New research says breastfeeding does not protect children against developing asthma or allergies.
The researchers from McGill University in Canada say babies who live on breast milk solely or for a long time do not have a lower risk of developing allergies or asthma compared to a baby who is not breast fed.
Breastfeeding has been a hotly debated issue in the last decade and whether it protects from asthma and/or allergies is a controversial subject; the researchers say to date the only evidence has been based on observational studies.
For their study the researchers recruited 17,046 breastfeeding mothers who attended 31 maternity hospitals attached to polyclinics in Belarus during the 1990s.
The mothers were divided into two groups, one group was encouraged to breastfeed, while in the other, the control group, were not.
At the three month stage the number of mothers breastfeeding in the first group had increased substantially compared to the control group and these mothers continued breastfeeding for much longer.
A follow up 6.5 years later of 13,889 children included testing for symptoms of allergies and/or asthma.
The testing was carried out between December 2002 and April 2005 and a questionnaire was used to garner information on the diagnoses of eczema, hay fever and asthma.
The children also underwent prick tests to measure their sensitivity to house dust mites, birch pollen, mold, cats, and mixed northern grass.
The scientists found that breastfeeding does not provide any protection against asthma or allergies.
The authors say the results underline the importance of finding other explanations for the recent epidemic of allergy and asthma.
The study was led by Dr. Michael Kramer from McGill University and funded by the Canadian Institutes of Health Research (CIHR).
Dr. Kramer says Belarus has much lower rates of allergy and asthma than places like Canada and there's considerable debate as to why that is.
Dr. Kramer says the benefits of breastfeeding were a reduction in gastrointestinal infections and atopic eczema for the first year of life and he urges mothers to continue to breastfeed.
He says the results are similar to those found in studies in New Zealand, where allergy and asthma are even more common than they are in Canada which suggests that there is nothing unusual about the setting which might offer an explanation.
The research is published in the British Medical Journal (BMJ).