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STUDY: Benefits of Breast-feeding
JOURNAL: Lancet 2002;359:2003–4
ABSTRACT: Children who were breast-fed during infancy have a reduced risk of becoming obese by age three or four, according to a study published in Lancet (2002;359:2003–4). This new finding adds to the growing list of benefits that have been attributed to breast-feeding, and comes at a time when obesity in both children and adults has reached epidemic proportions in the United States.
COMMENTARY: In the new study, 32,200 Scottish children were observed when they were three to four years old. The prevalence of obesity was 20.8% lower among children who had been breast-fed (7.2%) than among those who had been bottle-fed (9.1%).
When the numbers were adjusted to take into account the effects of birth weight, gender, and socioeconomic status, the risk of obesity was 28% lower in the breast-fed children. It is not known how breast-feeding prevents infants from becoming overweight children, however, as overweight children have an increased risk of becoming obese adults, breast-feeding might help protect against the development of obesity and its complications throughout life.
Obesity has become increasingly prevalent in the United States over the past few decades; by some estimates, more than half of all adults are overweight. Overweight people are at increased risk of suffering from high blood pressure, diabetes, heart disease, gallbladder disease, and osteoarthritis. While lack of physical activity and excessive caloric intake are major factors that contribute to becoming overweight, it is difficult to explain why some people have trouble keeping the weight off.
Some doctors have observed that individuals with food allergies tend to gain weight when they eat the foods to which they are allergic. In those people, avoidance of specific allergens (such as dairy products or wheat) may result in weight reduction that cannot be achieved by other means.
Breast-feeding appears to reduce the risk that someone will develop food allergies. This may be one of the mechanisms whereby breast-feeding helps prevent obesity, although additional research is needed to test that hypothesis.
In addition to reducing the risk of obesity, breast-feeding promotes the development of a healthy immune system.
Children who have been breast-fed have a lower risk of suffering from allergic conditions (such as asthma or eczema), compared with bottle-fed children. In addition, adults who had been breast-fed as infants for more than nine months performed better on intelligence tests, compared with individuals who had been breast-fed for less than nine months or not at all.
The new study adds to the growing body of evidence that human milk is the optimal food for human babies.