
A new study has found that higher levels of linoleic acid—a type of omega-6 fatty acid found in seed oils and plant foods—are linked to better heart and metabolic health. The research adds to growing evidence that seed oils, such as soybean and corn oil, may actually reduce the risk of heart disease and type 2 diabetes, contrary to recent claims that these oils are harmful.
Linoleic acid is the most common omega-6 fat in the human diet. It’s found in vegetable oils, nuts, seeds, and other plant-based foods. In recent years, seed oils have come under scrutiny, with some people suggesting they cause inflammation and contribute to chronic disease. However, this new study challenges those claims with real biological data.
“Our research found that people with higher levels of linoleic acid in their blood had lower levels of risk markers for heart disease and type 2 diabetes,” said Dr. Kevin C. Maki, the study’s lead author and an adjunct professor at Indiana University School of Public Health–Bloomington.
Dr. Maki presented the findings at NUTRITION 2025, a major conference organized by the American Society for Nutrition in Orlando, Florida.
What makes this study especially strong is its use of blood biomarkers—chemical indicators found in the blood—to assess linoleic acid levels. Unlike studies that rely on self-reported food records, this approach gives a more accurate picture of how much linoleic acid people are actually absorbing from their diets.
The study analyzed data from 1,894 participants from a COVID-19 observational cohort. Researchers looked at the amount of linoleic acid in participants’ blood plasma and compared it with a wide range of health markers linked to heart and metabolic conditions. These included blood sugar levels, insulin, insulin resistance, and several key indicators of inflammation.
The results were consistent across the board:
People with more linoleic acid in their blood had lower levels of glucose and insulin, meaning better blood sugar control.
They had lower HOMA-IR scores, a marker that signals less insulin resistance.
They also had lower levels of inflammatory markers, including C-reactive protein (CRP), glycoprotein acetyls, and serum amyloid A—all of which are linked to increased risk of heart disease and metabolic disorders.
“These results suggest that linoleic acid is not only safe but may actually protect against the very diseases it’s sometimes blamed for,” said Dr. Maki.
This new research lines up with previous observational studies that found similar results—people who eat more linoleic acid tend to have lower risk of heart attacks, strokes, and type 2 diabetes. But the key difference here is that this study used objective measurements in the blood rather than relying on people to remember or report what they ate.
While the results are promising, the researchers note that this is still an observational study. It cannot prove that linoleic acid directly causes these improvements, only that there’s a strong link. Still, it lays the groundwork for future clinical trials that could test what happens when people increase their intake of linoleic acid through diet.
Next, the team plans to compare different types of oils and their fatty acid profiles to see how they affect blood sugar, inflammation, and other important health markers.
In summary, this study supports the idea that seed oils and other sources of linoleic acid may be beneficial for heart and metabolic health—offering a science-based counterpoint to concerns that these oils are harmful.
If you care about heart health, please read studies that yogurt may help lower the death risks in heart disease, and coconut sugar could help reduce artery stiffness.
For more information about health, please see recent studies that Vitamin D deficiency can increase heart disease risk, and results showing vitamin B6 linked to lower death risk in heart disease.
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