Marker Guide

Propionate producing microbes 

What this marker measures

The collective capacity of the microbial community to produce propionate, a short-chain fatty acid (SCFA) generated through the fermentation of dietary fibre and other fermentable substrates. Propionate may help regulate intestinal inflammation by supporting regulatory T-cell activity and modulating immune responses through short-chain fatty acid receptors^1–4.

Clinical associations

Consider this marker when your patient presents with:

Immune dysregulation

Conditions where immune modulation via SCFAs may be relevant

Gut fermentation balance

Consider when propionate-producing potential is high relative to butyrate-producing potential, suggesting an imbalance between these SCFA producers

Dietary context

Low fibre intake, restricted diet, poor dietary variety

Interpreting the result

All results are compared to Microba's healthy cohort to determine whether they fall within or outside the expected range.

LOW

Propionate producing potential is lower expected

May indicate reduced microbial capacity to support SCFA-mediated immune regulation. Action: see patient management insights below.

Within Range

Propionate producing potential is within expected parameters

This suggests microbial capacity to support propionate-mediated intestinal immune regulation.

HIGH

Propionate producing potential is higher than expected

Usually not a concern in isolation but may indicate an altered SCFA profile if elevated relative to butyrate-producing potential. Interpret alongside other SCFA markers, symptoms, and diet.

Patient management insights

Increase propionate production through dietary fibre and probiotic support.

Dietary strategies

A diet rich in wholegrains may increase plasma propionate.^5,6
GRADE D

Frequent intake of oats may increase plasma propionate.⁷GRADE D

Supplementation - Prebiotic

In vitro stool fermentation studies suggest arabinoxylan may increase propionate production.
GRADE PP IV

In vitro stool fermentation studies suggest lactulose may increase propionate production.
GRADE PP IV
‍
In vitro stool fermentation studies suggest psyllium may increase propionate production.
GRADE PP IV

Lifestyle factors

Lactobacillus plantarum 299v may increase plasma propionate⁸
GRADE D

Tips for patients discussion

Your report shows lower-than-ideal gut microbial diversity. Think of your microbiome like a garden: we want many different species, not just a few dominant ones. A key way to support diversity is eating a varied, minimally processed diet with diverse plant foods and quality proteins.

The community

Proprionate is not produced by a single species, it’s a community-level function. Here are some of the most commonly-detected species, however this list is not exhaustive

Alistipes finegoldii
Alistipes obesi
Alistipes onderdonkii
Alistipes putredinis
Alistipes shahii
Alistipes_A ihumii
Bacteroides caccae
Bacteroides cellulosilyticus
Bacteroides ovatus
Bacteroides stercoris
Bacteroides thetaiotaomicron
Bacteroides uniformis
Bacteroides xylanisolvens
Bacteroides_B dorei
Bacteroides_B massiliensis
Bacteroides_B vulgatus
Barnesiella intestinihominis
Blautia_A obeum
Coprococcus_A catus
Eubacterium_E hallii
Eubacterium_E hallii_A
Odoribacter splanchnicus
Parabacteroides distasonis
Parabacteroides merdae

How results are calculated

All microbiome marker results are compared against the Microba Healthy Cohort — a purpose-built reference group of more than 450 healthy individuals, collected and analysed using the same workflow as patient samples.

Each marker is scored by comparing the patient's relative abundance against the cohort average. The distance from this average is expressed as standard deviations, and determines whether a result is classified as Low, Borderline, or High.

How the result scale works

▲ AVG (Healthy Cohort average)

The patient's relative abundance is compared to the Healthy Cohort average. A negative distance from average means the microbial group is less abundant than the Healthy Cohort. A positive distance means it is more abundant. Results falling outside the expected range are classified as borderline or high/low (borderline high/low:+/-0.68,andhigh/low:+/-1.28).

Evidence grading for patient management insights

The letter grades shown next to each patient management insight show the quality of the research behind it. Every insight provided has been through a rigorous review of the scientific literature and graded using the NHMRC Levels of Evidence, so you can see exactly how strong the evidence is before applying it in practice.

Source references for all clinical associations, interpretation definitions, and patient management insights on this card.

1. Seidel, M. et al. The effects of propionate on blood pressure and arterial function. J Hypertens 43, 1894–1898 (2025).
2. Meyer, F. et al. Propionate supplementation promotes the expansion of peripheral regulatory T-Cells in patients with end-stage renal disease. J Nephrol 33, 817–827 (2020).
3. Arpaia, N. et al. Metabolites produced by commensal bacteria promote peripheral regulatory T-cell generation. Nature 504, 451 (2013).
4. Smith, P. M. et al. The Microbial Metabolites, Short-Chain Fatty Acids, Regulate Colonic Treg Cell Homeostasis. Science 341, 569–573 (2013).
5. Sandberg, J. C., Björck, I. M. E. & Nilsson, A. C. Rye-Based Evening Meals Favorably Affected Glucose Regulation and Appetite Variables at the Following Breakfast; A Randomized Controlled Study in Healthy Subjects. PLOS ONE 11, e0151985 (2016).
6. Vetrani, C. et al. Effects of whole-grain cereal foods on plasma short chain fatty acid concentrations in individuals with the metabolic syndrome. Nutrition 32, 217–221 (2016).
7. Xu, D. et al. The Prebiotic Effects of Oats on Blood Lipids, Gut Microbiota, and Short-Chain Fatty Acids in Mildly Hypercholesterolemic Subjects Compared With Rice: A Randomized, Controlled Trial. Front. Immunol. 12, (2021).
8. Malik, M. et al. Lactobacillus plantarum 299v Supplementation Improves Vascular Endothelial Function and Reduces Inflammatory Biomarkers in Men With Stable Coronary Artery Disease. Circ Res 123, 1091–1102 (2018).