Dietary mono-unsaturated fatty acids can extend lifespan in nematode worms, suggests a Nature paper published online this week. Further research is required to determine whether these findings could have implications for human health and lifespan.

H3K4me3 methyltransferase is an enzyme involved in histone modification, an epigenetic phenomenon whereby environmental signals are able to influence gene expression. It is already known that H3K4me3 methyltransferase deficiency extends lifespan in nematodes, but the mechanism responsible was unknown. Anne Brunet and colleagues show that the same enzymatic deficiency alters fat metabolism in worms, promoting the build-up of mono-unsaturated fatty acids (MUFAs) in the intestine. This led to the discovery that dietary supplementation with MUFAs, such as oleic or palmitoleic acid, can enhance longevity in worms.

Fat metabolism plays an important role in many physiological and pathological processes. In humans, excessive storage of fat in the form of triglycerides is associated with diseases such as atherosclerosis and type 2 diabetes, but emerging studies are beginning to challenge the idea that increased fat storage is unhealthy in all cases. MUFAs are readily found in many food sources, including red meat, nuts, olives and avocados, and MUFA-rich diets have been linked to a decreased risk for cardiovascular disease and diabetes in humans. However, additional studies are needed to properly assess the benefits of MUFAs in humans.