The shelf of the cooking-oil section of supermarkets has recently become a crowded spot, with an abundance of options to choose from. But this means it can be tricky to know which is the healthiest one, starting from the healthful olive oil to the more controversial palm and grapeseed oils.

Credit: Wikipedia Commons

To help select some of the healthiest, here’s a rundown of the most used ones across the world. Some oils have been well studied for their health benefits, while others have too little research from which to draw firm conclusions about their effects on heart health.

Since there are so many cooking oils across the world, it would be impossible to look at all of them, so we will only look at some of the most popular ones, seeing which are healthy and which not.

Olive oil

Used for cooking but also for soaps and fuel, olive oil is a vegetable oil obtained from the fruit of the Olive tree, a traditional tree crop of the Mediterranean Basin. It is regarded as a healthful dietary oil because of its high content of monounsaturated fat and polyphenols.

Buying the right kind of olive oil is very important. Extra virgin olive oil retains some of the antioxidants and bioactive compounds from olives. For this reason, it’s considered healthier than the more refined variety of olive oil. Even so, there is a lot of fraud on the olive oil market.

About 14% of the oil is saturated fat, whereas 11% is polyunsaturated, such as omega-6 and omega-3 fatty acids.  But the predominant fatty acid in olive oil is a monounsaturated fat called oleic acid, making up 73% of the total oil content. Studies suggest that oleic acid reduces inflammation and may even have beneficial effects on genes linked to cancer.

Apart from its beneficial fatty acids, it contains modest amounts of vitamins E and K. But olive oil is also loaded with powerful antioxidants. These antioxidants are biologically active and may reduce the risk of chronic diseases. They also fight inflammation and help protect blood cholesterol from oxidation — two benefits that may lower your risk of heart disease.

Extra-virgin olive oil can reduce inflammation, which may be one of the main reasons for its health benefits. The main anti-inflammatory effects are mediated by the antioxidants. Key among them is oleocanthal, which has been shown to work similarly to ibuprofen, an anti-inflammatory drug. Olive oil has also been found to be slightly better for the liver, in a recent study.

Sunflower oil 

Sunflower oil is a non-volatile oil that can be easily extracted from sunflowers. Although most people are already familiar with sunflowers, they don’t immediately think of sunflowers as sources of extremely healthy vegetable oil that can replace some of the less healthy cooking oils available on the market.

Sunflower oil is rich in vitamin E, vitamin K, phytosterols, and monosaturated fatty acids. One of the primary reasons for its growing popularity is its impressive fatty acid content, which includes palmitic acid, stearic acid, oleic acid, lecithin, carotenoids, selenium, and linoleic acid. The combination of fatty acids in the body is extremely important to maintain various elements of human health.

At the same time, some of those fatty acids, as well as vitamin E and other organic compounds, act as antioxidants in sunflower oil, which means that they can positively affect a huge range of conditions that people regularly suffer from. It also has more polyunsaturated fats than any other commonly used vegetable oil.

Three common grades of sunflower oil are available, and each varies in its nutritional content. High-oleic oil is from sunflowers bred to have a high concentration of oleic acid in their seeds. Mid-oleic is the oil that’s used for stir-frying and in salad dressings, while linoleic is formed by more polyunsaturated omega-6 fats but is lacking in healthy omega-3s.

Coconut oil

Unlike other plant-based oils, coconut oil is primarily 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.

Made from the fruit of the coconut palm tree, coconut oil has been promoted as a better alternative to butter. Nevertheless, there’s little scientific evidence of that. It is a white solid at room temperature with a consistency resembling that of butter or shortening rather than liquid oil.

Interestingly, however, a study comparing the use of coconut oil vs sunflower oil found no difference in the lipid-related cardiovascular risk factors between the two oils.

Palm oil

Palm oil comes from the fleshy fruit of oil palms. The main source of palm oil is the Elaeis guineensis tree, which is native to West and Southwest Africa. Its use in this region dates back more than 5,000 years. In recent years, oil palm growth has expanded to Southeast Asia, including Malaysia and Indonesia.

