Bacteria in the gut may prevent allergies Mayte Torres/Getty

A species of gut bacteria may be responsible for preventing allergies in children.

Allergies have become much more common in industrialised countries since the mid-20th century, but it’s still not clear why.

Some evidence points to the microbiome – the community of bacteria that live inside our bodies – as a possible factor. Children whose mothers take probiotic supplements seem to have a lower risk of allergies, while those born by caesarean section, which affects the acquisition of bacteria in the gut, may have a higher risk.

Cathryn Nagler at the University …