February 16, 2026, 10:08 am | Read time: 3 minutes
The composition of the gut microbiome is closely linked to the quality of one’s diet. It influences which gut bacteria settle and how stable these communities are. A comprehensive study systematically examines how diet, gut bacteria, and selected health markers are interconnected.
What Was Examined in the Study?
A large-scale study published in the journal “Nature” investigated the relationship between diet, gut microbiome, and health markers in 34,694 adults from the U.S. and the U.K.1 The bacteria detectable in the gut were analyzed. Additionally, researchers evaluated detailed dietary records, body measurements, and blood values. The goal was to categorize gut bacteria based on how favorably or unfavorably they statistically correlate with established health markers. This resulted in a ranking that assesses bacteria based on whether they are more common in people with better or worse health values. The results were further verified in independent datasets and two controlled dietary intervention studies.
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The Results
The analysis revealed consistent patterns of how certain gut bacteria are associated with diet and health characteristics.
The researchers identified 661 bacterial species commonly detectable in the gut, which were linked to health values to varying degrees.
- Favorably rated bacterial species were more common in people with a lower body mass index, better blood lipid levels, more stable blood sugar, and lower inflammation levels.
- Unfavorably rated bacterial species were more prevalent in external comparison datasets among people with overweight or obesity, type 2 diabetes, cardiovascular diseases, and inflammatory bowel diseases.
- People with normal body weight had, on average, 5.2 more species from the group of the 50 most beneficial bacteria than those with obesity.
- In two controlled dietary intervention studies with a total of 746 participants, the gut microbiome changed measurably. Favorably rated bacteria increased, while unfavorably rated ones decreased. These changes occurred especially when the diet became richer in fiber, included greater plant diversity, and the overall quality of the diet improved.
- Many of the particularly positively rated bacterial species are still scarcely researched scientifically and have not yet been cultivated in the lab.
What Does the Study Mean?
The study shows that the gut microbiome is closely linked to diet and important health values. The newly developed ranking by ZOE, a company for personalized nutrition, systematically categorizes gut bacteria according to their statistical health relevance, without directly proving cause and effect. At the same time, the intervention studies demonstrate that the microbiome can be measurably shifted in a favorable direction through a fiber-rich, overall higher-quality diet, while the tested probiotic supplementation did not show a comparably consistent effect. The ranking can help better classify dietary strategies and further develop personalized approaches.
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