In a world where it seems like a new food allergy is discovered every day, new research offers a glimmer of hope. A team of scientists at the University of Chicago has found a way to use a combination of a beneficial gut bacteria and a simple sugar to not only prevent but also treat food allergies in mice. Their findings challenge the traditional view that food allergies are a life-long sentence and instead suggest that they may be a curable condition rooted in an imbalance in the gut.
Food allergies are a major health concern, affecting millions of people, especially children, and can cause life-threatening reactions. The modern world is teeming with factors that can disrupt the delicate balance of our gut microbiome, from overusing antibiotics to a diet lacking fiber. This new study shifts the focus from treating the symptoms of an allergy to restoring the gut’s health, which, in turn, may help the body tolerate foods that once caused it harm.
A Powerful Combination for Gut Health
The researchers, led by Dr. Cathryn Nagler, zeroed in on a specific bacteria called Anaerostipes caccae, which is commonly found in the guts of healthy infants but is often missing in children with food allergies. This discovery led the researchers to believe that this microbe has a protective effect against allergic reactions.
They also identified a crucial substance produced by this bacteria: butyrate. Butyrate is a molecule that is a key player in maintaining a healthy gut. It helps strengthen the intestinal barrier and has strong anti-inflammatory properties.
However, the researchers quickly realized that the microbe alone wasn’t enough. It needed a food source to thrive in the gut. This is where a simple sugar called lactulose comes in. Lactulose is not digested by our bodies, so it travels to the lower gut where other bacteria ferment it. Anaerostipes caccae then feeds on the byproducts of this fermentation to produce a powerful amount of butyrate. This combination of a beneficial microbe and its food source is known as a synbiotic.
Lauren Hesser, a former Ph.D. student and lead author on the paper, said the function of the bacteria is more important than its mere presence. She explained that it was only after they added the lactulose that Anaerostipes caccae produced the desired effect.
Promising Results in Mice
To test their theory, the scientists conducted a series of experiments on mice. In one set of experiments, they transferred gut bacteria from healthy infants and infants with cow’s milk allergies into sterile mice. The mice that received the healthy gut bacteria were protected from allergic reactions, while the mice that received the allergic gut bacteria had a strong anaphylactic response when exposed to the cow’s milk allergen. When the researchers treated the allergic mice with the synbiotic, they observed a significant increase in butyrate levels and a blunting of the allergic reaction.
In another experiment, the scientists treated mice with antibiotics to disrupt their gut microbiome and then sensitized them to peanuts. The mice were then treated with either the synbiotic, the bacteria alone, or lactulose alone. The synbiotic treatment proved to be the most effective in reducing the severity of the allergic response. The findings show that while the bacteria is the main therapeutic component, the lactulose is what allows it to be effective at producing butyrate.
Beyond the physical allergic response, the synbiotic also had a positive impact on the immune system. The treatment reduced the production of inflammatory proteins and increased a type of cell that helps suppress allergic reactions. These immune system changes point to the synbiotic’s ability to fundamentally alter how the body responds to allergens.
In the end, this research suggests a powerful idea: that by restoring the balance of our gut, we may be able to help our bodies overcome food allergies.
Paper Summary
Methodology
The researchers studied the gut microbiota of healthy infants and those with cow’s milk allergies by transferring these bacterial communities into sterile mice. They then isolated a strain of the bacteria Anaerostipes caccae from a healthy infant’s feces and combined it with the prebiotic sugar lactulose to create a synbiotic. This synbiotic was administered to mice to test its ability to prevent and treat allergic responses.
Results
The synbiotic treatment increased butyrate levels in the mice’s guts and significantly reduced allergic responses to both cow’s milk and peanuts. The treatment also reduced the expression of inflammatory proteins and increased the population of immune cells that suppress allergic reactions. The research also showed that a freeze-dried version of the synbiotic was just as effective as the liquid version.
Limitations
This study was conducted on mouse models, and the results may not directly translate to humans. Additionally, the fecal microbiota from the infants with cow’s milk allergies had been stored for six years, which could have potentially altered the bacteria’s composition.
Funding and Disclosures
The research was funded by the National Institute of Allergy and Infectious Diseases and the Food Allergy Fund.
Publication Information
The paper, titled “A synbiotic of Anaerostipes caccae and lactulose prevents and treats food allergy in mice,” was published in the journal Cell Host & Microbe on July 10, 2024.