Published Online: November 26, 2012
Even though the timing of infant feeding has proven to be important in preventing a number of childhood diseases and for optimal growth, its role in the prevention of childhood allergies is inconclusive. Despite this insufficient evidence, expert bodies, including the American Academy of Pediatrics, the European Society for Pediatric Gastroenterology, Hepatology and Nutrition, and the Australian Society of Clinical Immunology and Allergy, all recommend that for the prevention of allergic diseases, the child should be exclusively breastfed for the first 4-6 months of life, thereafter complementary foods can be introduced. In recent times several studies have examined whether these recommendations are optimal and are supported by strong scientific evidence. The findings from the majority of these studies have largely indicated that delaying the introduction of complementary foods up to 4 to 6 months seems not to prevent the occurrence of allergies. Although these findings have come only from observational studies, the ethical dilemma in randomizing breastfeeding has made it impossible to confirm the results in a randomized controlled trial, which is currently the gold standard in guiding effective clinical decisions. Consequently, well-designed observational epidemiological studies remain the primary source to address the question of whether the timing of infant feeding may play any preventive role in the development of childhood asthma and allergies.
In a recent study published in The Journal of Allergy and Clinical Immunology (JACI), Nwaru et al investigated whether the duration of breastfeeding and the age when complementary foods are introduced may influence the risk of asthma and allergic symptoms among 5-year-old Finnish children who were recruited at birth. On a form parents recorded the age of the child when each complementary food was added to the diet. The form was kept at home and continuously completed as new foods were introduced to the child until the age of two years. When the children were 5 years of age, the parents also completed the International Study of Allergies and Asthma in Childhood (ISAAC) questionnaire for the assessment of the development of asthma and allergic symptoms. Blood samples were also collected from the children to assess allergic antibodies.
The authors did not see any association between the duration of exclusive breastfeeding and the development of asthma and allergic symptoms. However, they observed that children who were breastfed for less than 9.5 months compared to those with longer breastfeeding had almost three-fold risk of developing asthma, particularly non-atopic asthma, by 5 years of age. The authors also found that children who received cereals (oats, wheat, rye, barley) before 5 months, fish before 6 months, and egg before 8 months as complementary foods were at a decreased risk of developing asthma and allergic symptoms by the age of 5 years. The authors concluded that these results indicate that while the duration of exclusive breastfeeding seems not to play any role in the development of asthma and allergic diseases, introducing complementary foods early (at most by 5 months) while continuing breastfeeding may be beneficial for the prevention of childhood asthma and allergies. They suggested that by virtue of their findings, and in line with other recent evidence, current recommendations on the timing of infant feeding for the prevention of asthma and allergies in children may require further attention.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.