To a large extent our well-being depends on what bacterial guests in our digestive tract consume as researchers have found that beneficial gut microbes can produce from dietary fibre a fatty acid called propionate which can protect against the harmful consequences of high blood pressure.

The substance calms the immune cells that drive up blood pressure, according to the study published online in the journal Circulation. "Propionate works against a range of impairments in cardiovascular function caused by high blood pressure," said lead researcher Dominik Muller, Professor at Max Delbrück Center for Molecular Medicine in the Helmholtz Association in Berlin, Germany.

"This may be a promising treatment option, particularly for patients who have too little of this fatty acid," Muller said. The results explain why a diet rich in fibre, which has been recommended by nutrition organisations for many years, helps prevent cardiovascular diseases. 

Whole-grain products and fruits, for example, contain cellulose and inulin fibers, from which gut bacteria produce the beneficial molecules like propionate. For the study, the researchers fed propionate to mice with elevated blood pressure. Afterwards, the animals had less pronounced damage to the heart or abnormal enlargement of the organ, making them less susceptible to cardiac arrhythmia. Vascular damage, such as atherosclerosis, also decreased in mice, the study said.