Recent advances in microbiology have led to the recognition of the gut microbiota as an essential component contributing to the aging process. The gut microbiota is a diverse ecosystem of microorganisms residing in the gastrointestinal tract that profoundly influences host health. This journal entry aims to explore the mechanisms by which the gut microbiota influences aging and potential interventions for healthier aging, drawing on relevant scientific literature.
Gut Microbiota Composition and Aging: As individuals age, there are notable changes in the gut microbiota composition, termed "gut dysbiosis," with a decrease in beneficial bacteria and an increase in pathogenic species. Numerous factors contribute to age-related gut dysbiosis, including alterations in dietary patterns, reduced physical activity, and medications. A longitudinal study by demonstrated that the gut microbiota of centenarians differs significantly from younger individuals, emphasizing the role of the gut microbiota in the aging process.1 This study was followed up by another cross sectional investigation published in 2023 in Nature that found that ‘highlight a youth-related aging pattern of the gut microbiome for long-lived individuals’. 2
Influence of Gut Microbiota on Inflammation and Immune Function: Chronic low-grade inflammation, known as "inflammaging," is a hallmark of aging and is associated with several age-related diseases. The gut microbiota plays a crucial role in regulating inflammation through interactions with the gut lining and the immune system. Certain gut microbes, such as Faecalibacterium prausnitzii, produce anti-inflammatory metabolites like butyrate, which attenuates pro-inflammatory cytokine production.3. Butyrate, a short-chain fatty acid, has emerged as a key player in the gut microbiota's influence on aging.
Butyrate and Aging: Mechanisms of Action
Anti-Inflammatory Effects: Butyrate has potent anti-inflammatory properties. It functions as a histone deacetylase (HDAC) inhibitor, promoting the acetylation of histones in the nucleus of cells. This epigenetic modification results in the upregulation of anti-inflammatory genes and downregulation of pro-inflammatory genes, leading to reduced systemic inflammation associated with aging.4.
Maintenance of Gut Barrier Integrity: Butyrate plays a pivotal role in maintaining the integrity of the intestinal barrier. It enhances the production of tight junction proteins, such as occludin and claudin-1, which help seal the gaps between intestinal epithelial cells, preventing the leakage of harmful microbial products into the bloodstream.5 This function is crucial in preventing age-related intestinal permeability.
Energy Metabolism and Mitochondrial Function: Aging is often accompanied by a decline in mitochondrial function. Butyrate serves as an energy source for colonocytes and can improve mitochondrial function in these cells.6 This may have implications for maintaining overall energy metabolism and reducing age-related fatigue.
Regulation of Immune Responses: Butyrate can modulate immune responses in the gut. It promotes the development of regulatory T cells (Tregs), which help maintain immune tolerance and prevent excessive immune activation.7 Dysregulation of immune responses is a hallmark of aging, and butyrate's role in immune homeostasis is of significant interest.
Butyrate also plays a role in key hallmarks of aging.
While aging is a complex process influenced by a multitude of cellular mechanisms, there are areas that are well established as being critical in the field of longevity science and it so happens that butyrate is a driver for optimization in those areas.
Firstly, butyrate is closely intertwined with mitochondrial function, the cellular powerhouses responsible for generating adenosine triphosphate (ATP). Aging often brings about mitochondrial dysfunction, contributing to the overall cellular and tissue decline. Butyrate enhances mitochondrial activity through various means, serving as an additional energy source for colonocytes and supporting the tricarboxylic acid (TCA) cycle, essential for ATP production in mitochondria.6 Additionally, butyrate's anti-inflammatory properties may reduce systemic inflammation, potentially mitigating the generation of reactive oxygen species (ROS) within mitochondria, which can damage mitochondrial DNA and proteins.4
Moreover, butyrate's influence also extends to telomere shortening, a hallmark of cellular aging. While direct effects on telomere length remain less explored, butyrate's impact on inflammation and reduction of oxidative stress may indirectly influence telomere maintenance. Chronic inflammation and oxidative stress often accelerate telomere shortening, but by reducing these factors, butyrate may help slow down the rate of telomere erosion.8
Further, butyrate has intriguing interactions with senescent cells, which are associated with inflammaging, the age-related chronic inflammation. Butyrate might facilitate senescence reversal, potentially reactivating silenced genes in senescent cells through epigenetic modifications, promoting a more youthful cellular phenotype. Additionally, butyrate's anti-inflammatory properties can help alleviate the pro-inflammatory secretions of senescent cells, reducing the harmful effects associated with cellular senescence.9
Finally, butyrate has implications for autophagy, a critical cellular process that recycles damaged cellular components and maintains homeostasis. While its role in autophagy is not yet fully elucidated, some research suggests that butyrate can induce autophagy by regulating various autophagic genes and pathways, including activation of AMPK, inhibition of mTOR, enhance Beclin-1 and promote the conversion of LC3-I to its lipidated form, LC3-II, which is associated with the autophagosomal membrane and is a marker of autophagy activation.10
The gut microbiota's impact on the aging process is a rapidly advancing field with profound implications for promoting healthy aging. Scientific evidence demonstrates that the gut microbiota influences aging through mechanisms involving inflammation, immune function, nutrient absorption, and the gut-brain axis. Butyrate emerges as a key mediator in these processes, with its anti-inflammatory effects, role in maintaining gut barrier integrity, impact on energy metabolism, and regulation of immune responses. Therapeutic strategies targeting butyrate-producing gut microbes or supplementing with butyrate itself or a butyrate generator, such as Butyragen, hold promise for promoting healthy aging and mitigating age-related disorders. As the aging population continues to expand, further research into the gut microbiota's role in aging will pave the way for innovative and personalized interventions to enhance healthy aging and overall well-being.
