You’ve seen seed oils, also sometimes called vegetable oils, in plastic containers at your supermarket. Examples are corn oil, canola oil, and soybean oil, which manufacturers love because they’re cheap to produce.

Besides being the most common oils people cook with, these oils are also in processed and packaged foods. Although there’s no direct proof that they directly cause health issues, there are reasons you should limit them in your diet. Let’s look at some of those.

Seed Oils May Cause Inflammation.

Inflammation is the body’s natural response to injury or infection. In a positive sense, inflammation protects your body against invaders by causing blood vessels to dilate. This allows white blood cells and other immune cells to reach the site of injury, so they can attack foreign elements that may be present.

Inflammation is a healthy response, but it can become harmful if it continues for an extended period.

Industrial seed oils are rich in omega-6 fatty acids (types of fat). Some research suggests that high levels of omega-6 fatty acids relative to omega-3s promote inflammation when consumed in large quantities.

Omega-6 fatty acids are in many processed foods, but they’re also in industrial seed oils like corn oil and sunflower oil. The oils also undergo extensive heat processing during extraction and refining processes, which increases their omega-6 content further and makes them more likely to trigger inflammation.

So, high if you’re feeling tired, ache all over, or have pain in your joints, the inflammatory properties of these oils could be a contributor. Therefore, it’s important to balance your intake of omega-3 (an anti-inflammatory fatty acid in fatty fish and some plant-based foods) and omega-6 fats.

You need both types of fatty acids in your diet, but too much omega-6 could lead to chronic inflammation and potentially contribute to heart disease, cancer, diabetes, and other health problems field by inflammation.

In modern society, people get roughly 20 times the amount of omega-6s relative to omega-3s, when a healthier balance would be more like 2 to 1.

Seed Oils May Be Rancid In The Bottle

Seed oils are highly processed and subjected to high heat. They’re extracted at high temperatures, which damages the fatty acids. Rancid fats have been linked to chronic inflammation and oxidative stress.

Rancidity is a process that occurs when oils encounter high heat, light, and oxygen, which can cause the oil to break down and develop an off smell and taste.

Industrial seed oils are usually refined, which removes their impurities and extends their shelf life. However, even refined oils can go rancid if you don’t store them properly or if they are past their expiration date.

Store all oils in a cool, dark place, and use them before their expiration date to ensure they are as fresh as possible. Also, don’t heat them to their smoking point.

Seed Oils Release Toxins if You Overheat Them

Some seed oils have a low smoke point and can release toxins when you overheat them. The smoke point of an oil is the temperature at which it begins to break down and release smoke. When an oil reaches its smoke point, it releases harmful compounds and has an off taste and smell.

Always use oils with a high smoke point, such as peanut oil or grapeseed oil, for high-heat cooking methods like frying. Even better, use lower temperature methods of preparing food and healthier oils, like olive oil with its monounsaturated fats, a heart-healthy type of fat.

Industrial Seed Oils Are Highly Processed

Industrial seed oils are processed in ways that reduce their health benefits and render them potentially harmful. You might be surprised at how highly processed they are:
• They’re extracted at high temperatures, which damages the fatty acids.
• They’re refined and bleached to remove color and flavor, resulting in a bland flavor, but also removing beneficial components of the oil.
• Deodorization is used to remove volatile compounds from seed oils, including many antioxidants.
• Hydrogenation involves adding hydrogen to an unsaturated fat (one with double bonds) molecule so that it becomes saturated (no double bonds). This creates an unhealthy trans-fat form of fat that increases cholesterol levels while lowering good HDL cholesterol by up to 15%. Trans fats are also linked with cardiovascular disease.

One way industrial seed oil manufacturers prevent oxidation during processing is by treating their products with solvents like hexane and, in some cases, industrial chemicals such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tertbutylhydroquinone (TBHQ).

These additives may help prevent damage from light exposure during storage or transportation. Although generally recognized as safe, there are concerns that these chemicals may cause cancer.


The takeaway from this article should be that the seed oils in our food supply aren’t healthy. They have been processed to make them seem more like traditional fats. If you want your food choices to support your health rather than harm it, avoid all forms of industrial seed oils–even those labeled “organic” and choose unprocessed oils, like extra-virgin olive oil and avocado oil.


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