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Are Vegetable Oils Unhealthy?

I’ve heard this claim pretty often from TV doctors and influencers. Public figures like Dr. Oz, Mark Hyman and Dr. Axe have all made a lot of money from these types of claims and I think it needs to be addressed. With claims that vegetable and seed oils contribute to chronic disease, have serious side effects and are toxic chemical warfare on the body, it can be confusing and scary to navigate the grocery aisles. So let’s dive into the claims surrounding vegetable and seed oils and see what the science says.

What are Vegetable and Seed Oils?

Vegetable oils are oils derived from plants. The term “seed oil” is used to refer to oils that are made from the seed of a plant, such as safflower, sunflower, canola and sesame. These oils are made through one of two ways. The first is chemical processing, where the oils are extracted via a chemical solvent, and the second is via an oil mill, where the oil is extracted by crushing the seeds. In both cases the resulting oils are purified and sometimes refined.


One argument is that vegetable oils/seed oils are high in inflammatory Omega-6 fatty acids, specifically linoleic acid. Linoleic acid is converted in the body to arachidonic acid, which is a precursor to something called eicosanoids. Eicosanoids are pro-inflammatory molecules, but that’s kind of the point. Eicosanoids modulate our body’s response to trauma, injury and illness. Without them our bodies wouldn’t have an appropriate immune response. Too much of these Omega-6 fatty acids can have health effects, but that’s the case for anything and everything. That doesn’t make them inherently unhealthy.

The latest research has not found any connection between linoleic acid and an increase in biomarkers of inflammation including CRP, IL-6 and TNF-alpha. In fact, linoleic acid IS associated with a decreased risk of cardiovascular events, cardiovascular mortality and stroke.

Trans Fat Content

Another argument is that the majority of vegetable oils we consume, from packaged processed foods, are hydrogenated and therefore trans fats. This did actually used to be true. The major source of trans fats in our diet used to come from industrially produced partially hydrogenated vegetables oils. However, in 2015, partially hydrogenated vegetable oils were deemed not generally recognized as safe (GRAS) by the FDA due to the negative health effects of trans fats.

As of June 18th, 2018, manufacturers were no longer allowed to add these to food products. For some specific petitioned cases, they FDA allowed time for reformulation until June 18th, 2019. These special cases had until January 1st, 2021 for their products to work their way through distribution. As of today, February 2021, there are no longer partially hydrogenated vegetable oils in the marketplace.

The oil refining process does cause very low amounts of trans fats to form in the oils we use, but I want to note that animal protein and dairy naturally contain trans fats as well. This doesn’t mean you need to avoid oils completely, but rather you should vary your fat intake.

Organic, GMO and Processing

This is an entirely different discussion in and of itself, so I don’t want to deep dive into this right now. All I’ll say about this is that there are non-GMO and organic varieties of vegetable and seed oils, including the highly demonized canola oil, if you choose to go that route. Additionally, if you’re worried about heat or chemical processing, you can always choose to buy cold-pressed oils.


When it comes to baking and cooking, the type of oil you’re using makes a difference. Because they have different molecular structures, they have different smoke points. What does this mean? The more double bonds, which means higher levels of polyunsaturated fats, the lower the temperature threshold. When you subject the double bonds in unsaturated fats to heat, they begin to react with oxygen and form polar compounds that can be harmful to health. Here’s an overview of the most commonly used oils, their smoke points and best uses.

  • EVOO has a relatively low smoke point at 375℉. While it has many health benefits, save this for dips, dressings and finishing off a dish.

  • Light olive oil has the same health benefits as EVOO, but a higher smoke point of 470℉. This can be used for frying, sautéing, grilling or baking, but be aware that it has a stronger flavor that EVOO.

  • Coconut oil has been heavily touted as a healthy alternative to other oils, but its health benefits are still debated. Either way, coconut oil can be used in place of butter in vegan recipes because it is solid at room temperature. Refined coconut oil has a mild taste and a smoke point of 450℉, making it an option for sautéing or roasting. Unrefined, or virgin coconut oil, has a stronger coconut flavor and a lower smoke point of 350℉. This can be an option for low-temperature baking or no-bake recipes.

  • Canola oil has a neutral taste and a moderate smoke point of 400℉. This is a good option for stir-frying, sautéing, grilling, frying, and baking.

  • Refined avocado oil has the highest smoke point of commercially available cooking oils at 520℉, and unrefined avocado oil has a smoke point of 480℉. Because it has such a high smoke point, avocado is a great option for high-heat cooking methods like frying, searing, grilling and roasting. Choose the refined option for a mild, unobstructed flavor.

  • Refined peanut oil is a flavorful addition best used in stir-frying or roasting, with a smoke point of 450℉. The unrefined variety has a smoke point of 320℉, making it best for finishing a dish, or making a dipping sauce.

  • Sesame oil has a relatively low smoke point at 350-400℉, and it’s best used for low-heat grilling and sautéing or dips and dressings.

So What Does This Mean?

As with anything, moderation is key. If your diet is so high in vegetable oils that you’re having legitimate medical concerns, then there’s a bigger issue at hand. You’re likely not eating enough fruits, veggies, legumes and whole grains that provide your body with the nutrients it needs to function properly. No single food is going to cause you a myriad of health problems, unless you’re only eating that one thing.

When we focus on balance, variety and moderation, all foods fit in a healthy diet that provides us convenience as well as enjoyment, and supports our mental, physical and emotional health. If you’re otherwise healthy and eating a balanced diet, then there’s no need to worry about or avoid vegetable and seed oils.


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