Scientists have tried to explain how the age old maxim "breast milk is best for the baby" holds true even now.

Jyllian Kemsley, Chemical and Engineering News senior editor, points out that their findings reveal many intriguing and sometimes counterintuitive ways in which sugars, proteins and fat in milk interact with microbes in infants` intestines to nourish babies and protect their health.

For instance, scientists have discovered that breast milk contains oligosaccharides, complex sugars that babies can`t even digest.

It turns out these oligosaccharides, rather than providing nutritional value directly to infants, actually confers protection.

They feed beneficial intestinal bacteria that seem to crowd out harmful E. coli strains that might otherwise thrive.

The findings are published in the Chemical and Engineering News.