Researchers have identified 50 bacterial species strongly associated with markers of good health in the gut microbiome, based on data from over 34,000 people. The findings highlight links to cholesterol control, reduced inflammation, and better blood sugar management. This work aims to define what constitutes a healthy microbial community amid ongoing debates over its composition.
A large-scale analysis of gut microbiomes from more than 34,500 participants in the PREDICT program, conducted in the UK and US by Zoe, has pinpointed specific bacteria tied to health outcomes. The study, published in Nature, focused on 661 bacterial species present in over 20 percent of participants. Among these, 50 species—22 newly identified—correlate with positive health indicators, including lower cholesterol levels, reduced inflammation, healthier immune function, better body fat distribution, and improved blood sugar control.
Healthy individuals without known medical conditions hosted about 3.6 more of these beneficial species compared to those with conditions. Similarly, people at a healthy weight had roughly 5.2 more such species than those with obesity. The research suggests these microbes influence health by producing chemicals that aid cholesterol transport, curb inflammation, metabolize fats, and enhance insulin sensitivity.
Most of the beneficial and harmful bacteria belong to the Clostridia class, particularly the Lachnospiraceae family, with 13 species showing favorable effects and 27 unfavorable ones. Nicola Segata at the University of Trento in Italy, who led the work, noted: “There is a very intricate relationship between the food we eat, the composition of our gut microbiome and the effects the gut microbiome has on our health. The only way to try to map these connections is having large enough sample sizes.”
Dietary patterns were also examined through questionnaires and Zoe app data, recommending at least 30 different plants weekly, three daily portions of fermented foods, high fiber intake, and minimal ultra-processed items. While most microbes aligned with healthier or poorer diets, 65 did not, underscoring the complexity. Segata added: “These 65 bacteria are a testament to the fact that the picture is still more complex than what we saw.”
The team developed a 0-to-1000 scale to rank gut microbiome health, now integrated into Zoe's tests. Tim Spector at King’s College London, a co-founder of Zoe, explained: “Think of a healthy gut microbiome as a community of chemical factories. We want large numbers of species, we want the good ones outnumbering the bad ones, and when you get that, then you’re producing really healthy chemicals, which have impacts across the body.”
Experts like Ines Moura at the University of Leeds caution that defining a healthy microbiome remains challenging due to influences from diet, environment, age, and medications. Larger global studies are needed to refine these insights and potentially guide personalized dietary recommendations.
