Evidence Suggests Linoleic Acid Exerts Health Benefits Beyond Cardiovascular Disease: A Brief Review of Clinical and Observational Studies.

PURPOSE OF REVIEW: Questions challenging the healthfulness of diets high in linoleic acid (LA) and seed oils, which are major sources of this essential fatty acid, have recently arisen. These questions are especially relevant to adherents of plant-based diets as their LA intake is higher than the general population. Some maintain that LA increases inflammation and oxidative stress and for these reasons, despite its ability to lower circulating LDL-cholesterol levels when replacing saturated fat, does not lower cardiovascular disease (CVD) risk. Because most of the discussion about LA has focused on CVD, the primary focus of this manuscript is to examine the effects of LA on health outcomes aside from CVD.

RECENT FINDINGS: Interventional and observational studies indicate increasing LA intake lowers risk of CVD. Beyond CVD, possible benefits include preventing hepatic fat accumulation, increasing muscle mass, decreasing risk of skin cancer, decreasing epigenetic aging, increasing the healthspan, and improving cognitive function and decreasing risk of developing neurocognitive disorders. Support for these proposed benefits comes from observational studies and randomized controlled trials (RCTs), although more from the former. The observational evidence is especially robust in the case of cognitive function and neurological disorders, as the results of all but one of the eight recently published cohort studies show LA exposure, as assessed by dietary intake or circulating levels, is supportive of benefit, although much of the data come from analyses of one cohort. While it is premature to conclude that LA intake exerts benefits beyond CVD, evidence is sufficient to warrant that this possibility should be included in discussions about the role of LA and seed oils in the diet. Given the large contribution LA makes to energy intake, particularly among consumers of plant-based diets, research aimed at more definitively determining the range of possible benefits, especially related to cognitive function, is warranted.