Researchers conducted a controlled dietary intervention study involving 52 healthy adults to see how different amounts of linoleic acid (LA) in the diet affect the body. Participants were divided into two groups: one ate a high LA diet providing 10.0% of their energy from LA, while the other ate a low LA diet with only 2.5% energy from LA. They followed the participants for 12 weeks to measure changes in plasma fatty acids and how their blood cells produced certain chemical signals when stimulated.
The main results showed that the high LA diet led to a marked reduction in plasma n-3 eicosapentaenoic acid (EPA) concentrations compared to the low LA group. Additionally, the production of EPA-derived oxylipin mediators relative to ARA-derived ones was significantly reduced in the high LA arm. However, levels of arachidonic acid, dihomo-gamma-linolenic acid, and docosahexaenoic acid did not differ between the two dietary groups.
No adverse events, serious adverse events, discontinuations, or specific tolerability issues were reported during the study. The main reason to be careful is that this was a small study with a limited sample size, and direct evaluations of the biological consequences of varying LA exposure remain limited in this type of research. Readers should take from this that while a link was observed, larger and longer studies are required before drawing firm conclusions about the health impacts of high LA diets.