Babies can be protected from getting asthma if they acquire four types of gut bacteria by the age of three months. Scientists say with asthma rates increasing dramatically since the 1950s, their findings support the idea that we are "making our environment too clean".
The researchers, from the University of British Columbia, analysed faecal samples from 319 children involved in the Canadian Healthy Infant Longitudinal Development Study. Findings showed lower levels of four specific types of gut bacteria in the infants led to an increased risk of asthma. They also confirmed the findings by showing mice inoculated with the bacteria at birth developed less severe asthma.
Most babies will acquire the bacteria (Faecalibacterium, Lachnospira, Veillonella, Rothia) from their environments naturally. However, some do not do so for a number of reasons. Dr B. Brett Finlay, co-lead research on the study, said: "The bacteria and other microorganisms that inhabit ... us as part of our normal lives may actually play a role in this.
"Things such as a Caesarean section versus a vaginal section increases your risk of asthma, breastfeeding decreases in compared to bottle-feeding, antibiotics in the first year of life significantly increasing incidents having a pet or living on a farm decrease it. So there's all these sort of smoking guns to indicate that the microbiota may be involved in this, but there were no experiments to prove it."
The study, published in the journal Science Translational Medicine, provides a new avenue for developing probiotic treatments in order to prevent asthma, as well as predicting children at risk of developing the respiratory condition.
Stuart Turvey, co-lead researcher, added: "This discovery gives us new potential ways to prevent this disease that is life-threatening for many children. It shows there's a short, maybe 100-day window for giving babies therapeutic interventions to protect against asthma."
Finlay said: "This research supports the hygiene hypothesis that we're making our environment too clean. It shows that gut bacteria play a role in asthma, but it is early in life when the baby's immune system is being established."