SEEd OILS? TOXIC MACHINE-LUBRICANT OR HEALTH FOOD?

There has been a lot of buzz the last few years over “industrialized vegetable seed oils”. Some influencers speak about them as if they are straight up poison. Others seem to think they should be in the drinking water. RFK has demonized them openly over his career. More recently, the fast food restaurant Steak and Shake has made a public commitment to replace their frying oil with beef tallow instead of seed oils. “Seed oils” or “vegetable oils” typically refers to oils from the seeds of certain plants, the “hateful eight” as they are so called, including canola, corn, cottonseed, grapeseed, soybean, sunflower, rice bran, and peanut. These oils are highly refined and are only possible due to modern science and technology. We traditionally did not have the means to extract oils from these seeds as they come in such low quantities and are bound up in a whole food matrix, making them difficult to isolate. The refining process typically requires being soaked in hexane, which acts as a solvent to extract the oils. The oils are then isolated from the hexane by heating the mixture to evaporate off the hexane. The heating process can be highly damaging to the oil, introducing unwanted smells, flavors, and colors which then require their flavors/smells/color neutralized in order to be palatable. They are put through a process of chemical deodorization and bleaching in order to achieve this. This calls into question the safety of the production of these oils, as the chemicals used to extract and deodorize them are often toxic to humans. Hexane in particular is classed as a neurotoxin. Are the oils becoming contaminated with these chemicals?

“Industrialized seed oils”, notably, does NOT refer to oils extracted using cold expeller pressing, which is a more natural alternative method that basically involves using a press machine to crush the seeds and then uses gravity and a form of filtration to isolate the oils. This has been done for thousands of years, most notably in the production of olive oil in the mediterranean regions or sesame oil in the middle east. Most olive oil, avocado oil, sesame oil, oils extracted from nuts such as macadamia, walnut, and almond, coconut oil and recently some forms of algae oil, are done in this way.  These oils are extracted in a less harmful way as they are not exposed to high heat or industrial chemicals, preserving the quality of the oil. The “industrial seed oils” listed in the opener can technically be produced using expeller pressing but their yield is much lower, making it not very cost effective. Some of them also tend to come out “gummy” meaning the oil is not being purely isolated. 

I mentioned these oils being fragile. In what way are they fragile? Oils, fats, fatty acids, are all interchangeable terms for a class of organic molecules called hydrocarbons. Hydrocarbons are named as such because they are primarily composed of hydrogen and carbon. Their structure consists of long strings of carbon atoms bonded together that act as a backbone of a chain with hydrogen atoms bonded to the carbons. They generally fall into 3 categories: saturated, monounsaturated (MUFA), and polyunsaturated (PUFA), depending on the amount of double bonds that occur in the carbon chain. Saturated fats have no double bonds. Monounsaturated fats have 1, hence the “mono”, while poly have two or more. The primary type of fat seed oils contain are polyunsaturated. These double bonds are the point of fragility. Double bonds are highly reactive and prone to a process called oxidation, in which the oil reacts with oxygen in the air.  This causes a breakdown of the oils producing unstable molecules that can cause inflammation in our bodies. In terms of reactivity, saturated are the most stable (no double bonds), then monounsaturated which are relatively stable, and polyunsaturated, which are the most reactive. These double bonds become more prone to oxidation under high heat, which happens to be the environment they are placed under during the refining process we mentioned earlier. This is why I made the distinction between oils produced using cold expeller pressing, which does not involve heating the oils, and the heavily refined processes that do. There is a fundamental difference between cold expeller pressed oil and the highly refined, damaged oil mass produced in a factory, even if they originally come from the same whole food source.

 These high heat conditions are also the conditions these oils are placed under when used to fry food in a fast food establishment. Given how efficient the refinement process has become for seed oils, they have become the primary cooking oil in most restaurants these days, as they are simply cheaper than any alternative. Unfortunately, restaurants are not necessarily concerned with or, even aware of, what their food will do to the inflammation status of their customers, and frankly, their customers probably aren’t either. This is the main source of contention in the nutrition space currently. These oils are probably the worst form of fat to be used for high heat cooking, but given how cheap they are, this is what has become the norm. 

These oils are usually high in an oil called linoleic acid, a type of polyunsaturated fat called an omega-6. Another related type of polyunsaturated fat, omega-3, acts as sort of a counter to omega-6 in the body. Both fats are critical for the structure of cell membranes. Too high or too low of one or the other can lead to either too fluid or too rigid cell membranes contributing to inflammation, among a whole host of other problems. There is a delicate balance, a ratio, we need to maintain of these fats for optimal health.  Omega-6 is typically found in plants while Omega-3 is found in high amounts in seafood. (These are not the only sources, some animal products contain small amounts of omega-6 and some animal products and plants contain omega-3, just not to the degree of the “main sources” I mentioned above) Seed oils are often criticized as being inflammatory because an overload of omega-6 relative to omega-3 can promote inflammation. Most western diets have become rich in omega-6 and poor in omega-3, which is the exact opposite of how the human diet was traditionally structured. It is important to point out that it is therefore not the seed oils that are inherently inflammatory, but the composition of the western diet. There is nothing wrong with obtaining omega-6 from seed oils, as long as it is balanced with the proper amount of omega-3.

