Megamonas

SCFA Production Profile#

Unlike the dominant Butyrate producers (Faecalibacterium prausnitzii, Roseburia), Megamonas primarily produces propionate and valerate.

Enrichment in constipated ASD children was associated with elevated propionate levels.^{[1]He 2023 — Altered Gut Microbiota and Short-Chain Fatty Acids in Chinese Children with Constipated Autism Spectrum DisorderJianquan He, Xiuhua Gong, Bing Hu et al. · 2023Open reference 1 ↓} Enrichment in ASD more broadly was associated with elevated valeric acid.^{[2]Liu 2019 — Altered Gut Microbiota and Short Chain Fatty Acids in Chinese Children with Autism Spectrum DisorderSimeng Liu, Enyao Li, Zhenyu Sun et al. · 2019Open reference 2 ↓}

M. funiformis emerged as an indicator of healthier dietary patterns in ASD children, suggesting its metabolic role may be diet-dependent.^{[3]Wu 2025 — Distinct Diet-Microbiome Associations in Autism Spectrum DisorderYuqi Wu, Oscar Wong, Sizhe Chen et al. · 2025Open reference 3 ↓}

The propionate connection is significant—Propionic Acid at elevated concentrations has been linked to ASD-like behavioral changes in animal models, while at normal concentrations it supports colonocyte health and immune regulation. The dose-response and context may determine whether Megamonas enrichment is beneficial or pathological.

Enriched#

Autism spectrum disorder (4 independent studies): Consistently overrepresented in ASD children across Chinese cohorts. Associated with elevated valeric acid^{[2]Liu 2019 — Altered Gut Microbiota and Short Chain Fatty Acids in Chinese Children with Autism Spectrum DisorderSimeng Liu, Enyao Li, Zhenyu Sun et al. · 2019Open reference 2 ↓} and elevated propionate in constipated ASD.^{[1]He 2023 — Altered Gut Microbiota and Short-Chain Fatty Acids in Chinese Children with Constipated Autism Spectrum DisorderJianquan He, Xiuhua Gong, Bing Hu et al. · 2023Open reference 1 ↓}

Functional profiling associates with SCFA production and metabolic alterations.^{[4]Deng 2022 — Gastrointestinal Symptoms Have a Minor Impact on Autism Spectrum Disorder and Associations with Gut Microbiota and Short-Chain Fatty AcidsWenlin Deng, Siqi Wang, Fang Li et al. · 2022Open reference 4 ↓} However, M. funiformis was also an indicator of healthier diet patterns in ASD, complicating the pathological narrative.^{[3]Wu 2025 — Distinct Diet-Microbiome Associations in Autism Spectrum DisorderYuqi Wu, Oscar Wong, Sizhe Chen et al. · 2025Open reference 3 ↓}

Hashimoto's thyroiditis: Increased alongside decreased Bifidobacterium and Klebsiella, part of a consistent HT dysbiosis pattern.^{[5]Mendoza-Leon et al. 2023 — Gut Microbiota Short-Chain Fatty Acids and Their Impact on the Host Thyroid Function and DiseasesMendoza-Leon MJ, Mangalam AK, Regaldiz A et al. · 2023Open reference 5 ↓} Significant genus-level differences with gender-specific and hormone-regulated patterns.^{[6]Analysis of gut microbiota diversity in Hashimoto's thyroiditis patientsLiu J, Qin X, Lin B et al. · 2022Open reference 6 ↓}

Prostate cancer: Men with high serum testosterone (>455 ng/dL) showed increased Megamonas (r=0.46, p=0.009), suggesting a testosterone-microbiome axis.^{[7]Trecarten 2025 — Obesity, Dietary Interventions and Microbiome Alterations in Prostate CancerShaun Trecarten, Michael A. Liss, Jill Hamilton-Reeves et al. · 2025Open reference 7 ↓}

Depleted#

Graves' disease: Both GD and HT groups had lower Megamonas vs. healthy controls (Kruskal-Wallis significant).^{[8]Alterations and Mechanism of Gut Microbiota in Graves' Disease and Hashimoto's ThyroiditisZhao H, Yuan L, Zhu D et al. · 2022Open reference 8 ↓} Consistent reduction across thyroid diseases.^{[9]Fang & Ning 2024 — Recent Advances in Gut Microbiota and Thyroid Disease: Pathogenesis and TherapeuticsFang L, Ning J · 2024Open reference 9 ↓}

Thyroid cancer: Decreased alongside Roseburia and Bacteroides.^{[10]Wang & Zhu 2025 — Gut Microbiome Versus Thyroid Cancer: Association and Clinical Implications (Review)Wang M, Zhu Y · 2025Open reference 10 ↓[9]Fang & Ning 2024 — Recent Advances in Gut Microbiota and Thyroid Disease: Pathogenesis and TherapeuticsFang L, Ning J · 2024Open reference 9 ↓} Heart failure: Depleted in both decompensated and compensated HF vs. controls (P<0.001).^{[11]Gut Microbiome and Plasma Microbiome-Related Metabolites in Patients With Decompensated and Compensated Heart FailureTomohiro Hayashi, Tomoya Yamashita, Hikaru Watanabe et al. · 2019Open reference 11 ↓}

Colorectal adenoma/cancer: Healthy microbiome characterized by preponderance of Megamonas and Sphingobium; depleted in adenoma and CRC progression.^{[12]Metagenomic Analyses of the Gut Microbiota Associated with Colorectal AdenomaSaito K, Koido S, Odamaki T et al. · 2019Open reference 12 ↓}

Other Associations#

Schizophrenia: Listed as a dominant genus in schizophrenia patients alongside Faecalibacterium, Ruminococcus, and Akkermansia.^{[13]The Gut Microbiome is Associated with Brain Structure and Function in SchizophreniaLi S, Song J, Ke P et al. · 2021Open reference 13 ↓} Chronic kidney disease: Abundance positively correlated with cognitive performance (attention, executive function) in hemodialysis patients.^{[14]Gao et al. 2024 — Intestinal Flora and Cognitive Function in Maintenance Hemodialysis PatientsQiuyi Gao, Dianshi Li, Yue Wang et al. · 2024Open reference 14 ↓}

Male reproductive function: Implicated in reproductive dysfunction signatures.^{[15]Lv 2024 — Gut Microbiota Is Involved in Male Reproductive Function: A ReviewShuya Lv, Jingrong Huang, Yadan Luo et al. · 2024Open reference 15 ↓}