PURPOSE:

• Ierodiakonou et al. (JAMA, 2016) synthesized previous research to determine the influence of the timing of introduction of allergenic foods into the infant diet and risk of allergic and autoimmune disorders

METHODS:

• Systematic review and meta-analysis
• Intervention and observational studies that assessed introduction of allergenic food in the first year of life
• Allergenic foods included
  • Milk, egg, fish, shellfish, tree nuts, wheat, peanuts and soya
• Primary outcomes
  • Wheeze, eczema, allergic rhinitis, food allergy, allergic sensitization, type 1 diabetes mellitus, celiac disease, inflammatory bowel disease, autoimmune thyroid disease, and juvenile rheumatoid arthritis

RESULTS:

• 24 intervention trials evaluated allergic outcomes in 13,298 participants and 5 intervention trials assessed autoimmune diseases in 5623 participants
• 9 observational studies reported allergic outcomes in 142,103 participants and 48 observational studies evaluated autoimmune diseases in 63,576 participants
• Peanut introduction at age 4 to 11 months was associated with
  • lower risk of peanut allergy (risk ratio [RR], 0.29; 95% CI, 0.11-0.74; P = .009)
• Egg introduction (from 4-6 months) based on moderate-certainty evidence was associated with
  • Lower risk of egg allergy (RR, 0.56; 95% CI, 0.36-0.87; P = .009)
• Fish introduction (before 6-9 months) based on low- to very low-certainty evidence was associated with reduced allergic sensitization and rhinitis
• Gluten introduction was not associated with risk of celiac disease based on high-certainty evidence
• Risk reductions not seen for other allergenic foods including cow’s milk

CONCLUSION:

• This study demonstrated early peanut and egg introduction appears to be associated with lower risk of allergy
• The data suggests that in humans, oral tolerance appears to be antigen specific (i.e. introduction of peanuts doesn’t protect against egg allergy)
• Authors suggest that a possible mechanism for early introduction of fish in reducing allergic sensitization are the effects of anti-inflammatory omega-3 polyunsaturated fatty acids found in fish

Learn More – Primary Sources:

Timing of Allergenic Food Introduction to the Infant Diet and Risk of Allergic or Autoimmune Disease: A Systematic Review and Meta-analysis

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