In terms of safety, there is no evidence that seed oils become contaminated with hexane or any of the other chemicals that are used in the extraction process to any appreciable degree. Say what you want about the FDA, they at least have a handle on whether a food is acutely poisonous or not. The food system in this country is under a high amount of scrutiny and any batches that end up containing any appreciable amounts of toxic chemicals are thrown out. Imagine the public backlash if someone were to be poisoned. In the minuscule chance that were to happen to, you know it would be all over social media, that company would be fined heavily by the FDA, and their reputation would be tarnished. No company producing seed oils would ever risk that. 

One of my main problems with the highly refined forms of these oils is that they are stripped out of the whole food matrix. Many of these oils come naturally packed with other compounds that act as antioxidants (molecules that counter oxidation) protecting the oils from damage. This makes sense from an evolutionary sense. If these plants were going to rely on a highly fragile oil in its seeds, they would need some form of protection. Sesame for example is high in lignans, which protect the oil from oxidation. One of the arguments in favor of whole foods, (and this refers to all categories of foods, not just seed oils) is there seem to be a whole host of natural defense chemicals that our bodies can take advantage of. Every time you hear about a certain food being high in this antioxidant or that flavonol, those are naturally occurring compounds that we can leverage for our own health. In fact, there are some emerging theories that from an evolutionary perspective, we have outsourced the production of many beneficial compounds to the food around us. Why spend the precious energy making it ourselves when there are all these plants around us that already have it? This is one of the arguments for why processed foods in general are so bad. They are just raw forms of calories stripped of the beneficial nutrition they had in their natural form. 

Another point I want to make is that many of the randomized controlled trials that the proponents of seeds oils use as evidence for their argument are usually not able to properly assess the long term impact of consuming a high amount of seed oils. The long term impacts usually take months or even years to manifest. Most of these trials typically range from a few weeks to a few months in length, as anything longer would be way too expensive to justify. There will never be a long term trial looking at the multi-year or decades long effect of consuming a high amount of seed oils. I’m not trying to necessarily make an argument that there would be some sort of harm found if a trial like this were to be done, there just isn’t any evidence there wouldn't be harm. What we do have, though, are long term trials looking at the decades long effect of consuming whole food sources of plant fats. We know to an overwhelming degree that is beneficial. 

I personally choose to limit seed oil consumption not because I think they are necessarily harmful or poisonous, (they do not directly cause inflammation or heart disease or diabetes or whatever dumb shit we see floating around online), I do not see a reason to consume them. You could make an argument to use small amounts of cold pressed sesame oil, walnut oil or something of the sort to use to add certain flavors. I personally have a taste for sesame oil and consume it in small amounts. In terms of the “hateful eight” however, I can’t justify a reason to include them in your diet. These oils are “neutral” in flavor, meaning they do not contribute any flavor to the dish, so why use them over olive or avocado oil? There simply are better options. If you want a cooking oil, why would you use canola oil over avocado oil? If you want a salad dressing, why would you choose sunflower oil over olive oil? And for that matter why would you choose sunflower oil over whole sunflower seeds? These plant oils were designed to be consumed in a whole food form. As a whole food, they contain antioxidants that protect the oil from oxidation, as well as fiber, other beneficial micronutrients such as iron or zinc, etc. Seed oils are still a form of processed food at the end of the day and nobody should be going out of their way to consume more of them. The question here is not, should you consume seed oils, but rather can you justify consuming them over the better options we discussed earlier?

Takeaways

Seed oils can be problematic depending on the context under which they are used and/or the absolute amount. You should opt for expeller pressed oils and should not cook with them. They need to be balanced with an appropriate amount of omega-3 in the diet.  What seed oils are NOT, are “poison”. They are not the reason for the chronic health epidemic. They don't make you fat (unless consumed to excess, in which case that’s just a calorie problem), they don’t give you heart disease or diabetes or dementia or whatever stupid unsupported claims I see floating around on the internet. That being said, you should generally choose to get PUFA’s in a whole food form as they come along with antioxidants that protect the oil from oxidation, as well as many other beneficial compounds. Whole nuts and seeds should be your primary source of Omega-6 PUFA. I do not see a reason to ever choose the “hateful eight” over olive or avocado oil. I could see an argument in favor of certain nut or seed oils used as flavoring agents such as sesame oil or walnut oil, but they should not be used as a primary cooking fat. These seed oils should be seen as a form of processed food and you should limit your consumption of them, just as you would chips, cake, candy, etc.