A recent study has shown that a group of bacteria commonly found in the gut may protect against food allergies. Probiotics are friendly, healthy bacteria that live in the intestines of humans and help with digestion and the immune system.
The study suggests that correct probiotic use could prevent potentially life threatening anaphylactic reactions to foods such as peanuts.
Professor Cathyrn Nagler (University of Chicago), the lead author says, “Environmental stimuli such as antibiotic overuse, high fat diets, caesarean birth, removal of common pathogens and even formula feeding have affected the microbiota with which we’ve co-evolved.”
The study took two groups of mice, those who were raised in a sterile environment and had no bacteria in their intestines and those who were on antibiotics, which reduce the probiotic activity. Both groups had a strong immunological response to peanuts and produced higher levels of antibodies against peanut allergens compared to mice with normal gut bacteria.
They then introduced two types of bacteria into the mice. Those with ‘Clostridia’ bacteria lost sensitivity to the peanuts whilst those with the other bacteria, ‘Bacteroides’, remained sensitive.
The researchers believe that Clostridia caused innate immune cells to produce high levels of a signaling molecule (IL-22) which made the intestine less permeable to substances entering the blood stream. The first step to becoming allergic to something is for it to pass into the blood and contact the immune system.
“The presence of these bacteria regulates that process,” says Nagler, but she cautions that more work needs to be done to prove the effect also happens in humans.
Potential Role for Probiotics
The study is exciting because it identifies a particular bug and the mechanism by which it may protect against food allergies. It is important to understand that this study was in mice and so it may be that there is a potential role for probiotics in the prevention of food allergies in humans; studies need to be done.
There are several factors to explore with probiotics. They are not all are the same; the word ‘Probiotics’ refers to a huge group of therapeutic bacteria that have beneficial effects in the digestive process. They are all different and have different effects on digestion and the immune system. The overall event of an allergic reaction is made up of many stages and interactions. Having the right probiotics present is only part of the picture.