New Guidelines for Introducing Solid Foods to Avoid
Development of Infant Allergies CME
News Author: Laurie Barclay, MD
CME Author: Désirée Lie, MD, MSEd
Disclosures
To earn CME credit, read the news brief along with the CME information that follows and answer the test
questions.
Release Date: July 31, 2006; Valid for credit through July 31, 2007
Credits Available
Physicians - maximum of 0.25 AMA PRA Category 1 Credit(s)™ for physicians;
Family Physicians - up to 0.25 AAFP Prescribed credit(s) for physicians
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.
"Whereas parents and pediatricians can be in no doubt regarding the avoidance of cow's milk
and dairy products as complementary foods for the primary prevention of allergic disease in
at-risk infants, the same degree of confidence cannot be shared regarding the introduction of
the child to a solid diet, for which no evidence- or consensus-based guidance is available,"
write Alessandro Fiocchi, MD, from the University of Milan Medical School in Italy, and
colleagues from the Adverse Reactions to Foods Committee of the American College of
Allergy, Asthma, and Immunology. "To compound the problem, there is no standard schedule
for weaning infants who are healthy or at risk for allergy."
The objective of this consensus document was to make recommendations based on a critical
review of the evidence for the timing of the introduction of solid foods and its possible role in
the development of food allergy. Based on their clinical experience and research expertise,
the authors retrieved 52 studies from MEDLINE searches that satisfied the following
conditions: English language, journal impact factor above 1 or scientific society, expert, or
institutional publication, and appraisable using the World Health Organization (WHO)
categories of evidence.
A review of these studies suggested that early introduction of solid foods can increase the risk
for food allergy, that avoidance of solids can prevent the development of specific food
allergies, that some foods are more allergenic than others, and that some food allergies are
more persistent than others.
The consensus statement recommends that pediatricians and allergists should cautiously
individualize the introduction of solids into the infants' diet. For infants at high risk for allergy,
the optimal age for the introduction of selected supplemental foods should be 6 months; 12
months for dairy products; 24 months for hen's egg, and at least 36 months for peanut, tree
nuts, fish, and seafood.
"For all infants, complementary feeding can be introduced from the sixth month, and egg,
peanut, tree nuts, fish, and seafood introduction require caution," the authors write. "Foods
should be introduced one at a time in small amounts. Mixed foods containing various food
allergens should not be given unless tolerance to every ingredient has been assessed."
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 breastfeeding 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.
"Devising a timetable leading to the definition and minimization of clinical risk in a defined
population of likely candidates remains among the achievable goals of food allergy
prevention," the authors conclude. "Faced with a parent asking 'which food' and 'when,' the
pediatrician has to integrate a reasonable schedule for the introduction of solid foods based
on biochemical, immunologic, and epidemiologic data. Choosing the food to be introduced
depends on its 'allergenicity index,' which depends on several factors: (1) sensitization risk
(how many children become sensitized to that food when exposed), (2) allergy risk (how
many children sensitized to that food develop clinically relevant symptoms), (3) allergy
persistence risk (the half-life of a diagnosis of allergy), and (4) personal risk (familial
recurrence of allergic diseases)."
The authors have disclosed no relevant financial relationships. This feature is supported by
an unrestricted educational grant from AstraZeneca LP.
Ann Allergy Asthma Immunol. 2006;97:10-21.
Learning Objectives for This Educational Activity
Upon completion of this activity, participants will be able to:
1. Summarize current recommendations for weaning infants.
2. Describe strategies to minimize food allergies among children.
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
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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 wellcooked 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.
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Recommendations for weaning and allergy avoidance should be customized and
sensitization risk, allergy risk, allergy persistence risk, and family history considered.
Pearls for Practice
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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.