A Brazilian study of 6,000 babies from all backgrounds since 1982, finds those who breastfed were more intelligent, spent longer in education and earned more.

Breast milk is best for the baby, and the benefits of breastfeeding extend well beyond basic nutrition. In addition to containing all the vitamins and nutrients the baby needs in the first six months of life, breast milk is packed with disease-fighting substances that protect the baby from illness.

According to a recent major long-term study by doctors* in Brazil, babies are more likely to turn into well-educated and higher earning adults if they are breast-fed for longer.

The researchers followed nearly 6,000 babies from birth for the past three decades, enabling them for the first time to get an idea of the long-term effects of breastfeeding. Nearly 3,500 of them, now 30-year-old adults, accepted an invitation to be interviewed and sit IQ tests for the purpose of the study. Those who had been breastfed proved to be more intelligent, had spent longer at school and earned more than those who had not been.

The question Dr Bernardo Lessa Horta from the Federal University of Pelotas in Brazil wanted to answer was whether breastfeeding translated into greater intelligence and better prospects as an adult. In a recent interview with the BBC, Dr Horta said his study offers a unique insight because in the population he studied, breastfeeding was evenly distributed across social class – not something just practised by the rich and educated.

“Our study provides the first evidence that prolonged breastfeeding not only increases intelligence until at least the age of 30 years but also has an impact both at an individual and societal level by improving educational attainment and earning ability,” he said in an interview with the Guardian.

In analysing their results, now published in the Lancet Global Health Journal they took account of family income at birth, parental schooling, genomic ancestry, maternal smoking during pregnancy, maternal age, birthweight and type of delivery to try to avoid any of those factors skewing the results.

***Bernardo Lessa Horta discusses the association between breastfeeding and intelligence, educational attainment, and income at 30 years of age.

They found that all the breastfed babies had greater intelligence, as measured by a standard IQ test, had spent more years in education and had higher earnings. But the longer they had been breastfed, the greater the benefits. Children who had been breastfed for 12 months had an IQ that was four points higher than those breastfed for less than a month, had nearly a year’s more schooling and earned around $70 a month more – about a third more than the average income level.

Exclusive breastfeeding for the first six months is recommended by the World Health Organisation. Horta said babies who had been breastfed for six months got most of the benefits enjoyed by those who were fed for longer.

According to the Better Health Chanel breastfeeding provides:

  • Enhancement of your bond with your baby
  • Protection for your baby against many common health problems, such as:
        Urinary infections
        Respiratory infections and asthma
        Some childhood cancers
        Diarrhoeal diseases
        Juvenile diabetes
        Childhood obesity
        Sudden unexplained death in infants (SUDI) which includes sudden unexpected death in infants (SIDS)
        Middle-ear infections

Dr Colin Michie, chair of the Royal College of Paediatrics and Child Health’s nutrition committee, said: “It’s widely known that breastfed babies are better protected against chest and ear infections, are at less risk of sudden infant death and are less likely to become obese, but it’s interesting to see the benefits of breastfeeding for a prolonged period of time not only benefit the baby in the early years, but also translate into increased intelligence and improved earning ability later in life.

“It is important to note that breastfeeding is one of many factors that can contribute to a child’s outcomes, however, this study emphasises the need for continued and enhanced breastfeeding promotion so expectant mothers are aware of the benefits of breastfeeding. Furthermore, once mothers have given birth, we must ensure they are properly supported to continue breastfeeding for as long as they are able to.”



*those involved in study: Prof Cesar G Victora, PhD, Dr Bernardo Lessa Horta, PhD, Christian Loret de Mola, PhD, Luciana Quevedo, PhD, Ricardo Tarveres Pinheiro, PhD, Denise P Gigante, PhD, Helen Gonçalves, PhD, Fernando C Barros, PhD