In a previous study we demonstrated that Lactobacillus brevis KB290, which was originally isolated from Suguki, a traditional Japanese pickle, inhibits intestinal inflammation in a murine colitis model. These inhibition effects are associated with the increases in the colonic CD11c⁺ macrophages /CD103⁻ DCL dendritic cell ratio in the presence of a vitamin A (VA). We investigated the effect of KB290 and β-carotene on Japanese volunteers with non-pathological diarrhea-predominant irritable bowel syndrome (IBS-D)-like symptoms. The group treated with KB290 + β-carotene showed significant improvements in stool frequency and work productivity compared with the placebo group as well as increases in genus Bifidobacterium and decreases in genus Clostridium in stool samples.

Exercise has been found to change the composition of the gut microbiome, transforming it one that is beneficial to the metabolic system. In other words, athletes involved in rigorous activities causing damage to the body, repair the damage by proper exercise and nutrition, which in turn changes their gut microbiome into a high energy acquisition system. The gut microbiome of individuals is highly diversified, as can be seen when comparing the gut microbiome of obese and healthy individuals. It is conjectured that the gut microbiota of athletes cannot be defined by a single type of bacterial strain, and instead should be described as the “athlete type” gut microbiome.