University of Michigan
Department of Pediatrics
Evidence-Based Pediatrics Web Site

Question

• In infants at risk for atopy, does avoidance of solid foods for at least six months when compared with an unrestricted diet lead to lower incidence of allergy in infants?

Clinical Bottom Lines

1. Controversy persists regarding whether dietary avoidance prevents, reduces, or delays food allergy in infants.
2. For infants at risk for atopy, some food allergen avoidance may have the following benefits:
• reduced incidence of food related allergic disorders, such as atopic dermatitis, urticaria, and GI disease; however, this appears to be limited to the first year of life.
• reduced incidence of food specific IgE sensitization, predominantly to milk.
3. Prevalence of allergic rhinitis and asthma were not reduced at 24 months.
4. Specific dietary measures may be most effective, however this study's design precluded their individual or combined identifications.
5. Some dietary interventions are stringent and impractical.

Summary of Key Evidence

1. 379 families were randomized to prophylactic treatment group or control.¹
2. Evaluations were performed after birth, 4 months, 12 months, and 24 months of age.  Assessments included review of infant allergy diaries, thorough history and physical, allergy skin testing, nasal scrapings, serum sampling, and dietary review and education.
3. Parental characteristics between the two groups were similar except for variations in ethnicity, level of education, and serum total IgE (no p values given).  Postpartum smoking differences were significant (2.9% vs. 5.9%, p=0.012).  Drop out rates were significant in the treatment group when compared to control (38% and 13%, p<0.00005).
4. Outcomes examined included: Growth patterns which revealed no significant differences, and postnatal dietary patterns which revealed similar duration of breast feeding and introduction of formula supplementation between groups.  Development of atopic disorders was less frequent in the prophylactic treatment group (16.2% vs. 27.1%, p=0.039); however, there were similar cumulative prevalence by 24 months with no changes in the incidences of asthma of allergic rhinitis. Development of food allergy revealed significant differences at 12 months of food associated urticaria / angioedema (p=0/019), however, these changes were lost by 24 mo. Food skin and RAST testing revealed significant differences in prevalence at 12 and 24 mo of positive skin milk tests in the prophylactic treated group.  Inhalant skin tests are similar in both groups, and the total serum IgE was similar in both groups.  Cord blood IgE and development of atopic disease was also briefly examined.
5. Thus, the NNT to reduce the incidence of atopy at 12 months = 9.  The NNT to reduce all food allergies through 24 months = 8.

Additional Comments

• Decreased incidences of atopic symptoms in the first year of life was also found when comparing infants at risk for atopic disease who were given a prescribed diet to those with a free diet in one non-randomized controlled trial.  It is unclear whether these reductions in the first year of life have future implications for development of allergic diseases.²
• Early feeding is associated with increased incidence of atopic dermatitis, and other adverse health outcomes such as respiratory illness and persistent cough according to one prospective observational study.³
• There is no nutritional advantage from introducing supplemental foods before the age of 4-6 months, and delay beyond 6 months may delay the timely appearance of other developmental milestones.⁴
• A recent meta-analysis showed that exclusive breastfeeding for the first three months of life decreases the incidence of eczema among children with a family history of atopy.⁵
• Additional randomized, controlled, double-blinded studies are needed to clarify this controversy.

Citation

1. Zeiger RS, Heller S, Mellon MH, Forsythe AB, O'Connor RD, Hamburger RN, Schatz M.  Effect of combined maternal and infant food-allergen avoidance of development of atopy in early infancy; a randomized study.  Journal of Allergy & Clinical Immunology 1989; 84(1):72-89.
2. Bardare M, Vaccari A, Allievi E, Brunelli L, Coco F, de Gaspari GC, Flauto U.  Influence of dietary manipulation on incidence of atopic disease in infants at risk.  Annals of Allergy 1993;71(4):366-71.
3. Forsyth JS, Ogston SA, Clark A, Florey CD, Howie PW.  Relation between early introduction of solid food to infants and their weight and illnesses during the first two years of life.  BMJ 1993; 306(6892):1572-6.
4. Committee on Nutrition, American Academy of Pediatrics.  Supplemental Foods for Infants.  Barness LA, ed. Pediatric Nutrition Handbook, Third edition.  Elk Grove Village, IL: AAP, 1993;23-33.
5. Gdalevich M, Mimouni D, David M, Mimouni M. Breast-feeding and the onset of atopic dermatitis in childhood: A systematic review and meta-analysis of prospective studies. J Am Acad Dermatol 2001;45:520-7.

CAT Author: Uptal Patel, MD

CAT Appraisers: John Frohna, MD

Date appraised: April 26, 1999