Cooking Oils: What You Should Know

Supermarkets are brimming with a wide array of oils—from economical sunflower and vegetable oils to more expensive options like olive and avocado oils, each claiming various health benefits.

There’s a long-standing debate surrounding oils and fats, and it really helps to understand the different types of fats present in them. Not all fats function the same way in the body—some can elevate cholesterol levels, while others may lower it.

Cholesterol, a natural fatty substance produced by the liver, is also present in some foods. An overabundance of bad cholesterol can lead to fatty deposits forming within blood vessel walls, making them narrower or even blocked.

Navigating the endless options can often feel a bit overwhelming, especially with all the conflicting messages out there.

Nita Forouhi, a Professor of Population Health and Nutrition at the University of Cambridge, shares insights on the BBC’s Sliced Bread podcast about oils. She notes that no single oil is a cure-all for health and aims to clear up three common misconceptions regarding cooking oils.

1. Sunflower and Vegetable Oil for Cooking

Rapeseed oil, which is often labeled as vegetable oil, along with sunflower oil, has received criticism for being overly processed and potentially causing inflammation that could harm cardiovascular health.

However, there’s no substantial evidence supporting these concerns. In fact, these oils have a low content—about 5-10%—of unhealthy saturated fats and are rich in healthier mono- and polyunsaturated fats. Essential polyunsaturated fats, like omega-3 and omega-6, are vital for both brain and heart health.

According to Forouhi, these oils are “definitely beneficial for us.” She emphasizes that they can help reduce disease risk when replacing saturated fats such as butter, lard, or ghee.

Costing around £2 per liter, they also offer a budget-friendly cooking option.

2. Margarine Can Lower Bad Cholesterol

Margarine has often been viewed with skepticism, with many choosing to avoid it. This stems from its history of containing harmful trans fats, which are linked to heart disease. However, Forouhi states that modern margarines now contain almost negligible amounts of trans fats. “So it can actually fit into a healthy eating plan and help lower bad cholesterol,” she says.

Butter isn’t entirely off the table either. “If you enjoy butter on your toast, go ahead and have it,” Forouhi suggests. While both margarine and butter can be used in cooking, she advises occasionally swapping them out for oils, which contain less saturated fat.

The UK health guidelines recommend keeping saturated fat intake under 10% of total calories, which is easier when cooking with oils instead of butter.

3. Olive Oil Not Suitable for Deep Frying

Different oils react uniquely when heated, making some unsuitable for frying. For instance, extra virgin olive oil has high levels of antioxidants and beneficial compounds, but its low smoke point means it’s better suited for drizzling on salads or dishes rather than for deep-frying.

The smoke point is the temperature at which fats start to decompose, potentially releasing unpleasant-tasting compounds. Restaurateur Tim Hayward notes that he uses a basic olive oil for shallow frying, but prefers sunflower or vegetable oil for deep frying foods like chips or battered fish, as they can handle higher temperatures without breaking down.

Some research suggests that oils heated beyond their smoke point can release toxic by-products. Yet, Forouhi points out that this kind of high-temperature cooking isn’t common in home kitchens, and long-term studies suggest vegetable oils are consistently associated with better health outcomes for chronic diseases.

Which Oils Should I Be Using?

If you’re looking for a straightforward strategy in the kitchen, consider the following:

• For everyday cooking: Sunflower or rapeseed oil are economical, healthy, and versatile. A standard olive oil could also work.

• For salads and finishing touches: Extra virgin olive oil adds both flavor and health benefits.

• For deep frying: Opt for oils with higher smoke points, like vegetable or sunflower oil.

• For flavor variety: Oils like sesame, coconut, or avocado can be used in cold dishes, even though they may not provide the same health benefits as olive oil.

In the end, it’s essential to focus on your overall diet rather than fixating on which oil to choose. Forouhi suggests going with what tastes good and fits your budget, while also experimenting with different oils to enjoy potential health benefits.