Seed Oils

Separating Facts from Myths

My kitchen fave: Extra Virgin Olive Oil.

Seed oils — like sunflower, canola, soybean, and corn oil — have become a hot topic in the health world. You may have heard the narrative that seed oils are “bad” and a major culprit behind the rise in chronic metabolic diseases such as obesity, diabetes, and heart disease.

But is this really the full picture?

Let’s unpack the facts.

What the Signs Say — And What They Don’t

Some epidemiological studies have noted a correlation: as seed oil consumption has increased over the last several decades, so too have rates of chronic metabolic conditions. At first glance, this might seem like a smoking gun implicating seed oils as the villain. However, correlation is not causation.

As nutrition researcher Dr. Sarah Berry points out, this association has often been misinterpreted. Many of these studies don’t prove that seed oils cause disease; rather, they show that seed oils have risen in tandem with processed food consumption and other lifestyle factors that contribute to poor health outcomes.

New Insights from Recent Research

A recent large-scale study published in JAMA Internal Medicine by Yu Zhang et al. (2025) examined the impact of butter and plant-based oil intake on mortality risk. The study found that higher consumption of plant-based oils, including seed oils, was associated with lower mortality, whereas higher butter intake was linked to increased mortality risk. This adds further evidence supporting the safety and potential benefits of plant-based oils when used appropriately.

Seed Oils and Ultra-Processed Foods

One key factor is that seed oils are heavily used in ultra-processed foods (UPFs) — think packaged snacks, fast food, and convenience meals. UPFs contain many unhealthy ingredients: excessive sugar, refined carbs, additives, and unhealthy fats. The overall quality of these foods—not just the seed oils alone—drives much of the metabolic disease risk.

Omega-6 Concerns Are Overblown

Seed oils are rich in omega-6 fatty acids, which some claim are inflammatory and harmful in high amounts. However, current evidence shows that high omega-6 intake is generally fine as long as you maintain a good balance of omega-3 fatty acids in your diet. Good sources of omega-3s include fatty fish like salmon, mackerel, and sardines, as well as plant-based options like flaxseeds, chia seeds, walnuts, and hemp seeds. It’s this balance that supports healthy inflammation regulation and overall wellbeing.

So, Are Seed Oils Bad for You?

Not necessarily. Seed oils are not inherently harmful when used properly. In fact, many seed oils contain polyunsaturated fats (PUFAs) that can support heart health when they replace saturated fats or trans fats in the diet.

That said, seed oils don’t have the same potent health benefits as extra virgin olive oil, which is rich in antioxidants and monounsaturated fats linked to reduced inflammation and better cardiovascular outcomes.

What to Watch Out For

• Highly refined seed oils are often processed using high heat, pressure, and chemical solvents. This intense refining strips away natural antioxidants and nutrients, and can create harmful oxidation products and trace trans fats. Highly refined oils also tend to have a higher smoke point, making them popular for industrial food manufacturing and deep frying. However, these oils lack many of the health benefits found in cold-pressed or minimally processed oils.

• Repeatedly heated seed oils (like those used over and over in deep frying) can degrade further, producing harmful compounds. It’s best to avoid or limit consumption of fried foods from fast food outlets or restaurants that reuse oil excessively.

• For home cooking, choose cold-pressed or minimally processed seed oils when possible. Seed oils such as sunflower, canola, or safflower oil are generally safe when used at appropriate temperatures.

• And if in doubt, extra virgin olive oil is your safest and most healthful bet for cooking, baking, and dressings.

  
  

If in Doubt, Choose Extra Virgin Olive Oil

If you’re unsure which oil to use, my personal recommendation is to choose extra virgin olive oil (EVOO). I prefer the taste and have replaced most other oils and fats in my cooking and baking with olive oil. I even bake carrot cake with olive oil — and spread it on my bread instead of butter!

Give it a try; it tastes better than you might think.

The Bottom Line

Seed oils themselves are not toxic per se and not the dietary villains they’re sometimes made out to be. The real issue is often the context in which they are consumed — mostly in highly processed, nutrient-poor foods. By choosing whole, minimally processed foods and cooking mindfully at home, you can enjoy seed oils safely.

First choice for me remains the powerful and health-boosting extra virgin olive oil.

References: Berry, Sarah. “Are seed oils bad for health? Debunking myths and understanding the evidence.” Nutrition Today, 2023.

Zhang, Yu et al. “Butter and Plant-Based Oils Intake and Mortality.” JAMA Internal Medicine, March 6, 2025.