A Seed of Truth

Seed oils have been demonized by politicians and health influencers alike for the past several months. But recent research suggests switching to beef tallow for French fries may have been done a bit prematurely.

New research finds that a fat found in seed oil known as linoleic acid is associated with lower levels of inflammation. Seed oils may have a real health benefit despite being painted as harmful.

The new study used blood markers to evaluate linoleic acid levels and their link to cardiometabolic risk. It adds proof that the omega-6 fatty acid may aid in lowering risks for heart disease and type 2 diabetes.

Found in plant foods and vegetable oils, including soybean and corn oil, linoleic acid is the primary omega-6 fatty acid eaten in the diet.

Kevin C. Maki, Ph.D., adjunct professor at the Indiana University School of Public Health-Bloomington and chief scientist at Midwest Biomedical Research notes, "There has been increasing attention on seed oils, with some claiming these oils promote inflammation and raise cardiometabolic risk," said. "Our study, based on almost 1,900 people, found that higher linoleic acid in blood plasma was associated with lower levels of biomarkers of cardiometabolic risk, including those related to inflammation."

Maki presented the findings at NUTRITION 2025, the flagship annual meeting of the American Society for Nutrition held in Orlando, Florida.

This new evidence is aligned with those from previous observational studies that have shown that higher intake of linoleic acid is linked with lower risks for type 2 diabetes and cardiovascular problems like heart attacks and strokes.

Maki states, "Although other studies have assessed relationships between linoleic acid and cardiometabolic risk factors, our study used objective biomarkers rather than diet records or food frequency questionnaires to assess linoleic acid intake. We also measured a range of markers of inflammation and indicators of glucose metabolism."

The researchers conducted a cross-sectional analysis using data from nearly 1,900 individuals in the observational cohort focused on COVID-19. Higher levels of linoleic acid in plasma (associated with dietary intake) were consistently linked with reduced risk factors for type 2 diabetes and cardiovascular disease.

Study subjects with higher linoleic acid had lower glucose and insulin levels, in addition to HOMA-IR, an insulin resistance biomarker. Inflammation biomarkers such as C-reactive protein, glycoprotein acetyls, and serum amyloid A were also lower.

"We saw consistent results across the different biomarkers measured," Maki said. "People with higher levels of linoleic acid in their blood tended to have a healthier overall risk profile for heart disease and diabetes."

The researchers note that their study supports the need for more interventional studies to evaluate whether increasing linoleic acid consumption improves cardiometabolic risk factors and lowers the rate of heart attacks, strokes, and type 2 diabetes. They plan to investigate how various types of oils with different fatty acid content impact cardiometabolic risk factors.

To protect yourself from cardiometabolic conditions:

·         Ignore the nutrition noise about seed oils. It’s based on fear, not facts.

·         Limit consumption of ultra-processed foods like snacks and pastries and fast food.

·         Use a variety of oils when you cook, including avocado, canola, olive, and soybean.

·         Limit use of solid fats like butter, lard, beef tallow, and margarine.

·         Eat a diet heavy in plants, including a variety of fruits, vegetables, legumes, whole grains, nuts, and seeds.

·         Reduce intake of red meat, including beef, lamb, and pork.

·         Be mindful of serving sizes to keep calories in check.

·         Adopt a regular exercise routine.

·         Don’t smoke or use other tobacco products.

·         Avoid sugar-sweetened beverages and excess added sugar in your diet.

Lisa Andrews, MEd, RD, LD

Source:

Materials provided by American Society for Nutrition. 

American Society for Nutrition. "Myth-busting study shows controversial seed oils reduce inflammation." ScienceDaily. ScienceDaily, 21 June 2025. <www.sciencedaily.com/releases/2025/06/250621103446.htm>.