Asthma affects hundreds of millions of people across the world. New research links the gut's microbes with the risk of developing asthma, and identifies a specific fungus in babies that might increase the risk of childhood asthma.
Historically, it was believed that asthma is a disease of high-income countries, but this theory is no longer valid as most people living with asthma are from low- and middle-income countries.
Across the world, asthma prevalence is distributed unevenly. The highest prevalence worldwide occurs in Latin America and in English-speaking countries (where over 20 percent of the population live with asthma), whereas the lowest prevalence (at less than 5 percent) was noted in India, Asia-Pacific, and the Eastern part of the Mediterranean, as well as Northern and Eastern Europe.
Countries such as Canada and Ecuador both have a significant incidence of the disease, with approximately 10 percent of the population living with asthma.
New research suggests that a yeast in the gut of Ecuador-born babies may be a strong predictor for childhood asthma. The study was carried out by a team of researchers from the University of British Columbia in Canada and was led by microbiologist Brett Finlay.
The findings were presented at the annual meeting for Association for the Advancement of Science in Boston, MA.
Pichia fungus increases risk of asthma
In the past, Finlay and his colleagues examined the gut microbiota of Canadian children and its connections to asthma. They found four gut bacteria that appeared to prevent the onset of asthma if they were present in the infants' guts within the first 3 months of life.
Now, in this follow-up study, Finlay and team replicated the experiment in an Ecuadorian village, in an attempt to investigate whether the beneficial role of the gut's microbiome is universal.
Using stool samples and health information from more than 100 children, scientists found that the gut's bacteria do play a key role in preventing asthma. However, among the early-life microbes, a yeast known as Pichia seems to increase the risk of asthma if present in the babies' early days of life.
The research further emphasizes the key role of the gut's microbiota in maintaining the body's general health and protecting against serious illness.
Bacteria living in our gut have been shown to strengthen the body's immune system, acting as a barrier against new, harmful microorganisms. The gut's microbiome - which contains more than 1,000 forms of known bacteria - also aids digestion and produces some important vitamins.
The study, led by Finlay, also looked at the cleanliness of the Ecuadorian water and environment and found some surprising conclusions.
"Those that had access to good, clean water had much higher asthma rates and we think it is because they were deprived of the beneficial microbes. That was a surprise because we tend to think that clean is good but we realize that we actually need some dirt in the world to help protect you."
To the authors' knowledge, this study is the first of its kind. "This is the first time anyone has shown any kind of association between yeast and asthma," Finlay notes.
Next, the researchers plan to re-examine the Canadian samples from their previous study and look for the recently discovered fungus in the babies' guts.