Palm oil is one of the least expensive and most popular oils worldwide, accounting for one-third of global plant oil production. It is an excellent source of tocotrienols, a form of vitamin E with strong antioxidant properties that may support brain health. It also has been linked to protection against heart disease, but with mixed results so far. Furthermore, although it is high in saturated fats, a Harvard study found that “Palm oil has been scientifically shown to protect the heart and blood vessels from plaques and ischemic injuries” and that “Palm oil consumed as a dietary fat as a part of a healthy balanced diet does not have incremental risk for cardiovascular disease.” 

However, while palm oil doesn’t really deserve all the negative reputation it gets (here’s why), it shouldn’t really be your first choice against other vegetable oils that are liquid at room temperature. Furthermore, because it is so cheap and robust, palm oil is used extensively in many processed foods, which should absolutely be avoided. The “healthy balanced diet” part in the above-mentioned study is a crucial aspect.

Furthermore, there are also several ethical issues regarding palm oil production’s effects on the environment, wildlife and communities. The increase in production due to the growing demand has led to the destruction of tropical forests and peatland in Malaysia, Indonesia, and Thailand. A recent study has also likened the palm oil industry lobby to that of the alcohol and tobacco industry due to its negative impact

Grapeseed oil

Grapeseed oil comes from the pressed seeds of grapes, making it a by-product of wine manufacturing. The health claims around it are based on its supposedly high amounts of nutrients, antioxidants, and polyunsaturated fats.

It’s very high in polyunsaturated fats, mainly omega-6. Scientists have speculated that a high intake of omega-6 fats, relative to omega-3s, may increase inflammation in the body. It also contains a significant amount of Vitamin E. However, calorie for calorie, it is not an impressive source of Vitamin E.

Very few studies have investigated the effects of grapeseed oil on human health. It is usually advertised as a good choice for high-heat cooking like frying. However, this may be bad advice, as grapeseed oil is also high in polyunsaturated fatty acids. These fats tend to react with oxygen at high heat, forming harmful compounds.

Canola oil

Canola oil is derived from rapeseed, a flowering plant, and contains a good amount of monounsaturated fats and a decent amount of polyunsaturated fats. Of all vegetable oils, canola oil tends to have the least amount of saturated fats. It has a high smoke point, which means it can be helpful for high-heat cooking.

That being said, in the United States, canola oil tends to be highly processed, which means fewer nutrients overall. “Cold-pressed” or unprocessed canola oil is available, but it can be difficult to find. It is a versatile and practical cooking oil that’s not very expensive and can be used in a variety of ways.

Avocado oil

More expensive than other oils and harder to find, avocado oil has a mild flavor similar to avocado, and the oil can withstand high cooking temperatures, making it suitable for sautéing, grilling, roasting or using in salad dressings.

It is rich in monounsaturated fat and it has one of the highest levels of monounsaturated fat among cooking oils, second only to olive oil. Like olive oil, avocado oil is also low in polyunsaturated fats. Compared with other vegetable oils, avocado oil has a higher saturated fat content (20 percent), but this percentage is much smaller than the percentage of saturated fat in butter.

So, which should I use?

Sadly, this is not a straight forward answer. Each of the cooking oils has different characteristics, which will help decide which one to buy based on what and how you are cooking.

Overall, it is safe to say that olive and sunflower oil have science-proven benefits and perform somewhat better healthwise than most alternatives — but both have shortcomings. That can also apply to canola oil, but only the unprocessed one. Meanwhile, doubts remain regarding grapeseed, avocado and palm oils, with further research needed.

It’s important to note that the cooking method can also drastically influence the behavior of oils. Olive oil seems to be best-suited for uncooked foods (such as salads), closely followed by sunflower oil. Oils with high smoke points may be more stable than those with low smoke points, and one study found that again olive oil is possibly one of the most stable ones. However, olive oil does lose some of its edge when cooked at high temperatures.

At any rate, cooking oil should only be consumed in moderation and as part of a healthy and balanced diet, low in processed foods. Avoid deep frying whenever possible. Bon appétit!