Low Quality Vegetable Oils: Worse for You than Cigarette Smoking?


Plant-based foods are good for you, so vegetable oils must be healthy since they come from plants right? Although technically not really from vegetables, processed seed oils like soybean oil, corn oil, canola oil, cottonseed oil, and a few others are commonly referred to as “vegetable oils.” It might come as a surprise that these “vegetable oils” aren’t all they are cracked up to be. In fact, they might even wreak disastrous havoc on your health.

Navigating the overcrowded supermarket oil shelf can be a rather daunting task, with each variety claiming to have a different impact on health or imparting various quality factors such as high-smoke point and a particular taste. So how do you know which oils actually do provide health benefits and are considered high quality? Which oils are the best choices for promoting your body’s innate cellular detoxification process known as autophagy? I’ve heard it said that low-quality vegetable oils might be worse for you than smoking a cigarette. What’s the truth in that? Let’s find out.

The Changing Face of Nutritional Benefits Of Oils

The low-fat craze of the 1990’s is about as passé as the shoulder pad fashion that same era gave us. While fats may be calorie-dense, they are necessary for the absorption of fat-soluble nutrients and they aid in satiety. Although current mainstream nutrition advice advocates that we consume less than 10% of our calories per day from saturated fat, the health benefits of consuming the right kind of fats are now receiving lots of attention.

Plants store their excess energy as triglycerides, which are extracted as oils from the seeds or pulp of a wide variety of plants. Each type of oil has a different mix of saturated, monounsaturated, and polyunsaturated fatty acids, a combination that can significantly impact their nutritional benefits. While many of us have been conditioned to think of dietary fat as our enemy, this is simply not the case. The truth is that fat is essential to optimal health — you just need to choose the right kind!

Saturated Fats

Recommendations for limiting dietary saturated fat are due to decades of research suggesting they increase low-density lipoprotein (LDL) cholesterol and increase the risk of heart disease. Typically associated with animal fats such as butter and lard, saturated fats also are found in tropical oils, such as coconut, which has an unusually high proportion of medium-chain triglycerides (MCTs). Different than the long-chain triglycerides that may increase the risk of heart disease, MCTs are sent directly to the liver, where they are converted to energy rather than being stored as fat.

Polyunsaturated Fats

Although studies have suggested the two most common PUFAs, omega-3 fatty acid alpha-linolenic (ALA) and the omega-6 linoleic acid (LA), reduce the risk of cardiovascular disease, the problem is they don’t make the distinction between omega-3 and omega-6. Recommendations to replace saturated fat with PUFAs to reduce cholesterol, has led to an increase in agricultural production of seed oil crops which are high in omega-6 fatty acids. This has caused the typical Western diet to be flooded with omega-6 fatty acids and become low in omega-3 fatty acids — an eating pattern which has been suggested to be pro-inflammatory and may increase the risk for chronic disease.

Monounsaturated Fats

Oils high in MUFA have been linked to lowering LDL cholesterol and triglycerides and raising high-density cholesterol (HDL) or “good” cholesterol levels. Intake of MUFAs can positively affect cholesterol, blood pressure and inflammation and has been linked to a decreased risk of chronic disease and becoming overweight. Examples of MUFA’s include extra virgin olive oil and avocado.

Vegetable Oil Quality

Not all oils are created equal is an understatement. In addition to taste, factors like smoke point, vulnerability to oxidation, and whether they are refined or unrefined should all be considered.

Smoke point

Different oils can withstand varying levels of heat before they start to burn, a phenomenon known as the smoke point. Beyond its smoke point, an oil begins to lose flavor and nutrients, the molecules begin to break down producing free radicals, and toxic fumes are emitted which are the components that can accumulate over time and become precursors to various disease states. Oils with a “high” smoke point are best for searing, sautéing and browning. Oils with a “medium-high” smoke point may be best suited for baking and oven-cooking. “Medium” smoke point oils are best for light sautéing, sauces, and low-heat baking. Oils considered “no-heat” are best for drizzling on dips and using as dressings.

Fatty Acid Oxidation

All fatty acids are susceptible to oxidation which is triggered by exposure to light, heat, and oxygen. The oxidative process limits shelf life and leads to the unpleasant taste and smell of rancidity, it may also raise the risk of cardiovascular disease. As a general rule, the degree of saturation affects the vulnerability of an oil to damage, with saturated fat being the most stable and PUFAs being the most susceptible to oxidation. Like PUFAs, MUFAs are also vulnerable to oxidation unless they are in an oil which also contains antioxidants such as high quality extra virgin olive oil. As a general rule, oils should be capped tightly and stored in a cool, dark place, and those high in PUFA should be refrigerated.

