July 31, 2006 — The American College of Asthma, Allergy, & Immunology developed a consensus document for introducing solid foods into an infant's diet to avoid development of food allergies, and they published the new guidelines in the July issue of the Annals of Allergy, Asthma, & Immunology.


Specific recommendations are as follows:

1. During the first 6 months of life, exclusive breast-feeding is recommended, with exclusion of cow's milk formulas and any supplemental foods. Exclusive breast-feeding protects against the onset of allergic symptoms extending far beyond the period of breast-feeding.
2. Complementary feeding of supplemental foods can be introduced starting at the sixth month of life. Introducing supplemental foods during the first 4 months of life has been associated with a higher risk for allergic diseases up to the age of 10 years, which confirms current WHO recommendations.
3. Exposure avoidance is an effective means of preventing cow's milk allergy. By extrapolation, delayed exposure to solid foods should prove to be similarly useful in preventing food allergies.
4. In the developed world, the main foods posing an allergy risk are bovine milk, egg, peanut, tree nuts, fish, and seafood. If introduced early, other foods can become clinically significant allergens. Therefore, it seems reasonable that foods should be introduced individually and gradually.
5. Mixed foods containing a variety of food allergens should not be given unless tolerance to every ingredient has been determined.
6. For processed foods, such as beef and kiwifruit, that are less allergenic when cooked, it is preferred to serve these foods cooked and homogenized.

The consensus statement points out that introducing solid foods is not an ideal research end point because its full benefit depends on the duration of breast-feeding.

Clinical Context

According to the current authors, avoidance of cow's milk and dairy products is a well-known strategy to reduce risk for allergic disease in at-risk infants, but currently, there is no standard schedule for weaning infants who are healthy or at risk for allergy. The WHO defines weaning as the complete cessation of breast-feeding, but a more general definition of "introduction of complementary feeding" is increasingly used.
The current information is a consensus document summarizing evidence-based recommendations for weaning to reduce food allergies based on 52 identified studies.
Study Highlights

• A MEDLINE search was conducted using the terms weaning and infant and allergy, food allergy and sensitization, and dietary prevention and food allergy or allergens from 1980 to 2006.
• Selection criteria were journal impact factor above 1 or scientific society, expert of institutional publication, and appraisable using the WHO categories of evidence.
• Factors for introduction of solids are sufficient macronutrients and micronutrients, toxicologically safe foods, responsive to signals of satiety and hunger, and appropriate for current immune development.
• The American Academy of Pediatrics (AAP) recommendations have not changed for 4 decades.
• The AAP recommends exclusive breast-feeding for 6 months, solid foods in the second half of the first year, continuing breast-feeding up to 12 months or beyond, and infant formula for infants not being breast-fed. Complementary foods should be introduced one at a time during a trial of several days.
• UNICEF and WHO recommend exclusive breast-feeding for 6 months followed by complementary foods while breast-feeding is continued.
• The Dietary Guidelines for Children and Adolescents in Australia recommended pureed foods at 6 to 7 months, gluten-free cereals, and start-up foods followed by vegetable (carrots) and fruit (apple and banana) purees, mashed potatoes, and well-cooked pureed liver and meat. Well-cooked fish, minced liver, and mashed fruits and vegetables are recommended for 8- to 12-month-old children as are egg yolk, cereal, bread, pasta, custard, and yogurt.
• The UK Department of Health recommends that the majority of children should not be given solids before 4 months and cow's milk before 1 year and that the first weaning foods should be nonwheat cereals and pureed fruits and vegetables.
• Observational studies state that the introduction of solid foods before the fourth month increases the risk for atopic dermatitis and cow's milk use before milk letdown increases risk for cow's milk allergy.
• Infants given solid foods at an early age (< 8 weeks) have been shown to have a marginally increased risk for respiratory illness, eczema, and persistent cough.
• Prospective, randomized controlled studies of preterm and full-term infants have shown that 6 months of exclusive breast-feeding lowered asthma and eczema risk in childhood.
• A retrospective study showed that late introduction of egg increased the risk for atopic eczema and wheezing in preschoolers.
• Late introduction to solid foods can postpone but not prevent allergy to some foods, such as fish and lemon.
• Solid food elimination for the first 6 months may be prophylactic for children with family history of atopy.
• An estimate of persistence of the allergy can be drawn from the duration of food allergy. For example, 50% of children lose cow's milk allergy by 1 year of age.
• Observational studies have shown persistence of egg allergy to 35 months in 50% of children, and half the children allergic to eggs will lose the allergy at 4 to 4.5 years.
• 20% of children outgrow peanut allergy, but some may be resensitized.
• Fish allergy is considered a long-lasting condition with few reports of recovery, but no study of the natural history of fish allergy is available.
• Children with milk or egg allergy should avoid other food allergens until at least 3 years old.
• Evidence is lacking for the exact timing of weaning and introduction of specific foods at specific times.
• Recommendations for weaning and allergy avoidance should be customized and sensitization risk, allergy risk, allergy persistence risk, and family history considered.

Pearls for Practice

• Most current guidelines recommend weaning infants to solid foods no earlier than 6 months and providing exclusive breast-feeding for at least 6 months.
• Strategies for avoidance of allergies include breast-feeding for at least 6 months; later introduction of solids; avoidance of allergenic foods, including cow's milk; and recognition of immunologic risk factors.