- Biagi E, Franceschi C, Rampelli S, Severgnini M, Ostan R, Turroni S, Consolandi C, Quercia S, Scurti M, Monti D, Capri M, Brigidi P, Candela M. Gut Microbiota and Extreme Longevity. Curr Biol. 2016 Jun 6;26(11):1480-5. doi: 10.1016/j.cub.2016.04.016.
- Pang, S., Chen, X., Lu, Z. et al. Longevity of centenarians is reflected by the gut microbiome with youth-associated signatures. Nat Aging 3, 436–449 (2023). https://doi.org/10.1038/s43587-023-00389-y
- Rivière A, Selak M, Lantin D, Leroy F, De Vuyst L. Bifidobacteria and Butyrate-Producing Colon Bacteria: Importance and Strategies for Their Stimulation in the Human Gut. Front Microbiol. 2016 Jun 28;7:979. doi: 10.3389/fmicb.2016.00979.
- Ríos-Covián D, Ruas-Madiedo P, Margolles A, Gueimonde M, de Los Reyes-Gavilán CG, Salazar N. Intestinal Short Chain Fatty Acids and their Link with Diet and Human Health. Front Microbiol. 2016 Feb 17;7:185. doi: 10.3389/fmicb.2016.00185.
- Canani RB, Costanzo MD, Leone L, Pedata M, Meli R, Calignano A. Potential beneficial effects of butyrate in intestinal and extraintestinal diseases. World J Gastroenterol. 2011 Mar 28;17(12):1519-28. doi: 10.3748/wjg.v17.i12.1519
- Donohoe DR, Collins LB, Wali A, Bigler R, Sun W, Bultman SJ. The Warburg effect dictates the mechanism of butyrate-mediated histone acetylation and cell proliferation. Mol Cell. 2012 Nov 30;48(4):612-26. doi: 10.1016/j.molcel.2012.08.033.
- Arpaia N, Campbell C, Fan X, Dikiy S, van der Veeken J, deRoos P, Liu H, Cross JR, Pfeffer K, Coffer PJ, Rudensky AY. Metabolites produced by commensal bacteria promote peripheral regulatory T-cell generation. Nature. 2013 Dec 19;504(7480):451-5. doi: 10.1038/nature12726.
- Rossiello F, Jurk D, Passos JF, d'Adda di Fagagna F. Telomere dysfunction in ageing and age-related diseases. Nat Cell Biol. 2022 Feb;24(2):135-147. doi: 10.1038/s41556-022-00842-x.
- Yosef R, Pilpel N, Tokarsky-Amiel R, Biran A, Ovadya Y, Cohen S, Vadai E, Dassa L, Shahar E, Condiotti R, Ben-Porath I, Krizhanovsky V. Directed elimination of senescent cells by inhibition of BCL-W and BCL-XL. Nat Commun. 2016 Apr 6;7:11190. doi: 10.1038/ncomms11190.
- Chen, L., et al. (2018). Autophagy Inhibition Contributes to ROS-Producing NLRP3-Dependent Inflammasome Activation and Cytokine Secretion in High Glucose-Induced Macrophages. Cellular Physiology and Biochemistry, 43(1), 247-256.