Marker Guide

BCAAs producing microbes

What this marker measures

The collective capacity of the microbial community to produce branched-chain amino acids (BCAAs). Although BCAAs are essential amino acids obtained from the diet, the gut microbiome may also contribute to the body’s circulating BCAA pool. Higher BCAA-producing potential may contribute to elevated circulating BCAAs in some individuals¹. Elevated circulating BCAAs may be associated with systemic inflammation, unfavourable lipid profiles and insulin resistance.^1–4

Clinical associations

Consider this marker when your patient presents with:

Systemic inflammation and metabolic risk

Chronic low-grade systemic inflammation of unclear origin, particularly when accompanied by insulin resistance, impaired glucose regulation, or dyslipidaemia.

High levels of plasma BCAAs may be associated with systemic inflammation in women.

Interpreting the result

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

LOW

BCAA-producing potential is lower than expected

Microbial BCAA production is unlikely to be contributing to elevated circulating BCAAs.Interpret alongside diet, metabolic status, and clinical presentation.

Within Range

BCAA-producing potential is within expected parameters

This result does not suggest excess microbial contribution to circulating BCAAs.

HIGH

BCAA-producing potential is higher than expected

May contribute to elevated circulating BCAAs in some individuals, which may be associated with systemic inflammation, as well as insulin resistance and dyslipidaemia.Action: see Patient management insights guidance below.

Patient management insights

Reduce excess microbial BCAA production and support metabolic health.

Dietary strategies

High-fibre vegan diet may reduce BCAA levels in blood^5,6 C

Rye consumption may reduce fasting plasma BCAA levels in those with metabolic syndrome or elevated cholesterol^7,8C

Choosing fish in place of meat may reduce serum BCAAs in overweight individuals^9,10D

A Mediterranean diet may reduce plasma BCAA levels^11,12D

Exercise strategies

Exercise may support insulin sensitivity by promoting enhanced BCAA breakdown.^{13, 14, 15, 16}GRADED

Tips for patients discussion

Your report shows an elevated capacity for gut microbes to produce branched-chain amino acids (BCAAs). While these are essential, higher circulating levels have been linked to insulin resistance, inflammation and metabolic risk in some people. Regular exercise and a shift towards fibre-rich plant foods, fish or plant-based proteins, and Mediterranean-style eating help support healthier BCAA metabolism

The community

BCAAs are not produced by a single species, it's a community-level function. Below are some of the most common, though this list is not exhaustive.

Agathobacter faecis
Alistipes obesi
Alistipes onderdonkii
Alistipes shahii
Bacteroides caccae
Bacteroides ovatus
Bacteroides thetaiotaomicron
Bacteroides uniformis
Bacteroides_B dorei
Bacteroides_B vulgatus
Barnesiella intestinihominis
Blautia_A sp900066165 sp900066165
CAG-41 sp900066215
CAG-56 sp900066615
Fusicatenibacter saccharivorans
GCA-900066135 MIC6659
Faecalibacterium prausnitzii_C
Faecalibacterium prausnitzii_C
KLE1615 sp900066985
Odoribacter splanchnicus
Parabacteroides distasonis
Parabacteroides merdae
Roseburia inulinivorans
Roseburia inulinivorans
Ruminococcus_A sp003011855
UBA1417 sp003531055

How results are calculated

All microbiome marker results are compared against the Microba Healthy Cohort — a purpose-built group of more than 450 healthy individuals, with samples 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. Pedersen, H. K. et al. Human gut microbes impact host serum metabolome and insulin sensitivity. Nature 535, 376 (2016).
2. Hamaya, R. et al. Association of Plasma Branched-Chain Amino Acid With Biomarkers of Inflammation and Lipid Metabolism in Women. Circulation: Genomic and Precision Medicine 14, e003330 (2021).
3. Palmer, N. D. et al. Metabolomic Profile Associated With Insulin Resistance and Conversion to Diabetes in the Insulin Resistance Atherosclerosis Study. https://dx.doi.org/10.1210/jc.2014-2357.
4. Newgard, C. B. et al. A Branched-Chain Amino Acid-Related Metabolic Signature that Differentiates Obese and Lean Humans and Contributes to Insulin Resistance. Cell Metabolism 9, 311–326 (2009).
5. Draper, C. F. et al. A 48-Hour Vegan Diet Challenge in Healthy Women and Men Induces a BRANCH-Chain Amino Acid Related, Health Associated, Metabolic Signature. Molecular Nutrition & Food Research 62, 1700703 (2018).
6. Procházková, N. et al. Gut physiology and environment explain variations in human gut microbiome composition and metabolism. Nat Microbiol 9, 3210–3225 (2024).
7. Lankinen, M. et al. Dietary carbohydrate modification alters serum metabolic profiles in individuals with the metabolic syndrome. Nutrition, Metabolism and Cardiovascular Diseases 20, 249–257 (2010).
8. Moazzami, A. A. et al. Metabolomics reveals the metabolic shifts following an intervention with rye bread in postmenopausal women- a randomized control trial. Nutr J 11, 88 (2012).
9. Schmedes, M. et al. The Effect of Lean-Seafood and Non-Seafood Diets on Fasting and Postprandial Serum Metabolites and Lipid Species: Results from a Randomized Crossover Intervention Study in Healthy Adults. Nutrients 10, 598 (2018).
10. Elshorbagy, A. et al. Amino acid changes during transition to a vegan diet supplemented with fish in healthy humans. Eur J Nutr 56, 1953–1962 (2017).
11. Rinott, E. et al. The effects of the Green-Mediterranean diet on cardiometabolic health are linked to gut microbiome modifications: a randomized controlled trial. Genome Med 14, 29 (2022).
12. Ruiz-Canela, M. et al. Plasma branched chain/aromatic amino acids, enriched Mediterranean diet and risk of type 2 diabetes: case-cohort study within the PREDIMED Trial. Diabetologia 61, 1560–1571 (2018).
13. Lee, S. et al. Branched-chain amino acid metabolism, insulin sensitivity and liver fat response to exercise training in sedentary dysglycaemic and normoglycaemic men. Diabetologia 64, 410–423 (2021).
14. Liu, Y. et al. Gut Microbiome Fermentation Determines the Efficacy of Exercise for Diabetes Prevention. Cell Metabolism 31, 77-91.e5 (2020).
15. Stautemas, J. et al. Acute Aerobic Exercise Leads to Increased Plasma Levels of R- and S-β-Aminoisobutyric Acid in Humans. Front. Physiol. 10, (2019).
16. Glynn, E. L. et al. Impact of combined resistance and aerobic exercise training on branched-chain amino acid turnover, glycine metabolism and insulin sensitivity in overweight humans. Diabetologia 58, 2324–2335 (2015).