A long-term study is showing a strong link between intelligence and breastfeeding.

A research project took place in Brazil that traced 3,500 babies from all walks of life. The outcome indicated that the babies who were breastfed for longer periods went on in life to score higher on IQ tests as adults.

Although the results were not conclusive, the findings did support current advice that babies should be exclusively breastfed for six months, according to The Daily Star.

This being solid advice, experts still say that mothers should have a choice about whether or not to do it.

The information gained from the research was published in The Lancet Global Health. They stress that there are numerous factors that could have an impact on intelligence, not just breastfeeding alone. But the researchers did try to rule out many of the major influences, such as mother’s education, family income and birth weight.

Dr Bernardo Lessa Horta, from the Federal University of Pelotas in Brazil, said his study provides a unique insight. In the population he studied, breastfeeding was evenly distributed across social class and not something just practiced one or two main groups of people.

Most of the babies, regardless of social class, were breastfed. Some of the babies for less than a month and others past a year.

Those who were breastfed for longer scored higher on measures of intelligence as adults. They were therefore also more likely to earn a higher wage and to have completed more schooling

Dr Horta believes breast milk may offer an advantage because it is a good source of long-chain saturated fatty acids which are essential for brain development.

The study is considered powerful in that it looks at a number of factors including education achievement and income at age 30 across a high sample size.

The researchers noted that although breastfeeding if only one of the many factors contributing to a child’s outcome, the study emphasizes the need for continued and enhanced breastfeeding so expectant mothers are aware of the benefits of breastfeeding.