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Seed oils such as sunflower, canola, soybean, and corn oil have been part of our kitchens for decades. These oils are used in everything from frying to salad dressings, making them staple ingredients in many households. However, in recent years, they have come under intense scrutiny. Public figures, including U.S. presidential candidate Robert F. Kennedy Jr., have criticized these oils, calling them toxic, unnatural, and harmful. Kennedy, in particular, has stirred controversy by claiming that seed oils are “poisoning” the public and urging people to return to traditional fats like butter and lard.

His comments have sparked viral debates, even leading some fast-food chains to announce their decision to switch to beef tallow instead of seed oils. Despite the growing public panic, many nutrition experts argue that these claims are misleading and not backed by solid scientific evidence. So, what’s the truth about seed oils? Are they really as harmful as some claim, or have they become the target of unnecessary fear?

How Seed Oils Are Made and Why That Matters

Seed oils have been in use since the 1950s and are made from crops like rapeseed (canola), sunflower, soybean, corn, sesame, and safflower. Most of these oils are produced through a process called solvent extraction, which uses hexane, a chemical compound. However, the hexane is nearly entirely removed during refining, and the European Union allows only trace amounts (1mg/kg) to remain in the final product.

Critics of seed oils often point to the refining process, including steps like bleaching and deodorizing, as evidence that these oils are unnatural. However, many nutrition scientists disagree with this view. Tom Sanders, emeritus professor at King’s College London, explains that refining is actually a beneficial process because it removes harmful substances from the oil. Sarah Berry, a professor of nutritional sciences at King’s College and chief scientist at the nutrition company Zoe, echoes this sentiment, stating that the finished oils are “very safe to eat.”

Omega-6, Inflammation, and Misunderstood Science

A major argument put forward by critics of seed oils is that omega-6 fatty acids—especially linoleic acid—cause inflammation in the body. The theory is that an imbalance of omega-6 and omega-3 fatty acids could lead to inflammation, as both types of fatty acids use the same enzymes. However, nutrition experts argue that this theory is misleading when applied to human biology.

Berry explains that while this concept may hold true in mice and laboratory models, it does not apply to humans. Studies involving humans have shown that linoleic acid, the main omega-6 fatty acid in seed oils, either has no effect or even has anti-inflammatory properties. Sanders further debunks the idea that linoleic acid is harmful, calling it “nonsense” and stressing that it is an essential nutrient. A deficiency in linoleic acid can impair immune function and platelet activity, both of which are crucial for overall health.

In fact, linoleic acid has been shown to have benefits, such as lowering cholesterol levels and supporting heart health. A large, 33-year study involving 200,000 participants found that replacing just one tablespoon of butter with plant-based oils like soybean or rapeseed oil every day reduced the risk of death by 17%, including from heart disease and cancer. Sanders believes that the widespread adoption of seed oils has played a significant role in the decline of cardiovascular disease rates over the past 50 years.

Context Is Key: It’s Not Just About the Oil

Critics of seed oils often link their increased consumption to the rise of chronic diseases. However, experts like Berry caution that this view oversimplifies the issue. “Association does not mean causation,” she says. While seed oils have become more prevalent in the modern diet, especially in ultra-processed foods, the overall quality of the diet is what matters most. Today, approximately 60% of the seed oils consumed come from ultra-processed foods, which often contain other harmful ingredients, such as added sugars and artificial chemicals.

The problem, according to Berry, is not seed oils themselves but the overall impact of ultra-processed foods on health. These foods, which are often high in unhealthy fats, sugars, and salt, can contribute to chronic conditions like obesity and heart disease. Historical studies have also contributed to the confusion. For instance, a 1960s study found that men with heart disease consumed more seed oils, but these oils were typically found in margarine, which contained harmful trans fats. Today, we know that trans fats are dangerous, but seed oils in their pure, refined form do not pose the same risks.

A Scientist Under Fire: The Battle Against Misinformation

Despite presenting evidence-based arguments in defense of seed oils, Sarah Berry has faced a wave of online backlash. After defending seed oils on a podcast, she received hate mail and was even labeled “the most hated scientist in America.” At one point, she considered ceasing her public advocacy, but she ultimately chose to continue speaking out. “They want to silence the science,” she says. “That made me more determined to keep going.”

Berry and Sanders both emphasize that the panic surrounding seed oils is based on misinformation. Sanders dismisses the fear as “just gossip” without any solid scientific backing. Both experts agree that a healthy diet is about balance—not vilifying one specific ingredient. The real issue lies in the quality of the overall diet, not the presence of any one food or oil.

Unfortunately, fearmongering and dramatic headlines often capture more attention than calm, evidence-based explanations. As Berry notes, “Clickbait wins over boring truth.” Despite the loud voices spreading fear, the scientific consensus is clear: seed oils, when consumed as part of a balanced diet, are safe and even beneficial to your health.

The Bottom Line: Don’t Fear Seed Oils

The growing fear of seed oils, driven in part by influencers and high-profile critics like Robert F. Kennedy Jr., is largely based on misinformation. The oils themselves are not inherently harmful. When consumed in moderation and as part of a healthy, balanced diet, seed oils can be a safe and beneficial source of essential fatty acids, such as omega-6.

The real issue lies not in seed oils, but in the overall quality of the modern diet, which is increasingly dominated by ultra-processed foods. If you want to improve your health, focusing on whole, minimally processed foods and avoiding excessive consumption of refined oils, sugars, and unhealthy fats is a far more effective approach than demonizing any one ingredient.