Seed Oils: Healthy or Harmful?
Seeds are nutrient dense powerhouses. So, by association, it would seem safe to assume that seed oils are healthy too, right? In short — not necessarily. “Seed oil” is a blanket term used to describe any oil made from the seed of a plant. This includes everything from soybean, sunflower, and canola oil to flaxseed, sesame, and hempseed oil. In fact, most vegetable oils are seed oils. But the thing is, not all seed oils are created equal.
There are two definitive categories of seed oils: refined and cold-pressed. As you might imagine, refined (or industrial) seed oils undergo heavy processing. During which, they are bleached, heated, and deodorized, resulting in a rather tasteless, odorless cooking oil that is shelf-stable – just perfect for deep-frying and processing foods. What we’re left with is a nondescript oil that has no real health benefits and, instead, several potential health risks. Cold-pressed seed oils, on the other hand, are made by simply crushing seeds at room temperature. No extra heat or chemicals are required, making them a much healthier option than the aforementioned refined seed oils. As a result, they have higher levels of bioactive compounds (carotenoids, sterols, and phenolics), which means they pack a heartier nutritional punch and have a higher oxidative stability.
But whether refined seed oils are actually bad for you is a controversial topic. You can find arguments for and against consuming industrial seed oils, depending on the keywords you type and the answer you’re looking for. Those arguing in favor say that “there isn't strong enough evidence to say for sure that seed oils are harmful or toxic”. Some even argue that refined plant seed oils are linked to “heart health, decreased risk of diabetes, and lower inflammation.” Those arguing against them point to a whole host of concerns we’ll get into in a second.
The grouping below, sometimes referred to as “the hateful eight” have a reputation (as their name suggests) for being the worst kind of refined seed oils. I’ve even heard them referred to as “engine lubricant.”
Canola oil (aka rapeseed oil).
Corn oil.
Cottonseed.
Grapeseed oil.
Soybean oil.
Sunflower oil.
Safflower oil.
Rice bran oil
So, what are the primary concerns with consuming these heavily refined seed oils? Up first, they have imbalanced omegas. Many seed oils are rich in omega-6 fatty acids, which, when consumed in excess and without sufficient omega-3 fatty acids, are said to contribute to inflammation in the body. The ratio that we actually need of omega-6 to omega-3 is a 1:1 ratio. But the content of most seed oils is somewhere between 10:1 and 20:1 (10-20 times what we actually need). This disproportionate consumption of omega-6 (without enough omega-3) is contributing to the increasing rate of inflammatory diseases (from diabetes and depression to cardiovascular disease and cancer).
The next concern is repetitive heating. Cooking with seed oils at a high temperature and reusing them repeatedly results in a build-up of toxic compounds. Think about restaurants and industrial fryers – how often are those oils changed? Not very.
Then, there are the highly refined processing methods. Most refined seed oils are extracted using high-heat solvents (like hexane), or chemical processes that can lead to the formation of harmful compounds and alter the oil's nutritional properties.
Finally, is the concern of oxidative stability. Polyunsaturated fats found in many seed oils are less stable and more prone to oxidation when exposed to heat, light, and air, potentially forming harmful compounds. This leads to, you guessed it, inflammation.
However, perhaps the biggest concern of all, is the uptick in processed foods since the introduction of seed oils in the early 1900s. In June 1911, Procter & Gamble proudly introduced the very first shortening to be made entirely of seed oil (originally cottonseed oil): Crisco. The success of Crisco catapulted the production of vegetable oils to a whole new level. (Not surprisingly, the Crisco brand is alive and well today.) Under their umbrella, they now market cooking spray and various cooking oils, among them canola, corn, and sunflower oils.
Since the widespread adoption of industrial seed oils, ultra-processed “convenience” foods have soared in popularity. It can be found in everything from crackers, chips, and salad dressing to baby formula and Michelin-starred restaurants. In fact, seed oils today make up 20% of our overall caloric intake. So what can we do about it? For starters, we can do our best to avoid ultra-processed foods. We can read our labels when grocery shopping. When dining out? You’re in luck! I have five helpful tips for that.
