January 8, 2008 — The American Academy of Pediatrics (AAP) has issued an updated policy statement that reviews the nutritional options during pregnancy, lactation, and the first year of life that may or may not affect the development of atopic disease. The new recommendations, which discuss the role of maternal dietary restriction, breast-feeding, timing of introduction of complementary foods, and hydrolyzed formulas, are published in the January issue of Pediatrics.

"This clinical report reviews the nutritional options during pregnancy, lactation, and the first year of life that may affect the development of atopic disease (atopic dermatitis, asthma, food allergy) in early life," write Frank R. Greer, MD, and colleagues from the AAP Committee on Nutrition and Section on Allergy and Immunology. "It replaces an earlier policy statement from the American Academy of Pediatrics that addressed the use of hypoallergenic infant formulas and included provisional recommendations for dietary management for the prevention of atopic disease. The documented benefits of nutritional intervention that may prevent or delay the onset of atopic disease are largely limited to infants at high risk of developing allergy (ie, infants with at least 1 first-degree relative [parent or sibling] with allergic disease)."

The evidence reviewed does not support a major role for maternal dietary restrictions during pregnancy or lactation. However, breast-feeding for at least 4 months vs feeding formula made with intact cow's milk protein seems to prevent or delay development of atopic dermatitis, cow's milk allergy, and wheezing in early childhood.

Studies of infants who are at high risk for atopy and who are not exclusively breast-fed for 4 to 6 months offer modest evidence suggesting that use of hydrolyzed formulas may delay or prevent the onset of atopic disease vs formula made with intact cow's milk protein. This especially seems to be the case for atopic dermatitis. However, not all hydrolyzed formulas protect to the same extent, based on comparative studies.

"There is also little evidence that delaying the timing of the introduction of complementary foods beyond 4 to 6 months of age prevents the occurrence of atopic disease," the study authors write. "At present, there are insufficient data to document a protective effect of any dietary intervention beyond 4 to 6 months of age for the development of atopic disease." The study authors then summarize, "It is evident that inadequate study design and/or a paucity of data currently limit the ability to draw firm conclusions about certain aspects of atopy prevention through dietary interventions."

Bearing in mind these limitations, the study authors make the following recommendations:

• Currently, there is no evidence that maternal dietary restrictions during pregnancy play a significant role in preventing atopic disease in infants. Except possibly for atopic eczema, avoidance of antigens during lactation does not seem to prevent atopic disease, although available data are scanty at best.
• For infants at high risk for development of atopic disease, available evidence supports that exclusive breast-feeding for at least 4 months vs feeding intact cow's milk protein formula decreases the cumulative incidence of atopic dermatitis and cow's milk allergy in the infant's first 2 years of life.
• Available evidence supports that exclusive breast-feeding for at least 3 months protects against wheezing in the child's early life, but in infants at risk of developing atopic disease, available evidence is not convincing that exclusive breast-feeding protects against allergic asthma in children after 6 years of age.
• Based on studies of infants at high risk of developing atopic disease who are not breast-fed exclusively for 4 to 6 months or who are formula fed, evidence is modest that use of extensively or partially hydrolyzed formulas vs cow's milk formula may delay or prevent early childhood atopic dermatitis. Not all hydrolyzed formulas have the same protective benefit; extensively hydrolyzed formulas may help prevent atopic disease to a greater extent than partially hydrolyzed formulas.
• More studies are needed to elucidate whether these benefits persist into late childhood and adolescence. Any decision-making process regarding use of hydrolyzed formulas must consider their higher cost. Use of amino acid–based formulas to prevent atopy has not yet been studied.
• To date, no convincing evidence supports the use of soy-based infant formula to prevent allergy.
• Solid foods should not be introduced before the infant is 4 to 6 months old. However, evidence to date is unconvincing that delaying their introduction beyond that time frame significantly helps prevent the development of atopic disease, regardless of whether infants are fed cow's milk protein formula or human milk. This recommendation also applies to foods thought to be highly allergic, such as fish, eggs, and foods containing peanut protein.
• In infants 4 to 6 months of age, data are insufficient to support a protective effect of any dietary intervention for the development of atopic disease.

"Additional studies are needed to document the long-term effect of dietary interventions in infancy to prevent atopic disease, especially in children older than 4 years and in adults," the study authors conclude. "This document describes means to prevent or delay atopic diseases through dietary changes. For a child who has developed an atopic disease that may be precipitated or exacerbated by ingested proteins (via human milk, infant formula, or specific complementary foods), treatment may require specific identification and restriction of causal food proteins."

Pediatrics. 2008;121:183-191.

Clinical Context

Study Highlights

• There is not enough evidence to recommend dietary restrictions among pregnant women with the goal of reducing atopic disease in their children. Although dietary food allergens can be detected in breast milk, there is insufficient evidence to recommend exclusion diets among lactating mothers.
• Breast-feeding for 3 months has been demonstrated to reduce the risk for incident atopic dermatitis among children by 32% vs formula feeding. This effect is most prominent among children with a family history of allergy. The authors recommend exclusive breast-feeding for at least 4 months to reduce the risk for atopic dermatitis in their children.
• Exclusive breast-feeding for at least the first 4 months of the infant's life can also reduce the risk for incident cow's milk allergy during the first 2 years of childhood.
• Exclusive breast-feeding during infancy may actually increase the risk of developing asthma, particularly among children with a family history of asthma. Conversely, breast-feeding may reduce the frequency of wheezing episodes among children younger than 4 years.
• There is no evidence that hydrolyzed formulas are superior to human milk in preventing atopic disease.
• Hydrolyzed formulas may delay or prevent atopic dermatitis vs cow's milk formula, but not all hydrolyzed formulas provide the same degree of benefit. In particular, extensively hydrolyzed formulas may be beneficial in this outcome.
• Soy formulas should not be recommended for the prevention of atopic disease. Amino acid–based formulas have not been extensively studied in the prevention of atopic disease.
• Previous research suggested that delaying the introduction of solid foods can reduce the risk for atopic disease, but more recent, methodologically sound trials have not been supportive of the delayed introduction of complementary foods. The current report recommends that solid foods not be introduced before the infant is 4 to 6 months old, but there is insufficient evidence to recommend further delay in the introduction of complementary foods, regardless of whether infants are fed formula or human milk. Also, there is insufficient evidence to recommend the withholding of foods considered to be highly allergenic, including fish, eggs, and foods containing peanut protein.
• No significant data support any dietary intervention for infants 4 to 6 months old to prevent atopic disease.
• More research is necessary to study the long-term effects of early dietary interventions to prevent atopic disease during later childhood and adulthood.

Pearls for Practice

• Previous research has suggested that the prevalence of asthma, eczema, and hay fever has increased among younger and older children.
• The current clinical report suggests that breast-feeding during the first 4 months of life reduces the risk for atopic dermatitis vs alimentation with cow's milk formula. However, many other dietary interventions during early life do not seem to have a profound effect in reducing the risk for atopic disease.

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