Seed Oils are a type of vegetable oil that is extracted from plants. Some common examples of seed oils are soybean oil, sunflower oil, cottonseed oil, sesame oil, rice bran oil, peanut oil etc. 1.
Seed oils consist of Polyunsaturated fatty acids (PUFA), which are Omega 3 and Omega 6 fatty acids to name a few. In earlier studies, polyunsaturated fatty acids were linked with reduced risks of heart problems but many scientists are now concerned with the amount of omega-6 fatty acids present in them. Omega-3 on the other hand is considered beneficial for health 1. It has been studied that if we take too much omega-6 compared to omega-3, we are more likely to suffer from chronic inflammation.
Chronic inflammation and oxidative stress in our body account for the risk of most diseases like heart diseases, atherosclerosis, diabetes, hypertension, arthritis, obesity and inflammatory bowel disease 1.
Another reason why polyunsaturated fatty acids are considered unhealthy is that the double bonds present in these types of fatty acids are more susceptible to oxidation. On heating at a high temperature, these oils get oxidised and unstable and tend to get rancid. The fatty acids react with the oxygen in the atmosphere and lead to the formation of free radicals and oxidative stress in our bodies. And as a result, chronic inflammation persists 1.
What is to be noted is that these fats along with getting stored for energy, also go to the cell membranes. Hence, the cell membranes also get sensitive to oxidative stress and inflammation when we consume excessive amounts of polyunsaturated fatty acids. In other words, these oxidised fats can be toxic and harmful to your body even at the cellular level 1.
Seed oils undergo many processing techniques at the manufacturing level, such as hydrogenation, and often form trans fats due to changes in their chemical structure. These trans fats are found in many processed foods, margarine, ice cream and cookies, etc. 1.
The double bonds in these polyunsaturated fatty acids of the seed oils are more chemically reactive and sensitive to heat. In comparison, saturated fats and monounsaturated fatty acids are a bit resistant to heating, and hence can be suggested for cooking 1.
Coconut oil is considered to be best in it's virgin forms, and not refined. Even Butter and Ghee are good as they contain low amounts of Polyunsaturated fats. 92% of coconut oil has saturated fats and only 1.6 % of Polyunsaturated Fatty Acids which makes it resistant to heating. Butter has just 4% of polyunsaturated fats only. These oils have more resistance to heat, and can raise the HDL or good cholesterol in our bodies.
It has always been controversial and debated the comparison between the use of saturated and unsaturated fats. The latest studies say that saturated fats when used in optimal quantities can be advised as they are resistant to heating and oxidation. The same is studied about monounsaturated fats. Seed oils have excessive amounts of omega-6 (a type of polyunsaturated fatty acid), undergo a lot of processing and get easily oxidised and cause inflammation 1.
In conclusion, coconut oil, butter, and ghee are the best forms of oils and soybean oil, sunflower oil, groundnut oil, sesame oil, rice bran oil, etc are seed oils that must be avoided due to their toxic compounds 1.
References :
- Are Vegetable and Seed Oils Bad for Your Health? Are Vegetable and Seed Oils Bad for You? A Critical Look
- What Is Saturated Fat and Is It Unhealthy? What Is Saturated Fat and Is It Unhealthy?
- When Vegetable Oil Isn’t as Healthy as You Think | Time When Vegetable Oil Isn't as Healthy As You Think
- 5 Healthy Cooking Oils (and 4 to Avoid) 5 Healthy Cooking Oils (and 4 to Avoid)