A Gut Microbe's Fatty Acid Halved Artery Plaque in Mice

Jeff's Daily Pick. A common gut bacterium makes a fatty acid that hits the same liver enzyme as statins. In mice, it cut artery plaque in half.

In China, researchers at Sun Yat sen University and the Shenzhen Bay Laboratory published a study in Nature on October 7, 2026 showing how a common human gut bacterium, Bacteroides uniformis, protects mice against atherosclerosis. Bacteroides species are depleted in patients with atherosclerosis, but whether they play a causal role had been unclear.

From microbe to molecule

The team used male mice genetically prone to clogged arteries and fed a high fat diet. Live B. uniformis given for 12 weeks shrank plaque in the main artery by about one third compared with untreated mice, lowered total and LDL cholesterol, and reduced inflammatory immune cells in the artery walls. Heat killed bacteria did not have the same effect. Screening the bacterium's products for activity led to one compound: pentadecanoic acid, a saturated fatty acid with an odd number of carbons, known as C15:0.

A statin like mechanism

Given directly three times a week for eight weeks, pentadecanoic acid reduced plaque burden by around 50% and improved blood lipids. It directly inhibited HMG-CoA reductase, the liver enzyme blocked by statins, which suppressed cholesterol synthesis in the liver, raised LDL receptor expression and sped up removal of LDL cholesterol from the blood. Atorvastatin was slightly stronger at the same dose, according to coverage of the paper. Among 100 gut bacterial strains tested, production of the fatty acid occurred across multiple Bacteroidota genera, and its levels were markedly lower in patients with dyslipidaemia.

Pentadecanoic acid has mostly been studied as a marker of dairy intake. This work adds a second source, the microbiome, and a mechanism. It also explains why its blood levels might track heart risk. The next questions are whether people's levels depend on their gut bacteria and whether raising them lowers LDL in a trial. Our piece on another route to lower cardiovascular risk covers a drug already in late stage testing.