Are Seed Oils Bad for You? A Simple Guide to Choosing Cooking Oils
Over the past few years, there’s been a huge rise in information shared online about seed oils, much of which seems at odds with mainstream health advice on their safety. In this article, I’ll look at the evidence from both sides and share some simple guidance on choosing oils for everyday cooking.
What are seed oils?
Seed oils are plant-based oils (also known as vegetable oils) which have been extracted from the seeds of various plants, for use in cooking.
Common sources include rapeseed (canola), soybean, sunflower, corn, safflower and grapeseed. The oil is extracted in two main ways; by mechanically pressing the seeds to squeeze out the oil or by solvent extraction. These two differing processes can have a dramatic effect on the quality, yield and in turn, the pricing of the oil.
Mechanically pressed extraction can either be cold (the traditional method which preserves more nutrients and flavour) or hot (the method of heating the seeds before pressing to increase the yield).
Solvent extraction involves using a food-grade solvent (usually hexane) to extract more oil from the seeds after pressing. The solvent is then removed, and the oil is refined, bleached and deodorised to produce a neutral-tasting oil with a longer shelf life.
Health Benefits
- Pressed oils tend to retain more of their natural compounds, with cold-pressed oils generally considered the least processed.
- Cold-pressed oils retain more of their natural compounds, including vitamin E and beneficial fatty acids such as omega-3 and omega-6.
- Refined oils can lose some of their natural compounds during processing, but they still provide fats that are an important part of the diet.
Seed Oils and Ultra Processed Foods
- If you regularly check ingredient labels, you’ve probably noticed that seed oils, especially rapeseed oil, show up in nearly all processed and ultra-processed foods.
- They’re in everything from salad dressings and sauces to bakery items and snacks.
- Manufacturers like to add seed oils to their foods for a number of reasons:
- Cost – Seed oils are relatively inexpensive to produce at scale, which makes them attractive for food manufacturers. They are often used in place of more expensive fats like butter or olive oil.
- Neutral taste – Seed oils are typically refined, bleached and deodorised (RBD), which removes strong flavours and creates a neutral oil with a higher smoke point.
- Shelf life – In some cases, oils may also be hydrogenated to improve stability and shelf life.
- Texture – Seed oils are widely used in food processing to enhance texture—helping keep bread soft, giving sauces a smooth, creamy consistency, and adding crispiness to fried foods.
What do health professionals say?
The UK’s official dietary guidance, including the Eatwell Guide, recommends choosing unsaturated fats over saturated fats. These include oils such as vegetable, rapeseed, sunflower and olive oil.
These fats are generally considered better for heart health when used in place of saturated fats like butter or lard.
That said, all fats, whether saturated or unsaturated, are high in energy, so it’s still recommended to use them in moderation as part of a balanced diet.
Which oils should you use?
When it comes to everyday cooking, there isn’t a one-size-fits-all answer. Both olive oil and rapeseed oil can be good options, depending on how you’re using them and your budget.
Extra virgin olive oil is a great choice for salads and lower-heat cooking, thanks to its flavour and higher levels of natural antioxidants.
Cold-pressed rapeseed oil is often more affordable and has a higher smoke point, making it a practical option for frying and everyday cooking.
As with most things, the overall quality of your diet matters more than any single ingredient, so choosing oils you’re comfortable using regularly is key.
Oil Comparison Table
| Oil/Fat | Best For | Smoke Point | Process | Cost | Notes |
|---|---|---|---|---|---|
| Extra Virgin Olive Oil | Salads, low heat | Medium | Cold-pressed | High | Flavour, antioxidants |
| Olive Oil | General cooking | Medium–High | Refined | Medium | Neutral taste |
| Cold-Pressed Rapeseed | Frying, roasting | High | Cold-pressed | Low | Budget-friendly |
| Sunflower Oil | Frying, baking | High | Refined | Low | Very common |
| Butter | Baking, flavour | Low–Medium | Minimal | Medium | Can burn |
| Ghee | High heat | High | Minimal | Medium–High | More stable than butter |
| Beef Tallow | Frying, roasting | High | Minimal | Medium | Traditional cooking fat |
| Goose Fat | Roasting | High | Minimal | High | Great for roast potatoes |
What I use at home
When it comes to cooking at home, I tend to keep things simple and stick to a small range of fats. I mainly use olive oil (including extra virgin), along with butter, goose fat or beef tallow depending on the dish.
That said, most health guidelines still consider seed oils safe to use, particularly in place of saturated fats. For me, the bigger focus is on cooking from scratch and limiting ultra-processed foods overall, rather than worrying too much about a single ingredient.