Good for health, cooking… Or not? There are many preconceived ideas about vegetable oils. Let’s take stock, with Dr. Catherine Shanahan, author of the book Dark calories.
Misconception #1: Vegetable oils are good for your health.
Vegetable oils contain 99% lipids and their nutritional profile varies depending on their fatty acid composition (saturated, monounsaturated, polyunsaturated). If a consensus emerges to recommend virgin olive oil, it cannot represent the only source of fats because it is unbalanced in polyunsaturated fatty acids.
In The best way to eatthe authors recommend combining it with rapeseed oil for seasoning. Sunflower, corn and grapeseed oils have very poor omega-6/omega-3 ratios, for example 120/1 for sunflower oil. These oils excessively rich in linoleic acid (omega-6) weigh down the balance on the omega-6 side and should not be consumed exclusively and regularly. An excess of omega-6 is associated with inflammatory phenomena. The good omega-6/omega-3 ratio is around 3/1.
Misconception #2: Olive oil should only be used raw.
Olive oil can be used for cooking but at moderate temperature. Its beneficial compounds are best preserved if not heated.
Another misconception (conversely) is that olive oil is best for cooking, which is not entirely true as extra virgin olive oil has a relatively low smoke point (around 190°C), making it less suitable for high temperature frying than other oils. Most oils do not tolerate heat well. The strongest oils are tropical oils like virgin coconut oil.
However, high temperature cooking and frying are not cooking methods that we recommend. It is better to use gentle cooking at low temperatures (less than 100°C). In the oven, the temperature can remain reasonable by extending the cooking time.
Catherine Shanahan recommends this oil daily: “I use olive oil for dishes with a strong flavor: homemade pasta sauces, Italian, Mediterranean or Mexican recipes,” she says. Versatile, it is also used to roast vegetables, prepare vinaigrettes, marinades and mayonnaises. You can opt for unrefined olive oil, also known as extra virgin olive oil (EVOO), or, better yet, look for higher quality, unfiltered, unrefined olive oil. These types of oils are obtained by first cold pressing, without a refining step which would impoverish their nutritional value. »
The smoke point
The smoke point of an oil is the temperature at which it begins to break down and produce visible smoke when heated. This is a sign that the oil is degrading. Beyond this point, the oil loses its nutritional properties and can produce potentially harmful compounds. Extra virgin olive oil has a low smoke point, while other oils have a higher smoke point, such as peanut, refined sunflower, or coconut oil.
Misconception #3: Vegetable oils do not contain saturated fats.
We often think that saturated fats only come from animal products, this is false! Several vegetable oils (coconut, palm, palm kernel) contain high levels of saturated fats. In addition, palm oil generally gets a bad rap because of the environmental issues it poses (deforestation). But tropical vegetable oils (coconut, palm, palm kernel) can be interesting for cooking at high temperatures because their saturated fatty acids make them more stable than unsaturated oils. “Burning polyunsaturated fatty acids generates harmful free radicals much more quickly than burning saturated or monounsaturated fats”specifies Catherine Shanahan.
Misconception #4: Vegetable oils do not expire.
It is sometimes thought that oils can be stored indefinitely, when in reality oils, especially those rich in polyunsaturated fatty acids, can go rancid over time, especially if exposed to light, heat or air. Store your bottles of oils away from light and heat. Rapeseed oil should instead be kept in the refrigerator to limit oxidation phenomena. “Polyunsaturated fats are the least stable because they are likely to react with oxygen, a process called oxidation.”explains Catherine Shanahan.
