Meta-analysisindependent cross-checkfull text checked★ key study I-EGG-101 in-depth review
Giving babies egg early lowers the chance of egg allergy
Timing of Allergenic Food Introduction and Risk of Immunoglobulin E-Mediated Food Allergy: A Systematic Review and Meta-analysis.
Overview
Scarpone R et al.. JAMA Pediatr 2023 · PMID 36972063 · DOI 10.1001/jamapediatrics.2023.0142
In 9 trials, babies who were given egg from 3-6 months were 40% less likely to develop egg allergy (RR 0.60).
Does the study support the specific claim? No · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Test whether early introduction of allergenic foods prevents food allergy.
- How was the study done?
Meta-analysis of randomized trials with GRADE.
- How many people, animals or samples were studied?
23 trials, 13,794 infants; 9 egg trials with 4,811 infants.
- What was actually found?
Early egg introduction reduced egg allergy (RR 0.60, 0.46-0.77; high certainty).
- How large was the observed effect?
About 22 fewer cases per 1000 infants when baseline risk is 5.4%.
- What do the results mean in everyday life?
Keeping eggs away from babies does not protect them from egg allergy; well-cooked egg in the first year is recommended by allergy guidelines.
- What are the study's limitations?
Mostly high-income countries; many families dropped out of multi-food interventions.
- What does it say about Elawady's specific claim?
Contradicts a total egg ban for children.
- Do the results apply to Germany and Europe?
Directly applicable.
- What can explicitly not be concluded from this study?
It cannot show long-term effects on general health in low-income settings.
Scientific in-depth review
1. Full reference
- Authors
- Scarpone R et al.
- Journal
- JAMA Pediatr
- Year
- 2023
- Identifier
- PMID 36972063 DOI 10.1001/jamapediatrics.2023.0142
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
One author reported editorial fees from Cochrane and Wiley and expert-witness fees; no other disclosures (full text). Funding statement not located in the extracted text.
2. Research question
Is the timing of allergenic food introduction in infancy associated with IgE-mediated food allergy at 1-5 years?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis of randomized clinical trials with GRADE (random-effects)
- Population
Infants in 23 trials (13,794 randomized participants); egg analysis: 9 trials, 4,811 participants
- Country
Multinational (trials mainly from high-income countries)
- Period
Databases searched from inception to 29 December 2022
- Sample size
23 trials; 13,794 participants
- Inclusion and exclusion criteria
RCTs evaluating age at introduction of milk, egg, fish, shellfish, tree nuts, wheat, peanut or soya in infancy with IgE-mediated food allergy outcomes at 1-5 years.
4. Methods and endpoints
- Exposure / intervention
Earlier introduction of egg (3-6 months) or multiple allergenic foods (2-12 months)
- Comparator
Later introduction / avoidance
- Endpoints
IgE-mediated food allergy (any food, specific foods); withdrawal from intervention
- Statistical methods
Random-effects risk ratios; GRADE certainty; absolute risk differences for assumed baseline risks
5. Actual results
- Results
Egg introduced at 3-6 months: egg allergy RR 0.60 (95% CI 0.46-0.77; I2 = 0%; 9 trials, 4,811 participants; high certainty). Peanut at 3-10 months: RR 0.31 (0.19-0.51; high certainty). Multiple allergenic foods: food allergy RR 0.49 (0.33-0.74; moderate certainty) but increased withdrawal RR 2.29 (1.45-3.63; I2 89%).
- Absolute risks
Multiple foods: -26 (-34 to -13) food allergy cases per 1000 at 5% incidence (reported). Egg: recalculated ARR 21.6 per 1000 at 5.4% baseline, 3.2 per 1000 at 0.8% (stats/C-EGG-11_early_egg_allergy.py).
- Authors' conclusion
Earlier introduction of multiple allergenic foods in the first year was associated with lower food allergy risk but high withdrawal; earlier egg and peanut introduction probably reduce egg and peanut allergy.
6. Strengths
- Only randomized trials
- GRADE assessment; egg result high certainty with I2 = 0%
- Duplicate data extraction
7. Weaknesses
- Trials mostly from high-income settings
- Adherence and withdrawal problems in multi-food interventions
- No individual participant data analysis
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Comprehensive search, duplicate extraction, GRADE; simplified judgement.
9. Assessment of the statistical interpretation
CI log-symmetric (0.266/0.249). Relative effect is consistent; absolute benefit depends on baseline allergy risk (NNT about 46 at 5.4%, about 312 at 0.8%).
10. Relevance to the specific claim
Shows that withholding egg in infancy is not protective: introducing well-cooked egg early reduces egg allergy. Directly contradicts a blanket egg ban as applied to infants.
11. Independent contrary findings
Authors note that in low- and middle-income settings, where food allergy is uncommon, the broader health effects of early allergen interventions are unclear, and interventions that shorten exclusive breastfeeding may be harmful.
12. Transferability to Germany and Europe
High for Europe; Egypt: egg allergy prevalence data not reviewed, relative effect likely transferable, absolute effect smaller where allergy is rare.
13. Overall methodological judgement
High-quality randomized evidence that early egg introduction lowers egg allergy; it argues against excluding eggs from infant diets.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | low |
| Precision of results | high |
| Directness | indirect |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Optimal form and dose of egg; effect in low-allergy-prevalence populations such as Egypt.
15. Linked fact checks
- Eggs should be completely avoided (all kinds, all cooking methods). – Studies contradicting or limiting the claim
- All eggs (chicken, quail, pigeon, ostrich, etc.) are harmful because an egg is an embryo / contains the 'full components of a living organism'. – Studies contradicting or limiting the claim