Summary:
Cardiometabolic diseases (CMDs), including cardiovascular disease and type 2 diabetes, remain major contributors to illness and death in Western countries. Dietary patterns are recognised as key modifiable factors influencing CMD risk, particularly the increased intake of highly processed, energy-dense foods. Traditional indicators used to examine CMD risk, such as blood pressure, lipid profiles, glucose measures, inflammatory biomarkers, and body mass index, capture important clinical information but do not reflect biological processes occurring within the gut. The gut microbiome has increasingly been recognised as an important, modifiable factor linking diet and cardiometabolic health. Dietary changes can alter the composition of gut microbial species, which may in turn influence host physiology. However, responses to dietary interventions vary widely between individuals, and the microbiome itself differs substantially according to demographics such as age, sex, ethnicity, and lifestyle. This study was a large-scale cross-sectional analysis with an interventional component, aimed at identifying gut microbiome species that are consistently associated with diet quality and cardiometabolic health markers across large, diverse populations. The dataset included more than 34,000 participants from the United States and the United Kingdom. Across cohorts, this study identified microbial species that were consistently associated with more favourable or unfavourable cardiometabolic profiles. In a further sample of 746 participants enrolled in two dietary intervention trials, species classified as favourable increased in abundance over time, whereas unfavourable species declined. Overall, this study provides robust associative evidence linking dietary patterns, gut microbiome composition, and cardiometabolic health markers. However, the authors note that causal relationships cannot be established without further prospective cohort studies and controlled clinical trials.
Abstract:
The incidence of cardiometabolic diseases is increasing globally, and both poor diet and the human gut microbiome have been implicated1. However, the field lacks large-scale, comprehensive studies exploring these links in diverse populations2. Here, in over 34,000 US and UK participants with metagenomic, diet, anthropometric and host health data, we identified known and yet-to-be-cultured gut microbiome species associated significantly with different diets and risk factors. We developed a ranking of species most favourably and unfavourably associated with human health markers, called the ‘ZOE Microbiome Health Ranking 2025’. This system showed strong and reproducible associations between the ranking of microbial species and both body mass index and host disease conditions on more than 7,800 additional public samples. In an additional 746 people from two dietary interventional clinical trials, favourably ranked species increased in abundance and prevalence, and unfavourably ranked species reduced over time. In conclusion, these analyses provide strong support for the association of both diet and microbiome with health markers, and the summary system can be used to inform the basis for future causal and mechanistic studies. It should be emphasized, however, that causal inference is not possible without prospective cohort studies and interventional clinical trials.
Article Publication Date: 10/12/2025
DOI: 10.1038/s41586-025-09854-7
