A recent study out of the University of Chicago and Stanford University on pairs of twins found distinct differences in the fecal microbial profiles of allergic and non-allergic individuals. In other words, what food went into the twins did not come out the same. The bacteria living in the gut changed it, and this study wanted to know more.
This is the first ever study to compare microbial metabolites in people with and without food allergies.
Fecal microbiome and metabolome differ in healthy and food-allergic twins
The study “Fecal microbiome and metabolome differ in healthy and food-allergic twins,” grew out of prior research in the Nagler laboratory at UChicago on the fecal microbiota in infants. The study included 13 twin pairs in which one twin had food allergies and the other did not. There were also an additional five pairs in which both twins had at least one food allergy.
In the study, the researchers exposed one group of mice to the feces of a healthy twin and the other group of mice to the feces of a twin allergic to cow’s milk. Later, when exposed to cow’s milk, the “healthy” mice did not react. But, the “allergic” mice experienced anaphylaxis.
The data showed key differences in the fecal microbial metabolites (the molecules the bacteria make during their life processes).
Following these results, the researchers were able to determine that there were more microbiata (communities of microorganisms that live in the gut) in the healthy twins than the allergic twins. This translates to more protection against an allergic response. The more microbiata, the less likely food allergies developed.
Researchers identified 64 distinct sets of bacterial species that set apart the healthy twin and the allergic twin groups. “The enrichment of diacylglycerol in healthy twins is of particular interest for its potential as a readily measurable fecal biomarker of health.” In other words, the creation of a certain molecule in the healthy twin is something that can easily be measured to determine if they are healthy or sick.
Furthermore, the study found that bacterial differences identified in the twins persisted throughout life, even though the adult participants lived apart from their siblings after reaching adulthood.
What’s next for food allergy studies?
“Is this a cause-and-effect relationship? We do not know. We want to understand what bacteria are associated with food allergies and what bacteria are linked with protection against food allergies,” said Stanford immunologist Kari Nadeau, MD, PhD, the study’s co-senior author.