Gut Microbe Molecule Lowers Cholesterol and Arterial Plaque
Watching the Arteries from Orbit
Atherosclerosis is quiet. Fatty plaque builds up in the walls of arteries, narrowing the channel that blood must pass through, and for years the person carrying it feels nothing. Atherosclerosis, the progressive buildup of inflammatory plaques in artery walls, remains the leading cause of death globally. Statins, the drugs designed to lower cholesterol and ward off cardiovascular disease, are prescribed to hundreds of millions of people worldwide.
Now a study published in Nature on 7 October 2026 reports that a bacterium commonly found in the human gut, Bacteroides uniformis, manufactures a molecule capable of cutting cholesterol levels and shrinking arterial plaque in mice. [2] The compound is pentadecanoic acid, a saturated odd-chain fatty acid with fifteen carbon atoms. When administered to mice genetically engineered to develop atherosclerosis and fed a high-fat diet, the molecule reduced plaque burden in the main arteries by roughly half. The bacterial dose itself — live B. uniformis given to the animals — shrank plaques by about one-third compared with untreated mice. The bacterial dose also lowered total cholesterol and low-density lipoprotein, the so-called bad cholesterol, and reduced the number of inflammatory immune cells infiltrating the rodents’ arterial walls.
The finding matters because statins, for all their success, fail to reduce cholesterol sufficiently in nearly half of people with advanced heart disease. Some patients cannot tolerate high doses of the drugs at all. An alternative route to the same biological destination — one that arrives via the gut rather than the pharmacy — would change the arithmetic of cardiovascular prevention.
The Enzyme That Cannot Be Faked
The mechanism is where the story sharpens. Pentadecanoic acid inhibits HMG-CoA reductase, a liver enzyme involved in cholesterol production. That is the same enzyme statins target. Blocking it triggers the liver to generate more LDL receptors, which in turn pull excess cholesterol out of the bloodstream.
Wenjing Zhao, a microbiologist at Sun Yat-sen University in Shenzhen, China, and her colleagues did not stumble onto this molecule by chance. They first analysed gut flora in stool samples from people with and without cardiovascular disease. One species stood out: B. uniformis. Levels of the bacterium were often depleted in those with heart disease compared with healthy individuals. That observation alone would have been a correlation. The team went further, isolating the molecule driving the protection and showing its action in living animals.
Ben Chen, a cardiovascular specialist at Monash Victorian Heart Institute in Melbourne, Australia, called the work “valuable evidence that the gut microbiome can influence vascular health,” moving beyond a simple link between heart disease and the microbiome and towards “evidence for a potentially causal biological mechanism.” [2] Whether the mouse results will hold in humans is not yet known. The study examined blood and stool samples from more than 200 human donors and found that people with abnormally high concentrations of fatty molecules such as cholesterol in their blood had lower levels of pentadecanoic acid than healthy individuals. [2] Stool analyses also showed that people with heart disease carried fewer bacterial genes dedicated to manufacturing the molecule than did the control group. These are associations in human tissue, not outcomes from a human trial. The causal chain — bacterium produces molecule, molecule inhibits enzyme, enzyme blockade clears cholesterol, plaque shrinks — has been demonstrated in mice. Whether that chain runs unbroken in people remains the open question.
A Door That
Opens from the Gut
The molecule’s production has been linked to B. uniformis in this study; whether other bacteria can produce it as well is not established here. This is not necessarily a single microbe’s trick, but the present work does not show that the capability is distributed across a broader family of bacteria. It remains an open question whether the molecule’s presence or absence in a person’s gut depends on one species alone or on a wider microbial neighbourhood.
The finding sits at the intersection of two fields that have been circling each other for years: cardiovascular medicine and microbiome research. The first has mastered the chemistry of cholesterol lowering through statins but hit a ceiling in patients who cannot tolerate them or whose cholesterol remains stubbornly high. The second has produced a stream of correlations linking gut bacteria to heart disease, cancer therapy response, chronic pain, and memory loss in ageing mice — but far fewer causal mechanisms. This study offers one such mechanism, with a named molecule and a mapped enzyme target.
A bacterium already living in many human guts appears to run a cholesterol-lowering programme that mirrors the most successful class of cardiovascular drugs ever developed. The therapeutic potential lies in modulating the microbial-metabolic axis — the chain of signals that runs through the gut, the liver, the bloodstream, and the walls of the arteries themselves.
