In a randomized crossover feeding trial, contrasting dietary patterns (Healthy Australian Diet vs. Typical Australian Diet) remodeled gut microbial function and generated multi-omic signatures associated with cardiometabolic markers, with integrated microbiome-metabolome profiling achieving 91.7% held-out accuracy in discriminating dietary responses.
Key Findings
Results
The Healthy Australian Diet (HAD) was associated with reduced taxonomic and functional alpha diversity relative to baseline, while the Typical Australian Diet (TAD) produced no change in alpha diversity.
Study involved 34 Australian adults in a randomized crossover feeding trial
Each dietary period lasted two weeks, separated by a two-week washout period
HAD was aligned with national dietary guidelines; TAD reflected average population intake
Fecal microbiome composition and function were assessed using shotgun metagenomics
Results
Species-level microbial responses to the contrasting diets were modest.
Despite changes in alpha diversity under HAD, species-level taxonomic differences between diets were described as modest
Shotgun metagenomics was used to characterize both composition and function
The crossover design allowed within-individual comparisons of dietary effects
Results
105 functional microbial pathways differed between the two dietary patterns, with 99 increasing following HAD.
Pathways upregulated under HAD were predominantly related to amino acid and nucleotide biosynthesis and vitamin/cofactor metabolism
Only 6 of the 105 differing pathways were not increased following HAD
Functional profiling was conducted using shotgun metagenomics
Results
Multi-omic integration using DIABLO achieved strong discrimination between dietary responses.
Held-out classification accuracy was 91.7%
Permutation p-value = 0.005
Integration combined fecal microbiome, plasma metabolomics, and urine metabolomics data
Plasma and urine metabolites were assessed by untargeted metabolomics
Associations spanned microbial gene functions, plasma metabolites, and urinary metabolites
Cardiometabolic outcomes included cholesterol, blood pressure, and triglyceride responses
Cardiometabolic markers quantified included blood pressure, plasma lipids, and glucose
Conclusions
Integrated microbiome-metabolome profiling may capture inter-individual variation in dietary cardiometabolic responses, but replication is needed before translational applications.
Authors describe findings as 'exploratory'
Replication in 'larger, independent, robustly designed studies is needed before translational personalized nutrition strategies can be assessed'
The study included only 34 participants and two weeks per dietary period
The crossover design with washout period was used to control for individual variation
What This Means
This research suggests that switching between a healthy diet (aligned with Australian dietary guidelines) and a typical Western-style diet (reflecting average Australian intake) produces measurable changes in the gut microbiome and in the chemical compounds found in blood and urine. In a study where 34 adults followed each diet for two weeks, researchers found that the healthy diet was associated with a reduction in the diversity of gut microbes, but also with increases in 99 microbial functional pathways — particularly those related to producing amino acids, nucleotides, and vitamins. The typical diet produced fewer detectable changes in gut microbial activity.
When researchers combined data from gut microbiome analysis, blood metabolites, and urine metabolites together using an advanced statistical method, they could correctly identify which diet a person had been following with 91.7% accuracy. They also found 77 statistically significant links between specific microbial or metabolic features and cardiometabolic health markers like cholesterol levels, blood pressure, and triglycerides.
This research suggests that analyzing the gut microbiome and metabolites together — rather than separately — may help explain why people respond differently to the same diet in terms of heart and metabolic health. However, the authors caution that these are exploratory findings from a small, short-term study, and that much larger independent studies are needed before this type of profiling could be used to develop personalized dietary advice for improving cardiometabolic health.
Stanford J, Hoedt E, Gómez-Martín M, Clarke E, Duncanson K, Burrows T, et al.. (2026). Contrasting dietary patterns remodel gut microbial function and generate multi-omic signatures associated with cardiometabolic markers.. Gut microbes. https://doi.org/10.1080/19490976.2026.2685381