“Seed oils are inflammatory and destroying your health" is one of the loudest nutrition myths right now. The truth? Most of the fear comes from cherry-picked studies and social-media fear-mongering, not solid evidence. Major health organizations still support using unsaturated oils (like canola, sunflower, and soybean) in moderation as…”

On inflammation. A meta-analysis of randomized trials found no signal that raising linoleic acid intake increases inflammatory markers. Thirty randomized controlled studies involving 1,377 subjects were pooled, and no significant effect of higher linoleic acid intake was observed for tumor necrosis factor, interleukin-6, adiponectin, or monocyte chemoattractant protein 1 . An earlier systematic review reached the same conclusion: the authors concluded that virtually no evidence is available from randomized controlled intervention studies among healthy, noninfant humans to show that adding linoleic acid to the diet increases concentrations of inflammatory markers . That review was undertaken specifically to test the mechanism seed oil critics cite, namely the concern that high dietary n-6 polyunsaturated fatty acid intake contributes to excess chronic inflammation by prompting synthesis of proinflammatory eicosanoids derived from arachidonic acid . A more recent biomarker analysis points in the same direction. Higher serum levels of linoleic acid and total omega-6 polyunsaturated fatty acids were associated with lower concentrations of high-sensitivity C-reactive protein and glycoprotein acetyls, both risk factors for cardiovascular events and type 2 diabetes, in findings presented at NUTRITION 2025 and published in Current Developments in Nutrition . The lead investigator described the study as based on almost 1,900 people and found higher plasma linoleic acid associated with lower levels of cardiometabolic risk biomarkers, including inflammation-related ones . Important caveat from the releasing organization itself: abstracts presented at NUTRITION 2025 were evaluated by a committee of experts but have not generally undergone the same peer review process required for journal publication . On cholesterol and cardiovascular outcomes. The AHA's formal position is explicit. The 2017 Presidential Advisory reviewed the scientific evidence on dietary saturated fat and cardiovascular disease and strongly concluded that reducing saturated fat intake and replacing it with unsaturated fat, especially polyunsaturated fat, will reduce the rate of cardiovascular disease. Randomized controlled trials that lowered saturated fat intake and replaced it with polyunsaturated vegetable oil reduced cardiovascular disease by approximately 30 percent, similar to the reduction achieved by statin treatment, and prospective observational studies showed lower saturated fat intake coupled with higher polyunsaturated and monounsaturated fat intake associated with lower rates of disease. The same advisory also addressed the specific swap the post warns about: coconut oil increases cholesterol . Cochrane's independent synthesis is consistent. The review found that health benefits arose from replacing saturated fats with polyunsaturated fat or starchy foods, and that the greater the decrease in saturated fat and the more serum total cholesterol was reduced, the greater the protection from cardiovascular events. The authors assessed replacement of animal fats and hard vegetable fats with plant oils, unsaturated spreads, or starchy foods for at least two years, in adults with and without cardiovascular disease , and included 15 studies with more than 59,000 participants . On the organizational-position element. The American Heart Association states there is no evidence suggesting seed oils should be avoided, and points to evidence that they are beneficial . An AHA expert quoted in its own news coverage put the emphasis on overall diet: the real concern should be overeating ultra-processed foods, which may contain harmful ingredients such as high-fructose corn syrup, added sugar and sodium, and it is hard to blame the seed oils when these foods contain so many other things . He added that if people use seed oils to cook or complement otherwise healthy meals, such as stir-frying vegetables or lightly dressing a salad, the benefits far outweigh any potential health risks . Counter-evidence that the post does not acknowledge. Recovered data from an old randomized trial complicate the outcome story. In the Minnesota Coronary Experiment, the intervention group replacing saturated fat with linoleic acid from corn oil had a significant reduction in serum cholesterol compared with controls, but Kaplan Meier graphs showed no mortality benefit in the full randomized cohort or any prespecified subgroup . The authors concluded that available randomized trial evidence shows replacement of saturated fat with linoleic acid effectively lowers serum cholesterol but does not support the hypothesis that this translates to lower risk of death from coronary heart disease or all causes, and that incomplete publication has contributed to overestimation of the benefits . A related reanalysis of the 1960s Sydney Diet Heart Study reported that volunteers who replaced much of their saturated fat with linoleic-acid-rich polyunsaturated fat had a higher risk of coronary heart disease death .