“Consumption of seed oils causes chronic inflammation and disease in humans.”

Two systematic reviews of RCTs demonstrated that higher intake of LA did not increase or had no effect on inflammatory markers. Oxidation of PUFAs has been demonstrated in both in vitro and ex vivo studies, however, RCTs show no effect of omega-6 or PUFA on oxidative stress markers. Current scientific literature supports incorporating seed oils into a well-rounded diet, particularly as an alternative to saturated fat. Although some debates persist around their potential inflammatory or oxidative effects, the majority of peer-reviewed studies do not support these concerns when seed oils are consumed in typical dietary amounts.

Epidemiological evidence indicates that higher PUFA intake is associated with lower risk of incident CVD and type 2 diabetes mellitus (T2DM). In RCT examining diets lower in SFA that included high-PUFA oils, clinically relevant reductions in CVD events have been observed. In the most recent (2020) Cochrane Review, which included thirteen RCT (sixteen comparisons, 53 758 participants, mean duration 4·7 years), reducing SFA intake lowered the risk of combined cardiovascular events by 17 % (RR 0·83; 95 % CI 0·70, 0·98), and the quality of evidence was assessed as moderate.

We conclude that virtually no evidence is available from randomized, controlled intervention studies among healthy, noninfant human beings to show that addition of LA to the diet increases the concentration of inflammatory markers.

"Every study for decades has shown that when you eat unsaturated fats instead of saturated fats, this lowers the level of LDL cholesterol in your blood," Gardner said. "There are actually few associations in nutrition that have this much evidence behind them." Large studies tracking tens or hundreds of thousands of people over decades (including one published this month) have found associations between eating more unsaturated fats — and less saturated fats — and lower death rates.

“The idea that omega-6 fatty acids are pro-inflammatory is propagated over and over again in social media,” said Willett, professor of epidemiology and nutrition. “Dozens of studies have looked at this, and about half of them show no effect, while the other half show reduction in inflammatory factors.” Evidence suggests that foods containing omega-6 can help lower cholesterol and blood sugar and reduce heart disease risk. The bottom line from Willett: “Seed oils are basically a very healthy part of a diet, and when you look at some of the alternatives—like butter or lard—these are much better.”

New research that used blood markers to measure linoleic acid levels and their relation to cardiometabolic risk adds evidence that this omega-6 fatty acid may help to lower risks for heart disease and type 2 diabetes. The findings challenge claims that seed oils are harmful to cardiometabolic health.

Seed oils are high in linoleic acid, a type of omega-6 fatty acids... This type of imbalance is thought to lead to inflammation in the body... chronic inflammation is definitely not. It’s linked to conditions like: Arthritis, Heart disease, Metabolic syndrome, Stroke, Type 2 diabetes. Again, this doesn’t mean seed oils cause chronic conditions, per se. But a diet high in seed oils can play a role in skewing your body’s delicate balance of omega-6s and omega-3s. This can then contribute to inflammation, which can lead to chronic conditions.

Most human clinical trials and epidemiological research do not support a direct link between moderate seed oil consumption and chronic inflammation. One of the most common arguments against seed oils is that they may be inflammatory. However, this claim is based mainly on animal studies or outdated data. Most human clinical trials and epidemiological research do not support a direct link between moderate seed oil consumption and chronic inflammation.

However, current evidence does not show that seed oils cause this type of long-term inflammation. There is a lack of conclusive evidence that seed oils increase inflammation and raise the risk of cardiovascular disease.

Most seed oils have a much higher amount of omega-6 fatty acids compared to omega-3s. However, there is a lack of research to suggest that omega-6 fatty acids cause inflammation.

However, current research from randomised controlled trials show that this isn't the case. These studies show that adding linoleic acid (a common omega-6 fatty acid, abundant in seed oils) to the diet doesn't increase the concentration of inflammatory markers.

“These new data show clearly that people who have the highest levels of LA (and AA) in their blood are in a less inflammatory state than people with lower levels. This finding is exactly the opposite of what one would expect if omega-6 fatty acids were 'proinflammatory' – in fact, they appear to be anti-inflammatory,” explained study investigator William S.

Evidence generated over the past decade shows linoleic acid intake is associated with lower risk of chronic disease and is not pro-inflammatory. The American Heart Association reported in 2017 that little direct evidence supports the notion that linoleic acid is pro-inflammatory, and a host of other organizations agree that the ratio of omega-6 to omega-3 fat is not a useful indicator.

A common concern about seed oils is that they lead to unhealthy inflammation because they contain omega-6 fatty acids. In the right amount, omega-6 fatty acids contribute positively to our health. Research shows that omega-6 fatty acids help lower LDL, or harmful cholesterol, and are protective against heart disease. This does not mean that omega-6’s on their own are harmful, just that we don’t need too many of them.

A spring 2025 article summarizing findings from a review of observational studies and clinical trials found consistent evidence that higher intake of unsaturated fats, which are found in these seed oils, is associated with lower risk of cardiovascular disease and type 2 diabetes. The concern that omega-6 fatty acids cause chronic inflammation is rooted in a simplification of metabolism and not supported by overall evidence.

High consumption of omega-6 fatty acids, as found in abundance in industrial seed oils, has been linked to inflammatory diseases, including cardiovascular ailments. Research now suggests that this imbalance contributes to the development of chronic inflammatory diseases.

While arachidonic acid (ARA) is a precursor to pro-inflammatory mediators, studies in healthy human adults have found that increased intake of ARA or linoleic acid (LA) does not increase the concentrations of many inflammatory markers. Epidemiological studies have even suggested that ARA and LA may be linked to reduced inflammation.

While the internet may be full of posts stating that seed oils such as canola and soy are “toxic,” scientific evidence does not support these claims, according to experts. It's true that many foods that use seed oils—such as packaged snacks and french fries—are unhealthy, but they also tend to be high in refined carbohydrates, sodium, and sugar.

No strong evidence shows that seed oils cause inflammation in humans; multiple reviews of RCTs find linoleic acid does not increase inflammatory markers and may reduce CVD risk when replacing saturated fats.

This systematic review evaluates the impact of seed oils on lipid profiles, inflammatory and oxidative markers, and glycemic control in patients with diabetes and dyslipidemia. Seed oils, such as those derived from sunflower, safflower, and canola seeds, are often touted for their favorable fatty acid composition, including high levels of Polyunsaturated Fatty Acids (PUFAs), which are believed to influence lipid profiles and other metabolic markers positively.

This extreme elevation in omega-6 fatty acid levels has a wide-spread, pro-inflammatory effect on all systems of the body and is associated with a long list of health issues, including asthma, autoimmune disease, depression, anxiety, Alzheimer's, diabetes, obesity, heart disease, digestive disorders such as IBS and IBD, infertility in both men and women, osteoarthritis and more.

Major health organizations including the WHO, American Heart Association, and dietary guidelines from the USDA consistently recommend replacing saturated fats with polyunsaturated fats from seed oils like canola and soybean for reducing cardiovascular risk, based on meta-analyses of RCTs showing no increase in inflammation markers from omega-6 intake.