For decades, seed oils like sunflower, canola, soybean, and corn oil have been kitchen staples, widely used for cooking and food production. But recently, they have become the center of heated debates. Some public figures and online influencers claim these oils are dangerous, unnatural, and even toxic. US presidential candidate Robert F. Kennedy Jr. has been one of the loudest voices against seed oils, arguing that they are “poisoning” the public. His comments have sparked viral discussions and have even influenced some fast-food chains to switch to beef tallow. But is the fear justified? Many nutrition experts say these claims lack scientific backing and are based on misunderstandings.
How Are Seed Oils Made?
Seed oils have been commonly used since the 1950s. They include rapeseed (canola), sunflower, soybean, corn, sesame, and safflower oils. Most of these are made using a process called solvent extraction, which involves the use of hexane—a chemical solvent that removes oil from seeds. Critics argue that this makes the oils “unnatural” and harmful, but food scientists disagree.
Tom Sanders, emeritus professor at King’s College London, explains that refining removes unwanted substances, making the oils safe to consume. The European Union allows only tiny traces of hexane (1 mg per kg) in the final product, ensuring its safety. Sarah Berry, a professor of nutritional sciences at King’s College London, also confirms that refined seed oils are safe and contain no harmful residues.
The Omega-6 and Inflammation Debate
One of the biggest arguments against seed oils is that they contain omega-6 fatty acids, particularly linoleic acid, which some claim causes inflammation. The theory suggests that excessive omega-6 disrupts the balance between omega-6 and omega-3 fatty acids, increasing the risk of chronic diseases. However, experts say this idea is misleading.
Sarah Berry points out that while studies on mice have suggested omega-6 may have inflammatory effects, human studies do not support this conclusion. In fact, research shows that linoleic acid has either neutral or even anti-inflammatory effects in humans. Sanders calls the idea that omega-6 is toxic “nonsense,” noting that linoleic acid is an essential nutrient that the body needs. A deficiency can harm immune function and blood clotting.
Additionally, seed oils have been shown to support heart health. A 33-year study involving 200,000 people, published in JAMA Internal Medicine, found that replacing just one tablespoon of butter with a seed oil like soybean or canola daily reduced the risk of death by 17%. The study linked seed oil consumption to lower rates of heart disease and cancer. Sanders believes that the widespread adoption of seed oils has helped reduce cardiovascular disease rates over the past 50 years.
The Bigger Picture: Processed Foods and Health Risks
Some critics argue that seed oil consumption has increased alongside rising obesity and chronic illnesses, suggesting a direct link. But Berry stresses that “association does not mean causation.” She explains that around 60% of seed oils consumed today come from ultra-processed foods, which contain many other unhealthy ingredients. The real issue, she says, is the overall quality of processed foods, not the seed oils themselves.
A key example of this misunderstanding comes from a study in the 1960s. Researchers found that men with heart disease consumed more seed oils. However, the seed oils came from margarine that contained trans fats—now known to be harmful. This historical mistake has led some people to wrongly blame seed oils for modern health problems.
The Impact of Social Media and Misinformation
Despite strong scientific evidence supporting seed oils, many experts who speak out in favor of them have faced backlash. Berry, for example, received hate mail and online harassment after defending seed oils on a podcast. Some even called her “the most hated scientist in America.” The intense reaction almost made her stop discussing the topic. However, she ultimately decided that staying silent would only allow misinformation to spread further.
“They want to silence the science,” Berry says. “That made me more determined to keep going.”
Sanders believes that much of the fear surrounding seed oils is fueled by viral internet trends rather than solid scientific evidence. “This panic is just gossip,” he says. “The science is clear: seed oils are safe when consumed as part of a balanced diet.”
Should You Avoid Seed Oils?
Experts agree that there is no reason to fear seed oils. They provide essential nutrients, promote heart health, and have been a major factor in reducing cardiovascular disease rates. However, like any ingredient, they should be consumed in moderation as part of a balanced diet.
Scare stories and dramatic headlines tend to spread faster than scientific facts. As Berry puts it, “Clickbait wins over boring truth.” But the truth remains clear—seed oils are not harmful when used appropriately, and there is no scientific reason to avoid them.