Babies are less likely to become obese children if they are fed breast milk exclusively, a new study shows.
German scientists say their findings, which were published Friday in the British Medical Journal, are the result of the largest study to date investigating the link between breast-feeding and obesity later in life.
About 60 percent of mothers breast-feed in industrialized countries, but most give up by the time their babies are 2 months old.
The study, which tracked 9,357 children in Bavaria, found that the longer babies were breast-fed exclusively before being switched to formula or food, the lower their chances of starting elementary school as overweight children.
Infants given only breast milk until the age of:
- 1 to 2 months old were 10 percent less likely to be obese
- 3 to 5 months old were more than a third less likely to be obese
- 6 months were 43 percent less likely to be obese
- One year or older were 72 percent less likely to be obese
The study was overseen by Dr. Rudiger von Kries, a professor of pediatrics and adolescent medicine at Ludwig Maximillians University in Munich.
The researchers took into account several factors that could have skewed the results, such as eating habits, socioeconomic class, birth weight, parents' and siblings' ages, how long the children played outside and whether they had their own bedrooms.
In fact, the fatter children were eating less butter, fewer desserts and whole-milk products, and more low-fat dairy foods -- probably in an attempt to lose weight.
"This is one of the highest impact studies I've seen in obesity research in the last year," said Dr. Robert H. Eckel, chairman of the American Heart Association's nutrition committee, who was not connected with the study.
Eckel noted that genetics might be responsible for a small percentage of the cases. However, researcher Von Kries said early analysis of a follow-up study he is conducting that takes into account parents' weight suggests a genetic disadvantage doesn't seem to make much difference.
But is it something in the breast milk, or something associated with the act of breast-feeding that makes a difference?
"We still don't know that, but in the end, I'd be surprised if it wasn't to do with the composition of breast milk," von Kries said.
Eckel noted that part of the phenomenon could be due to bottle-fed babies being "overfed" as mothers try to make children finish each bottle.
Eckel said trying to ward off obesity as early as infancy is important because of the alarming incidence of obesity-related adult diseases now being seen in children, such as adult-onset diabetes.
Weight gain in adolescence, however, is actually a better indicator than childhood obesity of whether someone is more likely to be obese as an adult, he said.
Written By Emma Ross