The Role of Gut Bacteria in Food Allergies
New research out of the Boston Children’s Hospital has demonstrated an important role of gut bacteria in food allergies. The scientists transplanted fecal material from human babies with and without food allergies into mice that had been engineered to have severe egg allergies. When mice received fecal matter from babies with food allergies, their egg allergies persisted. However, when they received fecal matter from healthy babies, they were protected from anaphylaxis - a potentially fatal allergic reaction.
Back in the 80s and 90s, researchers began observing that gut bacteria in animals appeared to play a role in preventing food allergies. Specifically, something about gut bacteria was ensuring that the immune system recognized foods as harmless, even though they were foreign. Normally, the immune system attacks foreign entities it deems harmless as a way to ensure health and safety.
In 2000, a new study was published showing that mice with a specific genetic mutation disrupted communication between gut bacteria and the immune system. What was fascinating, though, was that mice with this mutation also experienced anaphylaxis when they were exposed to peanuts.
Since this key combination of observations linking gut bacteria to food allergies, it has been shown that a causal relationship exists between the microbiome and food allergies. One specific species of bacteria, known as Anarostipes caccae, is important for preventing allergies to cow’s milk. This role of Anarostipes caccae was discovered when it was observed that mice with lower levels of this bacteria were more likely to have allergic reactions to cow’s milk and that transferring this bacteria to mice could protect against such allergic reactions.
How can this information on the connection between gut bacteria and food allergies be put to use?
Researchers have established ways to use differences in the microbiome to predict which children will outgrow their food allergies. Ongoing research into the mechanisms underlying this connection will hopefully lead to the development of strategies to prevent or treat food allergies. Clinical trials are currently underway to determine if probiotic supplements may provide an opportunity to combat food allergies.