Infants may be protected from getting asthma if they acquire four specific types of gut bacteria by an early age, according to new research from the University of British Columbia.
According to the study, published Wednesday in the journal Science Translational Medicine, children who acquire the four bacteria by the time they are three months old may be protected from the disease.
"This research supports the hygiene hypothesis that we're making our environment too clean," one of the study's co-lead authors B. Brett Finlay said in a statement. "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."
For the study, the researchers examined fecal samples from 319 children. An analysis of the samples found that three-month-old infants who were at a risk for asthma had lower levels of the four bacteria.
The bacteria, which the researchers nicknamed "FLVR" (which stands for the names of the bacteria Faecalibacterium, Lachnospira, Veillonella, Rothia), are usually acquired by infants from their natural environment.
However, some infants do not acquire them due to a number of factors. For example, babies born via C-section are exposed to fewer bacteria at birth. As well, other studies have shown that babies who were treated with antibiotics before they turned one were more likely to be diagnosed with asthma.
The study also found fewer differences in the levels of FLVR among one-year-old children, which suggests that the first three months of life are a critical time period for the developing immune system.
The researchers confirmed their findings in mice, and also found that mice that were inoculated with the bacteria developed less severe forms of asthma.
Dr. Stuart Turvey, a pediatric immunologist and co-author of the study, said the research may one day lead to a way of preventing the disease.
"The importance of this study was that we were able to identify four specific bacterial genre that seem to be related to the risk of asthma," he told CTV News.
"That's important because that sets the scene for the next steps, when we think about using these bacteria as a way to prevent asthma in the future."
Asthma specialist Dr. Mark Greenwald, who is not one of the authors of the study, agrees that there does appear to be a critical developmental window of three months. After three months, the bacteria found in the gut are about the same as what you would find in an adult, he said.
"Maybe one of the messages is we're using too much antibiotics, too frequently," he told CTV News. "We're learning that the window of opportunity is literally within the first month to three months of life. Beyond that we've probably already missed the boat."
Turvey said that the study's findings may shift our societal views of bacteria.
"Often we see bacteria as something to be scared of, something to be killed with antibiotics. But really, we've evolved as humans with bacteria and they're actually really important for our health," he said.
"A simple message for families is not to be scared of letting your children play outside, engage with pets and other animals, and live a healthy active life. Don't protect them too much."
He stressed that his team is not suggesting that parents start giving their children these bacteria, noting that researchers have more work to do, including conducting studies involving a larger number of children.
With files from CTV News' Medical Correspondent Avis Favaro and Producer Elizabeth St. Philip
