You have probably heard that vegetable oils are better and healthier alternatives than butter or coconut oils because they are rich in saturated fat sources. Is this true?
First, let’s look at what vegetable oil actually is. It’s a triglyceride that is extracted from a plant and the oil is extracted mainly from seeds, but also from nuts, cereal grains and fruits too. The most commonly used vegetable oils include corn, soy bean, sunflower, peanut and canola (rapeseed) oil.
Many vegetable oils stay liquid at room temperature, but some stay solid and are therefore used as a substitute for butter. They are relatively cheap and easy to find, whenever you eat at a restaurant or you buy packaged food you are most likely consuming vegetable oil.
According to the American Health Association vegetable oils are heart healthy, and they list canola, corn, olive, peanut, safflower, soybean and sunflower oils in this category. However, vegetable oils are rich in polyunsaturated fat (PUFA) which are characterized by two or more double bonds which makes them prone to oxidation. Specifically, they are unstable during the storage and cooking process so they easily become oxidized, and this in turn can produce toxic byproducts. To improve the oxidative stability, and also actually to improve the flavor, these oils are often partially hydrogenated which in turn can reduce the content of the highly unsaturated linolenic acid.
Linoleic acid is a polyunsaturated fatty acid that is used by the body to make other types of omega-6 fatty acids. Omega-6s are essential to some extent, but most Americans consume too much of them, which can trigger chronic inflammation and other health issues. The biggest sources of linoleic acid in our diet tend to be processed foods. Around 75% of the fatty acid content in safflower oil comes from linoleic acid, and around 55% to 60% for corn and soybean oil.
According to a Harvard School of Public Health study, removing saturated fat and carbohydrates that are high in linolenic acid — the main source of which is vegetable oils — from the diet could lower the risk of coronary heart diseases and reduce total and LDL cholesterol. However, at the same time they suggested lowering overall carbohydrate intake as well. But some other studies produced different results and actually showed that higher consumption of linolenic acid may have pro-inflammatory properties.
Good examples of whole food fat sources include eggs, meat, avocados, fatty fish, nuts, seeds, and olives. These contain the oils that our body needs in a complete package, together with all of the connected nutrients. Vegetable oils on the other hand are not natural and are ultra processed. Also, ironically, they are not really derived from vegetables!
For some individuals it could be still beneficial to swap saturated fat sources such as butter and lard to vegetable oils or monounsaturated fats such as olive oil. But I am especially concerned mostly about the vegetable oils that are found in ultra-processed foods, fast foods and packaged food. We are consuming much more than any recommended amounts.
I think most of us would agree that limiting fast foods and ultra-processed foods is a good idea for our health. Eating a whole foods diet, minimizing anything that is highly processed, and limiting outside eating is always a great strategy for improving our health.
References:
1 — https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/healthy-cooking-oils
2 — https://www.sciencedirect.com/topics/food-science/vegetable-oil
3 — https://www.sciencedirect.com/topics/neuroscience/vegetable-oil
5 — https://pubmed.ncbi.nlm.nih.gov/25161045/
6 — https://healthyeating.sfgate.com/foods-high-linoleic-acid-9573.html
7 — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5492028/
8 — https://www.aboutoliveoil.org/cooking-oil-and-oxidative-stability
9 — https://lpi.oregonstate.edu/mic/other-nutrients/essential-fatty-acids
10 — https://www.hsph.harvard.edu/nutritionsource/2015/04/13/ask-the-expert-concerns-about-canola-oil/
