Breast is best
Two separate international studies released this week advocate breastfeeding longer - to increase the child's intelligence and boost its resistance to respiratory illnesses.
"Both studies are quite on the mark in terms of other research that has been done," said Ms Jenni James, a midwife lactation consultant at Royal Women's Hospital in Melbourne. "It's good research by the look of it, with big numbers of subjects."
In the first of the studies, released today in the Journal of the American Medical Association, researchers have shown a link between the duration of breastfeeding and intelligence in young adults.
The work, undertaken by researchers at the Danish Epidemiology Science Centre in Copenhagen and The Kinsey Institute at Indiana University, used data on participants from the Copenhagen Perinatal Cohort which is made up of people who were born between October 1959 and December 1961.
The researchers looked at data about the participants including the results of intelligence tests they had taken. 973 men with a mean age of 18.7 years had sat the Borge Priens Prove (BBP) test, and 2,280 men and women with a mean age of 27.2 years had sat the Wechsler Adult Intelligence Scale (WAIS).
The researchers allowed for social, economic, and health factors in the parents, and found that a significant positive association existed between the duration of breastfeeding and intelligence. In the participants who sat the WAIS, the IQs were 99.4 for those breastfed less than one month, 101.7 (two to three months), 102.3 (four to six months), 106.0 (seven to nine months) and 104 (more than nine months).
The researchers make suggestions for the observed positive association between breastfeeding and cognitive development, including the suggestion that breast milk may contain nutrients not found in cow's milk or formula and the physical and psychological contact between mother and child during feedings.
Breast is good for the chest
In a separate American study, researchers have demonstrated that an additional two months of breastfeeding (totalling six months) substantially increases an infant's protection against pneumonia and recurrent ear infections.
The research was an analysis of a nationally representative, cross-sectional survey of 2,277 children between the ages of 6 and 24 months. The children were split into various categories depending on how long they had been breastfed for.
The researchers looked at the percentage of children in each group who experienced pneumonia, wheezing and recurrent colds and ear infections.
By allowing for social and environmental factors, the researchers were able to establish that children who were fully breastfed for six months had significantly lower risk for respiratory infections in the first two years. The chance of contracting pneumonia was reduced five fold, and the risk of recurrent ear infection was half as likely.
The work was undertaken by investigators at UC Davis Children's Hospital, the University of Rochester and the American Academy of Paediatrics. The findings were presented at the joint meeting of the 2002 Paediatric Academic Societies and American Academy of Paediatrics in Baltimore.
The World Health Organization last year extended their recommended exclusive breastfeeding period to six months. "The majority of full term healthy babies don't need anything but breast milk for the first six months," said Ms James.
At 80 per cent take-up, Australia has one of the highest breastfeeding initiation rates in the world. There is a high dropout rate at the six to 12 week mark which is often because of problems that are not addressed, according to Ms James. The next drop off times are at six months and nine months - usually the result of the mothers returning to work.
"Ideally babies are breastfed until they are two years old," recommended Ms James.