A landmark study involving over 34,000 individuals from the UK and US has mapped hundreds of gut microbial species to dietary habits and cardiometabolic health.
Researchers combined metagenomic sequencing with detailed health and nutrition data to create the ZOE Microbiome Health Ranking 2025, which classifies microorganisms as favorable or unfavorable based on their associations with markers like BMI.
When tested on 7,800 independent samples, individuals with higher abundances of favorably ranked species had healthier metabolic profiles; those with unfavorably ranked microbes were more likely to have obesity and cardiometabolic risk factors.
Separate dietary intervention trials in 746 participants showed that dietary changes can increase favorable species and reduce unfavorable ones over time.
The findings, published in Nature, establish strong links between diet, the gut microbiome, and health, though they do not prove causation. The ranking system offers a tool for prioritizing microbes in future clinical research.