The study, spearheaded by Dr. Dror Mandel of Tel Aviv University in Israel, is the first to look at the nutritional value of breast milk after prolonged nursing.
Mandel and colleagues compared milk from 27 women who had been actively nursing for two to six months, and 34 mothers who had been nursing for 12 to 39 months.
In the journal Pediatrics
A liter of milk from women breastfeeding for a shorter period of time contained 740 calories, while the milk in women breastfeeding for a year or longer contained 880 calories.
Currently, the American Academy of Pediatrics recommends mothers breastfeed their infants for six months, but say nursing the baby for a year or more will give the child the full benefits of nursing, which include cutting the rates of illnesses like ear infections and diarrhea, and reducing the risk of childhood obesity.
Mandel and colleagues noted the ideal duration of breastfeeding is unknown.
