A new study published in Nature has found a direct link between a nutrient found in common breakfast foods, gut bacteria, and the immune system. The research shows that certain gut microbes can turn dietary choline into a chemical messenger that strengthens the body’s first line of defense in the intestines.
The study, conducted by researchers using a specialized screening tool, tested 100 different strains of gut bacteria. They compared how the bacteria behaved in a lab dish versus inside a living mouse. The key difference was that inside the body, the bacteria had access to dietary nutrients like choline, which are not present in standard lab conditions.
The researchers focused on two bacterial strains: Bifidobacterium breve, which is common in the guts of infants, and Pediococcus pentosaceus, a probiotic strain found in fermented foods. They found that these bacteria could convert choline into acetylcholine, a chemical messenger that the body uses for nerve signaling and muscle movement. The conversion only happened when choline was available. The team also identified the specific bacterial enzymes responsible for this process.
To confirm the effect, the researchers created a modified version of B. breve that could not produce acetylcholine. When mice were given the normal, acetylcholine-producing bacteria, three things happened. First, levels of intestinal IgA, an antibody that coats the gut lining and acts as a barrier against pathogens, increased. Second, the overall makeup of the gut microbiome changed. Third, the mice showed greater resistance to gut infection.
The study describes this as a direct connection between diet, the microbiome, and the host. The choline a person eats feeds bacteria that then produce acetylcholine, and that chemical strengthens the gut’s immune defenses. IgA is the antibody that patrols the intestinal lining, distinguishing between harmless microbes and dangerous pathogens. When IgA levels are strong, the gut is better equipped to stop infections.
This research was conducted in mice, and more work is needed to confirm how these findings apply to humans. However, the specific mechanisms identified, including the bacterial enzymes and the outcomes related to IgA and infection resistance, make the findings meaningful. Foods rich in choline include eggs, especially the yolk, liver, legumes, and salmon. The study also suggests that eating a fiber-rich diet supports the growth of bacteria like Bifidobacterium breve. Fermented foods such as kimchi, sauerkraut, and certain dairy products contain Pediococcus strains.
