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 3 pathways that produce a bidirectional flow of information (Li et al 2018):
- The immunoregulatory pathway, in which the microbiota interact with immune cells in such a way as to affect the levels of cytokines, cytokinetic reaction factor, and prostaglandin E2. As a result, brain function is affected.
- The neuroendocrine pathway. The gut microbiome may affect the hypothalamic-pituitary-adrenal (HPA) axis and the central nervous system (CNS) by regulating the secretion of neurotransmitters such as cortisol, tryptophan, and serotonin (5-HT).
- The third is the vagus nerve pathway with intestine sensory neurons forming synaptic contacts with intestine motor neurons for regulation of intestinal motility and gut hormone secretion. The intestinal nervous system also forms synaptic connections with the vagus nerve, which connects the intestine to the brain
Toribio-Mateas 2018 discussed in his paper that stress responses, driven by the activation of the sympathetic nervous system, play an important role in the dysregulation of the intestinal ecosystem. Peirce et al 2019 also investigated the bidirectional communication between the gut microbiome and the central nervous system, showing it is affected by stress. Mehrian-Shai et al., 2019 argued that microbiome dysbiosis can pave the way to brain cancer. 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. Alam et al., 2017 discussed the link between microbiome, inflammation, epigenetic alterations, and mental diseases. Romano et al 2017 researched choline-consuming gut bacteria and showed that they cause alterations to host epigenetic programming which increase anxious behaviors. Lynch 2016, Gao et al., 2017, and Beam Dowd and Renson 2018 researched how the environment, such as exposure to toxins or indoor rooms or pets, alters the microbiome. In recent studies, Miro-Blanch et al., 2019 , Beam Dowd and Renson 2018, and Toribio Mateas 2018 show that diet is a strong determinant of gut microbiome composition and diversity, and it is known that healthy people have very diverse microbiomes. 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 help you navigate the omics-gut-brain axis, and through knowledge, help yourself and others stay healthy, feel and perform at your best.