How Blocking an Omega-3 Processing Enzyme Affects Muscle Breakdown in Mice

This mouse study looked at how the body’s enzyme for processing omega-3 and omega-6 fats (called delta-6-desaturase, or FADS2) influences muscle protein turnover — the balance between building and breaking down muscle tissue. Researchers fed mice either a high-fat diet rich in omega-6 fats (lard-based) or one rich in omega-3 fats (fish oil-based), with or without a drug that blocked the FADS2 enzyme.

Blocking FADS2 did not change signals related to muscle protein synthesis. However, it did increase markers linked to muscle protein breakdown, including higher autophagy activity (a cellular ‘clean-up’ process) and trends toward increased markers of protein degradation, regardless of which diet the mice were fed.

The researchers concluded that the muscle-protective effects sometimes seen with omega-3 fats may work mainly by reducing muscle breakdown rather than by boosting muscle building. When the enzyme needed to convert omega-3 building blocks into their active forms was blocked, this protective effect against muscle breakdown was lost.