The human gastrointestinal (GI) tract contains a diverse mixture of commensal and pathogenic microbes, forming the gut microbiome. These gut microbes and their potential to improve human health are a topic of great interest to the scientific community. Many intestinal and age-related complications are linked to dysbiosis of the gut microbiome, often associated with a weakened immune system. A decrease in beneficial microbes, generally, along with decreased microbial diversity in the gut, can, in many cases, result in disease, particularly in older individuals. Probiotics, which are ingestible beneficial microorganisms, have the potential to positively modulate the indigenous gut microbiota. There are two predominant and conventional classes of lactic acid bacterial probiotics, lactobacilli and bifidobacteria, which have been confirmed for their health benefits and role in preventing certain gut-related disorders. The proper use of probiotics and/or supplements, along with a consistently healthy lifestyle, is a promising holistic approach to maintaining or improving gut health and minimizing other age-linked disorders. There are many properties that bacterial probiotics possess, which may allow for these beneficial effects in the gut. For instance, probiotics have adhesion capacities (capability to stay in GI tract) that are effective in excluding pathogens, while other probiotics have the potential to stimulate or modulate the intestinal immune system by regulating genes that reside within and outside of the gut environment. This review discussed the possible underlying mechanics of probiotics, evidence of probiotic-based mitigation of age-related disease, and the role of probiotics in modulating gut health and, in turn, maintaining brain health.