Children who acquire four kinds of gut bacteria in the first three months of their lives can be protected from developing asthma, according to new research.

The four bacteria, called FLVR (Faecalibacterium, Lachnospira, Veillonella, and Rothia), are naturally acquired by most babies through exposure in their home surroundings. However, some infants miss out, and it's those children who are at most risk of developing asthma, according to researchers from the University of British Columbia in Canada.

"This research supports the hygiene hypothesis that we're making our environment too clean," said B. Brett Finlay, the study's co-lead researcher, in a press release. "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."

The researchers looked at faecal samples from 319 children who took part in the Canadian Healthy Infant Longitudinal Development Study. The samples revealed that the three-month-old infants at high risk of developing asthma – determined by allergy tests to see if the children demonstrated wheezing – had lower amounts of FLVR bacteria than the kids who didn't show such signs of developing the disease.

The researchers also found that by one year of age, the differences in gut bacteria between the high-risk and low-risk children had significantly lessened, suggesting that early exposure to FLVR bacteria in those first three months of life could be crucial in warding off asthma later on.

"What I think is important and not so surprising to paediatricians was how important the very early life is," Stuart Turvey, co-author of the research, told Arielle Duhaime-Ross at The Verge. "And our study emphasises that in that first 100 days the structure of the gut microbiome seems to be very important in influencing the immune responses that cause or protect us from asthma."

The researchers confirmed their findings in mice, and found that adding the bacteria to germ-free mice decreased airway inflammation in the animals, suggesting a similar treatment for humans may also be possible.

More work is needed to be done, however. First, the researchers want to conduct a larger study with a greater number of infants to examine further how FLVR bacteria impact the development of asthma in children.

But the implications of the research, published in Science Translational Medicine, are already promising, suggesting avenues that could ultimately lead to stamping out the deadly disease. Twenty percent of children in western countries are affected by asthma and the condition kills hundreds of thousands of people every year, but the researchers say a probiotic treatment that could effectively inoculate infants may now be on the horizon.

"This discovery gives us new potential ways to prevent this disease that is life-threatening for many children," said co-lead researcher Stuart Turvey. "It shows there's a short, maybe 100-day window for giving babies therapeutic interventions to protect against asthma.*"