Holdemanella

Metal Dependencies#

Holdemanella species are obligate anaerobes with metabolic requirements typical of Firmicutes—Iron-dependent enzymes for anaerobic fermentation and Butyrate production pathways. The genus remains poorly characterized at the metallomic level, representing an important research gap given its apparent ecological importance.

Ecological Role#

A Candidate Keystone Commensal#

Holdemanella belongs to the healthy core microbiota.

In a study of inflammatory bowel disease in Western China, Holdemanella was identified alongside Christensenellaceae R-7 group and Fusicatenibacter as part of the core commensal community consistently depleted in both Crohn's disease and ulcerative colitis (,^{[1]Wang 2024 — Integrated 16S rRNA sequencing and metagenomics insights into microbial dysbiosis and distinct virulence factors in inflammatory bowel diseaseHaijing Wang, Yuanjun Wang, Libin Yang et al. · 2024Open reference 1 ↓} case-control, n=36).

This shared depletion across two distinct IBD subtypes suggests Holdemanella occupies a fundamental ecological niche rather than being condition-specific.

Omega-3 Association#

Consuming omega-3-rich fish is associated with increased Holdemanella abundance (,^{[2]Zhang 2024 — Gut Microbiota and Postpartum Depression: A Mendelian Randomization StudyJianjun Zhang, Lechuan Wei, Hongfei Tan et al. · 2024Open reference 2 ↓} computational-prediction), suggesting a dietary-microbiome-mood axis where omega-3 intake supports Holdemanella colonization, which in turn may protect against depression. This positions Holdemanella as a potential mediator of the well-documented anti-depressant effects of omega-3 fatty acids.

Restoration by Probiotics#

In a randomized controlled trial of probiotic supplementation during thyroid hormone withdrawal, Holdemanella increased in the probiotic group alongside improvements in constipation, energy levels, and intestinal barrier integrity (,^{[3]Lin 2022 — Probiotics alleviate oral-gut microbiota dysbiosis in thyroid cancer patients after thyroidectomy: RCTBaiqiang Lin, Fuya Zhao, Yang Liu et al. · 2022Open reference 3 ↓} RCT, n=39).

This suggests Holdemanella benefits from the ecological restoration provided by probiotic colonization even when not included in the probiotic formulation itself.

Conditions Associated#

Consistent Depletion Pattern#

• Inflammatory bowel disease—Depleted in both Crohn's disease and ulcerative colitis as part of the healthy core microbiota (,^{[1]Wang 2024 — Integrated 16S rRNA sequencing and metagenomics insights into microbial dysbiosis and distinct virulence factors in inflammatory bowel diseaseHaijing Wang, Yuanjun Wang, Libin Yang et al. · 2024Open reference 1 ↓} case-control). IBD causally decreases Holdemanella abundance (,^{[4]Gut Microbiota Does Not Play a Mediating Role in the Causal Association Between Inflammatory Bowel Disease and Several Its Associated Extraintestinal ManifestationsLu W, Cen J, Dai Q et al. · 2024Open reference 4 ↓} computational-prediction).
• Hashimoto's thyroiditis—Depleted in autoimmune thyroid disease (^{[5]Fang et al. 2024 — Gut Microbiota and Autoimmune Thyroid Disease: A Bidirectional Mendelian Randomization Study and Mediation AnalysisFang Y, Zhang X, Huang R et al. · 2024Open reference 5 ↓})
• Post-thyroidectomy Dysbiosis—Restored by probiotic intervention (,^{[3]Lin 2022 — Probiotics alleviate oral-gut microbiota dysbiosis in thyroid cancer patients after thyroidectomy: RCTBaiqiang Lin, Fuya Zhao, Yang Liu et al. · 2022Open reference 3 ↓} RCT)
• Post-stroke depression—Negatively correlated with HAMD depression scores

Cross-References#

• Inflammatory Bowel Disease (IBD)—Consistently depleted core commensal
• Postpartum Depression—Causal MR protective evidence
• butyrate—Primary beneficial metabolite
• Hashimoto's Thyroiditis—Depleted in autoimmune thyroid disease
• Lachnospiraceae—cobalt (Co)-depleted in IBD; fellow keystone commensal candidate
• dysbiosis—Holdemanella loss as a marker of ecological destabilization
• Gut-Brain Axis—Potential mediator of omega-3 anti-depressant effects