Researchers reported on October 7, 2026, that the gut bacterium Bacteroides uniformis and a fatty acid it produces reduced cholesterol levels and atherosclerotic plaque in mice.
The study, published in Nature, identified pentadecanoic acid, also known as C15:0, as the molecule chiefly responsible for the effect. In experiments, mice given B. uniformis developed less plaque, while animals receiving the fatty acid showed a reduction in plaque burden of about 50%. The compound appeared to inhibit HMG-CoA reductase, a liver enzyme involved in cholesterol production and the same target blocked by statin drugs.
That inhibition increased the liver’s production of LDL receptors, helping remove “bad” cholesterol from the bloodstream. Researchers also found lower levels of the bacterium or its fatty acid among some people with cardiovascular disease or abnormal blood-fat levels. However, those human findings were observational and did not prove that the microbe prevents heart disease.
The researchers said further studies, including clinical trials, are needed before the discovery can be considered a treatment for people.