Mineral oils are the product of refining crude oil, removing contaminants, unwanted hydrocarbons and other natural substances. The first motor oils to be developed, they’re designed to be used on older, less advanced vehicle models, and as a result are lower-performance compared to newer, synthetic oils. Nevertheless, they are some of the cheapest lubricants available, and in the case of vintage and classic vehicles, are usually recommended by manufacturers.
It’s important to make sure your engine oils are properly topped up and in good condition, and this means regularly checking your motor oil level and changing it when needed. Doing so is easy:
Differences between synthetic and mineral oils
Then there’s the SAE standard (scroll up to ‘What is the viscosity grade of a motor oil?’ for more on that) and the API standard, which consists of two letters – the first meaning either S for petrol or C for diesel engines, and the second noting its overall performance, with letters towards the end of the alphabet indicating better performance.
There are two types of viscosity grade: multigrade and monograde:
You’ll then receive lubricants recommended by our expert engineers for use with your car or other vehicle.
Still, vegetable oils are refined and processed, which means they not only lack flavor, but also nutrients, Howard says. “Vegetable oil is guaranteed to be highly processed. It’s called ‘vegetable’ so that the manufacturers can substitute whatever commodity oil they want—soy, corn, cottonseed, canola—without having to print a new label,” she says. “Processed oils have been pushed past their heat tolerance and have become rancid in the processing.” Some of these oils, especially palm, are associated with more degradation of land for production, Howard says.
Avocado oil is a great choice. It’s unrefined like extra virgin olive oil, but it has a higher smoking point, which means it can be used to cook at higher heat and is great for stir-frys. It doesn’t have much flavor, which makes it a good option for cooking. “It’s just creamy, like an avocado,” says Howard. Avocado oil contains both monounsaturated and polyunsaturated fatty acids (it has one of the highest monounsaturated fat contents among cooking oils) as well as vitamin E. One downside is that it tends to be more expensive.
Depending on who you ask, coconut oil should either be avoided or embraced in moderation. The main point of conflict is its high saturated fat content; unlike other plant-based oils, coconut oil is primarily a saturated fat. Not everyone agrees that such a concentrated source of saturated fat is a no-go for health, but some experts, including the American Heart Association, argue that replacing foods that are high in saturated fat with healthier options can lower blood cholesterol levels and improve lipid profiles. Still, science is starting to suggest that not all saturated fats are bad for you.
That doesn’t mean it should be banned from the pantry. Saturated fats can be a healthier oil to use when you’re cooking at a very high temperature or frying food (something that definitely should be done in moderation), because they are more stable at high heat. This means that they are less likely to break down and smoke.
It’s also one of the healthiest oils to use when baking. “As a dressing it’s great, too,” says Howard. “And I like to put it into my lattes.”
Nut oils, like peanut, can be fun to experiment with in the kitchen, especially since there are so many different types. Peanut oil has one of the highest monounsaturated fat contents among cooking oils. It’s usually flavorful with a nutty taste and smell, and cooks well at high heat.
If you’re wondering which is the best cooking oil for your health—and which oils are not healthy—there’s some disagreement. TIME spoke to two cooking oil experts—Liz Weinandy, a registered dietitian at The Ohio State University Wexner Medical Center, and Lisa Howard, author of The Big Book of Healthy Cooking Oils—about how to choose the best option.
Polyunsaturated fatty acids, or PUFAs, include omega-3s and omega-6s. PUFAs can reduce cholesterol and triglycerides in the blood, especially when substituted for less-healthy fats.
Sunflowers are one of the few crops native to the United States. According to some sources, indigenous people likely began to cultivate them around 1000 BC. Sunflower seeds probably didn’t reach Europe until the 1800s. When sunflower seeds arrived in Russia, their oil content interested farmers. The farmers selectively bred the plants until they almost doubled the oil content of the seeds.
Sunflower oil is also a good source of these vitamins:
One tablespoon of sunflower oil contains: