File photo: Researchers in the US said the study underlines why "breast is best". Picture: AP

London - Breasfeeding protects babies by providing a source of ‘good’ bacteria, research suggests.

Microbes on a mother’s nipple and in her milk are transferred to newborns and help set them up for a lifetime of good health, experts think.

Researchers in the US said the study underlines why "breast is best". The UK has the lowest rates of breastfeeding in the world with fewer than half – 45 percent – still nursing their babies at two months.

In the study, a team from the University of California Los Angeles found that a third of the "friendly" bacteria in a baby’s intestines came directly from milk. About 10 percent originated from the areolar skin – the pigmented area surrounding the nipple.

Scientists say babies who breastfeed even after weaning will continue to reap the benefits as the milk tops up the population of beneficial bacteria associated with better health. Researcher Dr Grace Aldrovandi said: "Our study confirms a bacterial community in breast milk and tracks that community from mothers into the infant gut."

Until now little has been known about the transfer of breast milk microbes from mother to infant. In the study, published in the JAMA Pediatrics journal, scientists examined the DNA of milk and areolar skin from 107 mothers. 

They found breastfeeding infants received almost 28 percent of the bacteria from their mother’s milk, and 10 percent from the skin around the nipple. The remaining 62 percent came from sources the authors could not identify.