Mounting research points toward infancy as a critical period in the development of the immune system and allergic respiratory diseases. For many years, doctors advised allergic parents to keep their young children in pristine, clean environments and avoid high-risk foods such as peanuts, tree nuts and fish until after school age. Now we seem to have shifted in the opposite direction. Articles on the "hygiene hypothesis" (referenced below) discuss how exposure to various bacterial toxins and other germs early on, leads to fewer allergic problems later in life.
A peanut allergy study called "LEAP-study- Learning Early About Peanut Allergy" provided strong evidence for feeding peanuts to high-risk infants, not yet allergic to peanut, in order to prevent the development of peanut allergy.
Now, a report published in Allergy and Asthma Proceedings investigates the relationship between lung function and history of infant breastfeeding in asthmatic children.
Dr. Hwan Soo Kim and associates studied 550 Korean children (age 5-11) who had mild asthma, by performing lung function tests, as well as other breathing tests and blood tests. Parents were given questionnaires which asked about breastfeeding. Based on the answers, children were separated into three groups:
-Breastfed for less than six months
-Breastfed fo more than six months
The breastfed groups were further divided into those who were exclusively breastfed versus partially breastfed (babies also given supplemental formula, other foods or drinks in addition to water).
The results of the study showed that infants breastfed more than six months had better lung function at age 5-11 years compared to those who were not breastfed, or breastfed for a shorter period. The partially breastfed group had less benefit compared to the exclusively breastfed children. Interestingly non-allergic children, exclusively breastfed, had the greatest benefit.
Why is this study important?
Over 25 million people in the U.S. have asthma, which is often diagnosed in early childhood. Missed school and work, associated with asthma flare-ups, places a huge burden on children and parents. Two of the main goals of asthma therapy are to prevent asthma flare-ups and maintain normal lung function (best measured by the pulmonary function test).
There are many attributes in breastfeeding for at least the first four months of infancy.
-It provides infants with several vitamins and nutrients in the form of hormones and other substances which protect against a wide variety of infections.
-The gut of an infant is a delicate reservoir of bacteria some of which are good, and some which are not. Breast milk contains substances that help the infant intestines to develop a healthy proportion of good bacteria.
-Breastfeeding may reduce or delay the incidence of certain allergic diseases such as atopic dermatitis and milk allergy. In fact, breastfed infants are less likely to have wheezing early in life.
Dr. Kim's publication is the first to focus on the benefits of breastfeeding in asthmatic children. The study implicates but doesn't prove that longer periods of breastfeeding during infancy may lead to milder asthma (because of better lung function) later on in life.
More research needs to be done to demonstrate the connection between longer periods of breastfeeding and improved lung function before doctors change their recommendations to parents. But I think doctors are clearly on the right track by encouraging breastfeeding for at least the first 4-6 months of infancy.