As mentioned above, many restaurants use industrial seed oils over higher quality options (like olive or avocado oil) because, well, they are cheaper and can be cooked at high temperatures. So if you’re like me—someone who dines out quite a bit —it’s worth making sure you aren’t consuming heavy amounts of processed seed oils. Here are the five tips for avoiding them when dining out.
Seed Oil Scout: This app maps out restaurants that “care for their customers by cooking with healthy oils and ingredients.” You can search by city or zip code to see if your favorite places play by the rules. They do prompt you to sign up for a seven-day trial (which feels a little scammy), but I’d recommend making a note on your phone to cancel before the trial is up if it’s not for you. Otherwise, it’s $34.99/year (which isn’t terrible if you compare it to the cost of a single meal out). Plus, I’m happy to support those working to make restaurants healthier for all.
Choose grilled, broiled, or steamed: When ordering, look for options that are grilled, broiled, or steamed as foods prepared this way are less likely to use seed oils.
Avoid fried foods: Sadly, fried foods are almost always prepared using industrial seed oils. Fries, calamari, and tempura are obvious examples, but even vegetable sides like brussel sprouts or “crispy” broccoli hang out in the deep fryer at some point.
Be mindful of salad dressing: Ask the restaurant what oil their salad dressings are made with. You can always ask for dressing on the side or request to swap a a dressing you aren’t sure about with olive oil and vinegar.
If you aren’t sure, ask: Okay, yes, I usually feel apprehensive being that annoying, basic B, but it’s always good to ask. You can blame it on a food intolerance (which is true - we would probably all feel better if we consumed less industrial seed oils).
While the jury might still be out on whether industrial seed oils are, in fact, toxic or not, there are plenty of healthy oils to reach for instead. Just in case, I make a point to choose from the five healthy oils below when cooking at home. When shopping for your pantry, look for “cold pressed,” “extra virgin,” or “expeller pressed.”
Olive oil: High in monounsaturated fat, olive oil has been shown to improve blood cholesterol levels when consumed in moderation. Extra virgin olive oil also has one of the lowest oxidation rates of cooking oils out there and is a great source of antioxidants, both of which can help reduce inflammation. Olive oil contains more potassium, calcium, iron and vitamins than avocado oil, making it the most nutritious choice.
Avocado oil: A close second, avocado oil is also high in monounsaturated fat. Like olive oil, avocado oil also contains a high concentration of antioxidants. Avocado oil has a slightly higher smoke point (520 degrees Fahrenheit vs. 410 degrees for EVOO), making it a great option when cooking at high temperatures.
Flaxseed oil: Extremely high in omega-3 fatty acids, flaxseed oil has been said to potentially improve skin health, reduce inflammation, and even reduce cancer cell growth. Unlike olive and avocado oil, though, flaxseed does not have a high point, and, therefore, should not be used for cooking. Better uses include adding it to salad dressing or on top of dishes. You can even use it topically to skin and hair for added health benefits.
Ghee: A staple in Ayurvedic medicine, ghee is clarified butter, which means the milk solids and water have been removed, leaving you with a higher concentration of fat. Because ghee is clarified, it has a higher smoke point (485 degrees Fahrenheit) compared to butter (350 degrees Fahrenheit), making it a healthy choice when cooking at high heat.
Sesame oil: Unlike refined seed oils, sesame oil has a balanced ratio of omega-3, omega-6, and omega-9 fatty acids. High in antioxidants, sesame oil has been said to help improve inflammation and sleep, control blood sugar, enhance hair health, and may even prevent heart disease.
With oils and cooking fats of any kind, it’s important to remember not to overdo it. They do still have a high fat and calorie content and, like anything, are best enjoyed in moderation.
As always, thanks so much for reading!
