Parasutterella

Parasutterella excrementihominis is a Gram-negative, obligate anaerobic bacterium within the Betaproteobacteria class that has gained attention as an emerging biomarker across metabolic, inflammatory, and endocrine conditions. Despite its relatively recent characterization, Parasutterella appears prominently in MR studies and dietary intervention trials.

Metabolic Functions

Succinate Production

  • P. excrementihominis is a succinate producer rather than a classical SCFA (butyrate/propionate) producer.
  • Succinate serves as both a metabolic intermediate and an immune signaling molecule, activating succinate receptor 1 (SUCNR1/GPR91) on dendritic cells and macrophages.
  • This positions Parasutterella as a modulator of innate immune responses through its metabolic output.

Bile Acid Metabolism

  • Implicated in bile acid transformation pathways, potentially influencing the enterohepatic circulation of bile acids.
  • Its role in bile acid metabolism connects to broader effects on cholesterol handling and lipid homeostasis.

Lipid Associations

  • MR analyses link Parasutterella to higher ApoB and LDL-cholesterol levels [1], suggesting a causal role in lipid metabolism.
  • Decreased following ketogenic diet intervention in CRC models [2], consistent with dietary fat composition influencing its abundance.

Disease Associations

Cardiovascular Disease

  • MR evidence identifies Parasutterella as protective against coronary artery disease (OR=0.936) [3].
  • This protective CVD association exists despite its positive correlation with LDL-C, suggesting complex mechanisms beyond simple lipid effects.

Endometriosis

  • Enriched in mouse models of endometriosis, identified as one of ten characteristic bacteria with high LDA scores in endometriotic mice [4].
  • Also enriched alongside Bifidobacterium in endometriosis mouse models [5].

Autoimmune Thyroiditis

  • Significantly increased after 4 weeks of gluten-free diet in autoimmune thyroiditis patients (p=0.008), alongside increases in Desulfobacterota and Proteobacteria [6].
  • Its increase on GFD connects to emerging roles in tryptophan metabolism metabolism and gut-immune interactions.

IBD

  • Altered in inflammatory bowel disease, with context-dependent changes in Crohn's disease versus ulcerative colitis.
  • Its Proteobacteria lineage places it in a phylum that is generally expanded in IBD-associated dysbiosis.

Dietary Responsiveness

Parasutterella is notably responsive to dietary interventions:

  • Decreased by lactobacillus supplementation [7].
  • Decreased by ketogenic diet [2].
  • Increased by gluten-free diet [6].

Connections

  • cardiovascular disease — MR-identified protective factor against CAD
  • endometriosis — enriched in endometriosis mouse models
  • inflammatory bowel disease — altered in IBD as a Proteobacteria member
  • — involved in bile acid transformation pathways
  • dysbiosis — responsive to dietary interventions and probiotic supplementation
  • — emerging role in tryptophan metabolism and immune modulation
  • — MR-linked to ApoB and LDL-C levels

References (7)

  1. Da Teng, Wenjuan Jia, Wenlong Wang et al. (2024). Causality of the gut microbiome and atherosclerosis-related lipids: a bidirectional Mendelian Randomization study. BMC Cardiovascular Disorders. doi:10.1186/s12872-024-03804-3
  2. Qinhan Gao, Yuwen Liu, Fayu Su et al. (2026). Ketogenic diet suppresses colorectal cancer through reshaping gut microbiota and modulating the intestinal FXR/NF-kB signaling pathway. Food Science and Human Wellness. doi:10.26599/FSHW.2025.9250565
  3. Xiao-Ce Dai, Yi Yu, Si-Yu Zhou et al. (2024). Assessment of the causal relationship between gut microbiota and cardiovascular diseases: a bidirectional Mendelian randomization analysis. BioData Mining. doi:10.1186/s13040-024-00356-2
  4. Zhexin Ni, Shuai Sun, Yanli Bi et al. (2020). Ni 2020 — Fecal Metabolomics and Gut Microbiota Correlation in Endometriosis Mice. American Journal of Reproductive Immunology. doi:10.1111/aji.13307
  5. Ming Yuan, Dong Li, Zhe Zhang et al. (2018). Yuan 2018 — Endometriosis Induces Gut Microbiota Alterations in Mice. Human Reproduction. doi:10.1093/humrep/dex372
  6. Rodziewicz A, Szewczyk A, Bryl E (2024). Rodziewicz et al. 2024 — Gluten-Free Diet Alters the Gut Microbiome in Women with Autoimmune Thyroiditis. Nutrients. doi:10.3390/nu16050685
  7. Xiaoliang Xie, Wenjing Wang, Haiming Zhang et al. (2025). Cholesterol-induced colorectal cancer progression and its mitigation through gut microbiota remodeling and simvastatin treatment. BMC Cancer. doi:10.1186/s12885-025-14379-3

Related Articles