Refined vs. Unrefined

Historically, cooking oils contained no additives or preservatives, and were simply the byproduct of crushing the oily part of the plant. The commercial manufacturing process for mass-market cooking oil now involves cleaning, grinding and extracting all part of the refinement process that relies on chemical substances to remove components that effect taste, smell, and color. The result is generally bland tasting oils with very few nutrients retained and a concern about remaining toxic chemical residue that could potentially damage the nervous system. For example, extra virgin olive oil has undergone limited processing while “pure” olive oil has been highly refined. The difference between virgin and pure olive oil is vast while virgin is slightly green, with a fruity flavor and floral smell, the pure version which has been majorly refined is clear with no taste or odor reminiscent of the ecology it came from.

Although less stable, unrefined oils are minimally processed using the cold or expeller pressed methods which may help retain naturally occurring components that contribute to their health benefits. Terms under the unrefined umbrella include raw and virgin which indicate how many times the material was pressed to get the oil out. Extra virgin means that the oil is extracted from the first pressing only. Typically, unrefined oils taste like the material they were extracted from. Always choose the least refined option available to you when possible.

Choose organic when possible

The quality of the source raw ingredient is important in determining the eventual quality of the end product oil. Because oils are concentrated, any pesticides and other environmental toxins may be concentrated too, for this reason, organic oils are much preferred to their non-organic counterparts.

Thumbs Up or Down?

Some Popular Oils and How to Use Them (or not!)

Although mainstream nutrition and health organizations suggest that unsaturated fats are much healthier than saturated fats, the composition of fatty acids in many so-called vegetable oils is different than any naturally occurring fats we’ve ever been exposed to throughout evolution. We’ve established that most “vegetable oils” contain high levels of omega-6 fats that may be harmful in excess. Many are also genetically modified, for example, canola oil is the result of a genetically modified rapeseed plant which was altered to produce seeds that were higher in the MUFA oleic acid. Oleic acid is one of the most abundant fatty acids found in foods and accounts for 12% of calories in the American diet. Regardless of having a high smoke point and more MUFA than PUFA, canola oil has a whole laundry list of problems on its own. It is anti-nutritive, denatured, highly refined, full of pesticides, full of chemical solvents, and oxidized/rancid.

Vegetable Oils: Virtually all vegetable oils, especially canola, corn, and soybean, go through a process with high heat and chemicals. These chemically altered vegetable oils may have a rancid-like smell. Since these are made primarily of polyunsaturated fatty acids, the nutrients can be damaged by heat or oxidized, before they ever even hit the pan. Overall, I give “vegetable oils” otherwise known as processed seed oils (soybean oil, corn oil, canola oil, cottonseed oil): a thumbs down.
Extra Virgin Olive Oil: Minimally processed and rich in MUFAs, plus protective compounds that prevent oxidation and contribute to its anti-inflammatory effect. It has a fruity, tangy, bold flavor and a medium smoke point for use in oven cooking, light stir-frying or in raw form. Thumbs up!
Avocado Oil: Also rich in MUFA, this oil has a rather sweet aroma and a high smoke point making it a good all-purpose oil. Choose cold-pressed for less refinement and because it contains antioxidants and other beneficial plant compounds. Thumbs up!
Sesame Oil: Although high in PUFA, this oil contains natural antioxidants which make it okay to use for cooking or stir-frying. The bold nutty flavor is popular for use in Asian dishes. It should be kept refrigerated. Unrefined sesame oil gets a thumbs up!
Coconut Oil: Coconut oil is over 80% saturated fat, making it suitable for higher heat cooking. It is natures richest source of MCTs which are sent directly to the liver, where they are converted to energy rather than being stored as fat, plus MCTs have a whole host of other health benefits. Virgin and expeller-pressed typically have the strongest tropical scent and flavor. Double thumbs up!
Tea Seed Oil: I’ve saved the best for last, and right off the bat I’ll give tea seed oil a triple thumbs up as it comes out on top from smoke point to fat oxidation to taste! Tea seed oil is high in MUFA, with a similar fat profile to olive oil but an even higher concentration of antioxidants. In fact, it is often referred to as the ‘Eastern olive oil’ as it is a staple cooking oil in many parts of southern Asia. It is ideal for a variety of cooking applications and can also be used in the raw form. More information on the many benefits of tea seed oil can be found in my new bestselling book Glow15.
Whether you drizzle, splash, or cook with healthy oils, they add satisfying richness and flavor to food, help absorb nutrients, and include a whole host of properties that may be beneficial to your health. Best of all, healthy fats promote autophagy, maximizing its energy and longevity promoting properties. To find out more about how you can use healthy fats to activate your own autophagy grab your copy of Glow15 which outlines my science-based lifestyle plan to a whole new you! In the meantime, start cooking the Glow15 way with these tasty FREE recipes!
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