Omega 6 fatty acids: helpful, harmless or harmful?

Purpose of review: This paper reviews the most recent literature from January 2023 to August 2024 on the physiological effects of n-6 polyunsaturated fatty acids (PUFAs), with a focus on linoleic acid (LA).

Recent findings: Contrary to previous concerns that high LA intake may increase inflammation, most recent evidence supports the benefits of LA for cardiometabolic health. Several large studies report that higher blood LA levels correlate with reduced risks of coronary heart disease, stroke, and type 2 diabetes. Potential mechanisms include activation of peroxisome proliferator-activated receptors and modulation of oxylipins involved in glucose and lipid metabolism. The ideal LA intake level remains uncertain, but current intakes around 5-10% of energy appear beneficial. In other areas like cancer, asthma and sleep, the evidence is still inconclusive on LA's effects.

Summary: More research on diverse populations is needed to determine optimal LA levels, effects on specific conditions, and interactions with genetic factors affecting PUFA metabolism. Overall, the review highlights the emerging view that LA, the primary dietary n-6 PUFA, has cardiometabolic benefits rather than harmful effects.