Breastfeeding fails to protect babies against everything

It is well known that breastfeeding has a positive impact on the general health of a baby, but there has been a lot of debate concerning its effects on asthma, eczema and allergies. While some studies have found breastfeeding to have a protective effect against asthma and allergies, other studies have produced contradictory results that suggest it increases the risk.

Researchers from Uppsala University collected self-reported data from over 330,000 middle-aged people in the UK, the largest study of its kind to date, and concluded that there may be a negative correlation between breastfeeding and eczema and allergies.

“Our study shows that individuals that were breastfed as babies have an increased risk of developing hay fever and eczema, while breastfeeding doesn’t seem to have an effect on asthma,” said Weronica Ek, study lead and researcher at the Department of Immunology, Genetics and Pathology.

There are several known factors that may impact the development of allergies, including genes, environment and lifestyle. Published in the Journal of Allergy and Clinical Immunology, the study found that a higher socioeconomic status was linked with a lower risk of asthma but a higher risk of developing hay fever. Researchers attributed this to the ‘hygiene hypothesis’, which states that growing up in a cleaner environment limits the exposure children have to microorganisms, leading to an increased risk of them being diagnosed with allergies.

Individuals with a high BMI — the measure of body fat based on height and weight — also had an increased risk of asthma, hay fever and eczema. On the other hand, those who had a higher birth weight were less likely to develop these allergies.

However, there were potential underlying factors that may have influenced the findings; for instance, mothers who had the diseases may have been recommended to breastfeed or not. Researchers were also careful to note that this was an observational study only, and therefore it was not possible to make clinical recommendations based on the results.

While the study suggested that breastfeeding might not protect babies from developing hay fever and eczema, this does not mean the researchers discourage women from breastfeeding. Breast milk contains antibodies to help babies fight off harmful bacteria and other germs, making it beneficial for their health, but Ek suggests that this research may “give a more correct picture of the health benefits of breastfeeding”.