A new study has found that children who are breast-fed for longer go on to become more intelligent, educated, and successful adults.

Researchers in Pelotas, Brazil looked at 3,500 people, from when they were babies to the age of 30.

Those who were breast-fed for at least a year had a higher IQ - and their earnings were 30% more than those who were bottle-fed. Participants who had been breastfed for longer were also found to have had more years of education.

The results of the survey have been published in The Lancet Global Health. The researchers say that, "our results suggest that breastfeeding not only improves intelligence up to adulthood, but also has an effect at both the individual and societal level, by increasing educational attainment and earning ability."

Bernardo Lessa Horta, one of the study's authors, said, "Perotas is a medium city in southern Brazil, where people do not move a lot. We are able to keep a good follow-up rate of the population. At 30 years old, we were able to follow about 68% of the subjects".

Janet Fyle from England's Royal College of Midwives says breast milk has countless benefits: