Let’s play a game. Name a food villain that wellness gurus love to blame for everything from obesity to chronic disease to inflammation and everything in between. If you guessed seed oils, bingo! You’ve won a free ticket to Pseudoscience Land, where fear-mongering sells and facts are an afterthought.
Seed oils—like rapeseed (that’s canola to you Yanks), sunflower, sesame and corn oil—have been demonised so hard you’d think they were the reason your ex left you on read. But here’s the truth: seed oils aren’t out to get you. They’re just oils. And the whole “toxic seed oil” melodrama? Mostly a con to flog you overpriced alternatives (looking at you, £15 avocado oil and carnivore diet plans).
What Even Are Seed Oils?
Seed oils are oils from any kind of seed; whether that be rapeseed, sesame seed, flaxseed or anything in between. They’re packed with polyunsaturated fats (PUFAs), including omega-6 fatty acids, which are essential fatty acids. Omega-6’s have been the bearer of the brunt of the misinformation and fear mongering about food and inflammation over the past few years; let’s talk about it.
The Origins of the Omega-6 Fear
1. The “Inflammation” Myth
The backlash started with early lab studies showing that omega-6s (like linoleic acid) can be converted into arachidonic acid, which produces inflammatory molecules in test tubes. Cue panic.
But here’s the catch:
- Human bodies tightly regulate this process—eating more omega-6s doesn’t mean more inflammation.
- Omega-6s also make ANTI-inflammatory compounds (like lipoxins).
- Real-world studies don’t support the inflammation scare (more on that below).
2. The Rise of Paleo & Carnivore Grifters
The anti-seed oil movement got turbocharged by fad diets (Paleo, Carnivore) and influencers who blamed modern foods for all health problems. Omega-6s became a convenient scapegoat because:
- They’re in processed foods (though that’s a food quality issue, not an oil issue).
- They’re more abundant now than in Stone Age diets (but so are antibiotics and Netflix—correlation ≠ causation).
3. Misinterpreted Animal Studies
Rats fed extremely high doses of omega-6s showed some negative effects. But:
- Humans aren’t giant lab rats.
- We eat omega-6s alongside omega-3s and other fats (unlike controlled experiments).
As Dr. Kevin Klatt, a nutrition researcher at UC Berkeley, puts it:
“The idea that seed oils are uniquely harmful is like saying tea is toxic because you could drown in it. Context matters.”
The Great Seed Oil Scare: Where Did It Come From?
The anti-seed oil hype is like a bad game of Chinese whispers. It started with some legit concerns about processed foods, got twisted into “all omega-6s are evil,” and now everyone seems to be concerned and downright fearful of even a drop of seed oils touching their lips.
But what does science say?
Almost all Meta-Analyses Says: Calm Down
A 2020 meta-analysis in Circulation looked at over 40 studies and found:
“Replacing saturated fats with polyunsaturated fats (like those in seed oils) was linked to a lower risk of heart disease.” (Source)
Another 2017 review in Nutrients concluded:
“There’s no evidence that omega-6 fatty acids cause inflammation in humans.” (Source)
But wait—what about the claim that seed oils are “highly processed” and therefore dodgy?
Processing ≠ Poison
Yes, seed oils are processed. So is your oat milk, your protein powder, and that organic kale crisp bag you paid £7 for. Processing isn’t inherently bad—it’s about the end product, how much you use of those products, and the nutrition within that product.
Just because something is processed or refined doesn’t mean it is toxic. Many foods are more nutritious because of processing; fortified plant milks add calcium and iodine and reduce risk of deficiency, cooking tomatoes increases the content of lycopene, boiling beans allows easier digestion and removes compounds which can be harmful.
As dietitian Abbey Sharp says:
*“Refined ≠ toxic. We refine salt, sugar, even water. The issue isn’t processing—it’s how much ultra-processed *crap* we eat, not the oils themselves.”*
The Omega-6/Omega-3 Ratio Scare (Debunked)
- Some claim we need a “perfect ratio” (like 1:1 or 4:1) of omega-6s to omega-3s.
- Reality: There’s no magic ratio—total intake matters more. Most Westerners just need more omega-3s (fish, flaxseeds, walnuts and chia), not less omega-6s.
The reality is, people who eat a diet high in fried foods, ultra-processed foods and foods which are generally unhealthy for us will consume omega-6 far in excess of omega-3. But is it this which is causing the problem? No. It’s likely the formation of trans-fats from keeping the oils at high temperatures for long times, and the over consumption of high calorie, low nutrient foods.
The Real Problem: Overdoing It (Like Everything Else)
Here’s the kicker: The issue isn’t seed oils—it’s that we eat too much fried food. Shocking, right? If you’re smashing kebabs and chips daily, yeah, your health might take a hit. But that’s not the oil’s fault—it’s the diet pattern.
Dr. Stephan Guyenet, neuroscientist and obesity researcher, nails it:
“Blaming seed oils for obesity is like blaming forks for making you fat. It’s not the utensil, it’s how you use it.”
Ultimately, there is no correlation between adverse health effects from seed oils when they are used within a generally healthy diet pattern; for example, using a seed oil to roast some potatoes or stir-fry some vegetables is not the same as eating deep fried foods, which is shown to have negative consequences. In fact, we generally see a net positive in many outcomes, including reduced inflammation and reduced risk for cardiovascular disease when we use seed oils in this way, especially if we are replacing lard, butter, ghee or tallow with them.
So Should You Bin Seed Oils?
No. Unless you’re deep-frying your meals in them morning, noon, and night, they’re fine. The reality is;
- They’re affordable and stable for cooking (rapeseed oil has a high smoke point).
- They provide essential fats your body can’t make.
- They can be a great alternative to saturated fats which have been shown to increase risk of inflammation and heart disease (you know, the things carnivore grifters are always trying to tell you are actually caused by rapeseeds)
Final Thought: Don’t Fall for the Con
The wellness industry thrives on scaremongering. First it was fat, then carbs, then gluten, now seed oils. The cycle repeats because dodgy claims sell supplements, books, and ‘clean eating’ guides.
So next time someone tells you seed oils are toxic, ask:
- “Where’s the human trial showing harm?” (Spoiler: There isn’t one.)
- “What are you selling?” (Probably a £40 “toxin-free” cookbook.)
Eat your greens, exercise more, sleep well, and cook with whatever bloody oil you fancy. Life’s too short to fear a bit of salad dressing.
TL;DR: Seed oils aren’t bad. The grift is. Now pass the roast potatoes (cooked in rapeseed oil, because I like to live dangerously).
References & Further Reading:
Diets Debunked 