Seed Oils Explained: What They Are, What They Aren’t, and What Actually Matters

Seed oils have become the villain of the week. Depending on who you follow, they’re either “toxic industrial sludge” or “totally fine, stop panicking.”

As usual, the truth is much less dramatic and much more useful.

This is your calm, Scrummy breakdown of seed oils — without the doom, drama, or biochemistry degree.

What are seed oils, exactly?

“Seed oils” usually refers to oils extracted from — you guessed it — seeds.

The common ones:

• Sunflower oil

• Rapeseed/canola oil

• Soybean oil

• Corn oil

• Grapeseed oil

• Cottonseed oil

Most supermarket cooking oils and most restaurant fryers use some version of these.

They’re high in polyunsaturated fats (PUFAs) — especially omega-6 — which is where most of the online shouting happens.

Why do people say seed oils are “bad”?

There are three main arguments:

1. “They cause inflammation.”

What the evidence actually shows:

Eating excessive omega-6 without enough omega-3 may tilt things towards inflammation…but normal dietary amounts from cooking oils are not a problem.

You are far more likely to be inflamed from:

• chronic stress

• lack of sleep

• too much ultra-processed food

• barely touching fruit or veg

• zero physical activity…than from cooking with rapeseed oil at home.

2. “They’re highly processed — therefore toxic.”

Yes, seed oils are industrially processed.

No, that doesn’t make them poison.

Lots of foods are processed: yogurt, oats, bread, olive oil, tinned tomatoes.

Processing isn’t the enemy — over-consumption is.

3. “They oxidise when heated, which is harmful.”

True: all oils break down when overheated.

But this is not unique to seed oils.

If you heat any oil until it smokes — olive, butter, coconut, beef fat — it becomes less healthy.

So… are seed oils unhealthy?

Here’s the Scrummy take:

Seed oils are fine in normal everyday use.

They are not a superfood.

They are not a poison.

They are just… oil.

Where problems can happen:

• Restaurant fryer oil used over and over

• Ultra-processed foods high in seed-oil calories and low in nutrients

• A diet with almost no omega-3s (oily fish, nuts, seeds)

The issue is not “seed oils.” The issue is context.

The part no one talks about: quantity

You could switch to avocado oil or coconut oil tomorrow……but if you’re still eating 80% of your calories from ultra-processed stuff, you’ll feel exactly the same.

The biggest driver of health is your overall pattern, not whether your sauté pan saw a sunflower.

So what should you actually do?

Here’s the Scrummy, no-nonsense approach:

1. Use whatever oil you like at home.

Rapeseed, olive, sunflower — pick the one that works for your cooking style and budget.

2. Don’t let any oil smoke.

If it’s smoking, it’s burning. New pan, lower heat, better day.

3. Eat omega-3s a few times a week.

Salmon, mackerel, sardines, walnuts, chia seeds.

4. Keep UPFs to a sensible minimum.

Fewer crisps, pastries, deep-fried takeaways = fewer oxidised oils.

5. Chill out.

Nutrition is not a crime scene.If you’re doing the basics well, seed oils are not going to make or break your health.

The bottom line

Seed oils are not the villain social media wants them to be.

They’re a perfectly fine part of a balanced, realistic diet — especially when you’re cooking at home, eating actual food, and not burning everything to a crisp.

In other words:

You don’t need to fear seed oils. You just need a bit of common sense.

And that’s exactly what Scrummy is for.