Studies have demonstrated that the amelioration of cerebral ischemia–reperfusion injury and Parkinson’s disease, as well as age-related brain injury reduction, are closely associated with the microbiota–gut–brain axis through the reduction in oxidative stress response, inhibition of the NF-κB signaling pathway, and prevention of colonic tight junction protein degradation [52,53,54]. This evidence concerns the gene NFKB1 and age.