Are Seed Oils Healthy? A Nutrition Scientist’s Take
By Dr. Connie Weaver
Seed oils have become a frequent topic of debate in recent months. Headlines and social media posts often question how these oils are made, whether they contain harmful compounds and if they belong in a healthy diet at all. As a nutrition scientist, I think it’s important to move beyond the noise and look carefully at what the science tells us.
What Seed Oils Are and Why We Use Them
Seed oils – sometimes referred to as vegetable oils – are extracted from the seeds of plants such as soybeans, corn, sunflower and canola, which is derived from rapeseeds. These oils serve important functions in both home cooking and food production. They allow foods to be cooked at temperatures higher than boiling water, making them useful for frying and sautéing. They also contribute to texture, flavor and energy in many foods.
How Seed Oils Are Processed
A common concern is how seed oils are processed. Like many foods, oils undergo steps designed to improve quality, safety and stability. Seeds are ground to release the oil, which is then refined to remove unwanted flavors, colors and compounds. Processing steps remove components that can cause oils to spoil faster, separate improperly or develop unpleasant odors.
These steps are necessary because they extend shelf life, increase an oil’s smoke point (the temperature at which an oil begins to burn and produce visible smoke) and make it safer and more palatable for cooking. Without this processing, oils would spoil more quickly, contributing to food waste – an issue that already affects more than 30% of the U.S. food supply.
Addressing Concerns About Safety and Toxins
Another question I often hear is whether seed oils contain toxic compounds. Any naturally occurring toxins are removed during processing. It’s also important to remember that any fat, whether from plants or animals, can form harmful compounds if it becomes oxidized or rancid.
When seed oils are properly processed, stored and used as intended, they do not pose a toxicity risk.
Omega-6 Fatty Acids and Linoleic Acid
Much of the recent criticism of seed oils centers on linoleic acid, an omega-6 fatty acid found in many plant-based oils. Linoleic acid is an essential nutrient, meaning our bodies cannot produce it and must obtain it from food. While balance between omega-6 and omega-3 fatty acids is important, current scientific consensus does not support claims that omega-6 fats are harmful when consumed as part of a balanced, nutrient-rich diet.
In fact, a growing body of research emphasizes the importance of consuming adequate amounts of both omega-6 and omega-3 fatty acids. A 2024 paper published in the British Journal of Nutrition found that higher intake of omega-6 fatty acids is associated with a lower risk of cardiovascular disease.
How Seed Oils Compare to Animal Fats
Comparisons between seed oils and animal fats such as lard or beef tallow also benefit from context. Animal fats tend to be higher in saturated fatty acids, which the Dietary Guidelines for Americans recommend limiting to less than 10 percent of daily calories. Seed oils, by contrast, contain more unsaturated fats, including polyunsaturated fats that support heart health.
This is why nutrition guidance for decades has encouraged a shift from primarily animal-based fats – common in my mother’s generation – to plant-based oils.
The Role of Seed Oils in a Healthy Diet
So, can seed oils be part of a healthy diet? Absolutely. Much of the criticism directed at seed oils is really criticism of highly processed foods that are high in fats, sugars and salt. In those cases, the issue is the overall formulation of the product – not the oil itself.
When used appropriately, seed oils provide essential nutrients and help make food safe, stable and enjoyable. Choosing the right oil for the right purpose – such as considering smoke point and intended use – is a practical approach. Olive oil has received significant attention because Mediterranean-style diets that feature olive oil are associated with reduced risk of chronic disease, but seed oils such as soybean, corn and canola also play an important role in cooking and food preparation.
Putting Seed Oils in Perspective
When we look at the full body of evidence, seed oils are safe, nutritious and supported by sound science. Like all fats, they should be consumed in moderation and as part of an overall balanced eating pattern.
About Dr. Weaver
Dr. Connie Weaver is a Distinguished Research Professor of Nutrition Science at San Diego State University, California, Distinguished Professor Emerita at Purdue University, and CEO of Weaver and Associates Consulting, LLC. Dr. Weaver earned her Bachelor's and Master's of Science in Nutrition at Oregon State University and her doctorate in Nutrition from the University of Florida. She is an expert in nutrition science with a focus on women's health, botanicals and age-related diseases.