergies. Otherwise, start allergenic solids at around 6 months of age
Do not introduce a common allergenic food as the first solid food for an infant. Wait until a few complementary foods have been introduced first
Look for signs that the baby is ready for solid foods before introducing them; these include sitting without support, good control of neck muscles, interest in food, opening the mouth when food is approaching, holding food in the mouth without immediately pushing it out with the tongue, and the ability to turn the head away or lean back when uninterested in food
Introduce allergenic solid foods into the diet one at a time in an age-appropriate way (to prevent choking), with about 2 days between each allergenic solid, at home in the presence of an adult
If the solid is well tolerated, keep it in the infant’s diet—ideally a few times a week for cow’s milk, egg, and nut products. If any reaction is noted, seek medical attention
For egg introduction, use egg products such as hardboiled, scrambled, or steamed egg, all of which can be pureed and mixed with breast milk or boiled water to the desired consistency and cooled before serving
Consider the following as one example of how to prepare a nut product: mix 2 teaspoons of peanut butter with 2 to 3 tablespoons of boiled water, breast milk, pureed fruit, or pureed vegetable (previously tolerated). Adjust to desired consistency and let cool before serving
Ongoing controversies
There is no international guideline consensus on the definition of an infant at high risk of food allergy. While the Canadian Paediatric Society position statement defines an infant at high risk as an infant with a first-degree relative with an allergic condition or an atopic condition such as eczema,17 the NIAID guideline defines an infant at high risk of peanut allergy as an infant with severe eczema or egg allergy.21 High rates of atopy are found in general populations of infants; the Enquiring About Tolerance (EAT) study noted that among 1303 general population infants, 24.3% had eczema and 62.6% had a maternal history of atopy (although severity of atopic conditions might differ among populations at risk).22 As a result, the infants who would most benefit from targeted interventions remain undefined.
There are discrepancies among guidelines about whether allergy testing is required in some infants before peanut ingestion. While no guidelines recommend screening before introduction of any highly allergenic foods other than peanut, the NIAID guideline strongly recommends that infants with severe eczema or egg allergy be evaluated with peanut-specific immunoglobulin E measurement, a skin prick test, or both, before peanut introduction.21 In contrast, the newly released Australian consensus guidelines on infant feeding do not recommend screening before peanut introduction.23 The Canadian Paediatric Society practice point does not mention any indication for preemptive screening either.17
Not all randomized controlled trials have supported early introduction of egg to prevent egg allergy. For those that found a lack of evidence for early introduction, pasteurized raw egg powder was used, which is a highly allergenic and impractical means of feeding egg to an infant.24–27 In addition, the degree of adherence to early allergenic introduction protocols (at 4 months old) remains to be seen—the EAT study, which examined early introduction of 6 allergenic foods at 3 months of age versus 6 months of age, noted poor adherence with very early allergenic introduction (42.8% adhered to the protocol), although early introduction in the EAT study was earlier (3 months) than currently recommended by guidelines for allergy prevention.22
Studies are ongoing and will shed further light on early introduction of allergenic foods. Trials include the PreventADALL (Preventing Atopic Dermatitis and Allergies in Children) study, which is a European populational cohort study examining early introduction of egg, milk, wheat, and peanut by 4 months of age (trial registration number NCT02449850; ClinicalTrials.gov), and the PEAAD (Preventing Peanut Allergy in Atopic Dermatitis) study examining the association between age of peanut introduction and rate of peanut allergy in high-risk infants with eczema.28
Conclusion
As evidence has evolved, so too has the RBR to reflect the best evidence-based recommendations on allergy prevention in the Canadian pediatric population. Future RBR updates will continue to appraise the latest literature to give primary care providers guidance on unresolved controversies, including which infants to preemptively screen for allergies and the optimal timing and frequency of allergenic food introduction.
Acknowledgments
Financial support for the 2017 Rourke Baby Record (RBR) comes from the Government of Ontario and is administered through McMaster University. The licensing fee for electronic medical record use of the RBR (for electronic medical record firms not licensed in Ontario) goes to the Memorial University of Newfoundland Rourke Baby Record Development Fund. No royalties are received for the RBR and there are no honoraria from commercial interests. In-kind support comes from Memorial University and the 3 endorsing organizations: the Canadian Paediatric Society, the College of Family Physicians of Canada, and the Dietitians of Canada.
Footnotes
Competing interests
None declared
The opinions expressed in commentaries are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.
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This article has been peer reviewed.
La traduction en français de cet article se trouve à www.cfp.ca dans la table des matières du numéro de mai 2020 à la page e136.
- Copyright© the College of Family Physicians of Canada
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