Short Chain Fatty Acids Outpace Ketone Oxidation In The Failing Heart

When hearts begin to fail, they struggle to produce the energy they need to function properly. Normally, hearts get most of their energy by burning long-chain fatty acids (the typical fats from our diet), but failing hearts lose this ability due to problems with a key enzyme called CPT1. Scientists have been studying whether alternative fuel sources like ketones - which the body makes during fasting or on very low-carb diets - could help failing hearts meet their energy needs.

This study compared two potential backup fuel sources: ketones and short-chain fatty acids (SCFAs). SCFAs are produced when beneficial gut bacteria ferment fiber in our intestines, creating compounds like butyrate. Using a rat model of heart failure, researchers tested how well failing hearts could use each fuel type for energy production. They found that while both ketones and SCFAs could bypass the damaged fat-burning pathway, the failing hearts were actually 15% more efficient at using SCFAs than ketones.

The findings were consistent in both the animal model and samples from human patients with heart failure. The hearts had adapted by increasing production of specific enzymes needed to process SCFAs, suggesting this pathway becomes more important as heart function declines. Importantly, when hearts used more of these alternative fuels, they relied less on the impaired long-chain fatty acid pathway.

This research highlights an underappreciated connection between gut health and heart health. While this is early-stage research, it suggests that maintaining a healthy gut microbiome through fiber-rich foods - which promotes SCFA production - may eventually prove beneficial for cardiovascular health, particularly in patients at risk for heart failure.