The Gut-Brain-Axis is a two-way street, with a different round trip experience in health than in disease. It is also closely linked to the immune system with bacteria causing inflammation in the body during disease states, and good, commensal bacteria strengthening the immune system through healthy habits. In recent years, omics research has revealed the gut-brain axis, which links gut bacteria to brain functioning, including moods and other mental states, as a critical factor in human health and disease. Studying the gut-brain axis involves metagenomics and metabolomics, and for more comprehensive research, it involves transcriptomics, proteomics, epigenomics and genomics. Omics research has revealed bidirectional communication pathways between the gut microbiota and the brain. The microbiota in the gut affects brain function through three primary bidirectional pathways (Agirman and Hsiao, 2021):
- The immune pathway, where microbial-derived metabolites like short-chain fatty acids (SCFAs) modulate local and systemic immunity to reach the CNS.
- The endocrine pathway, involving the hypothalamic-pituitary-adrenal (HPA) axis and the regulation of neurotransmitters such as cortisol, tryptophan, and serotonin (5-HT).
- The neuronal pathway, primarily via the vagus nerve which provides a direct physical link between the gut’s sensory neurons and the brain.
Recent research confirms that psychological and physiological stress responses modulate gastrointestinal activity, which in turn regulates the central nervous system via immune and vagal signaling (Ravenda et al, 2025). The Gut-Brain-Axis may affect behavior through modulating neurotransmission, and be involved in the pathogenesis and/or progression of different neuropsychiatric disorders such as depression (Matin and Dadkhah, 2024). Recent evidence increasingly supports a role for gut microbiome dysbiosis in shaping the risk, progression, and treatment response of brain tumors (Leigh et al 2025). It is known that during gut microbiome dysbiosis, gut bacteria and toxins can leak into the bloodstream, causing inflammation in the body. In a Nature paper by Poore at el. 2020, it was shown that studying the microbiome of blood and tissue can discriminate among samples from healthy, cancer-free individuals and those from patients with multiple types of cancer. Recent experimental studies demonstrate that gut microbiome dysbiosis can drive systemic inflammation and induce epigenetic remodeling in the brain, directly influencing neural function and behavior. In parallel, newer work shows that choline‑metabolizing gut bacteria alter host DNA and histone modification patterns through microbial metabolites, leading to measurable increases in anxiety‑related behaviors (Abdolmaleky et al. 2025). Diet is a major determinant of gut microbiome composition and diversity, and healthy individuals consistently show higher microbial diversity (Ross et al 2024). Many more studies show a link between nutrition, eating habits, fitness, sleep, social interactions, social behaviors and the microbiome.
At Lifetime Omics, we know that health is dependent on an interplay of multiple factors along the gut-brain axis and that this interplay and the directionality of interactions can be measured with omics technologies. We are here to develop AI agents that help navigate the omics-gut-brain axis and help people stay healthy, feel and perform at their best.