For people whose genes put them at risk of becoming obese, exclusive breastfeeding as a baby can help ward off weight gain later in life. These findings from a new study were published recently in PLOS Genetics.
A growing body of research suggests that babies who consume only breastmilk are less likely to be overweight as children or adults, but the reasons behind this and other benefits of breastfeeding are not well understood. The authors investigated whether the weight-reducing impact of breastmilk can counteract the effects of genetic variations that increase the odds that a person will become obese.
In 18-year-old boys whose genes put them in the "high-risk" category for obesity, exclusive breastfeeding until 5 months of age reduced their BMI (Body Mass Index) by 1.14 kg/m2. In girls, the impact was even larger, with a reduction of 1.53 kg/m2.
Breastfeeding exclusively until 3 months of age, or a mix of breastmilk and formula, did not cause the same BMI reduction in high-risk individuals. The World Health Organisation (WHO) recommends that all babies be breastfed exclusively until 6 months of age, but globally, only about 40 percent of babies breastfeed until this age.
The new findings reinforce the WHO's recommendation and suggest that a longer duration of exclusive breastfeeding may have the greatest benefits for individuals with a high risk of obesity.