Chelsea Newbrough, RDN
Seed oils are in the hot seat, but how concerned should you really be? After all, they're a culinary mainstay, derived from the seeds of natural plants. From sunflower and sesame to flaxseed and canola, these oils boast unique flavors and nutritional profiles. So why all the fuss lately?
What are Seed Oils?
Before we dive into the potential problems, let's go over basic types of fats and where seed oils fit in. At the broadest level we have 2 categories:
Saturated Fats: Often called the "bad" fats, they're solid at room temperature, and mostly derived from animal products like butter, cheese, meat, etc. but also coconut oil.
Unsaturated Fats: The "good" fats, found in things like avocados, salmon, and nuts, but also found in seed oils.
Let's break down unsaturated fats a little more to get to the problem.
Unsaturated fats include:
Monounsaturated fats (MUFA's): These are non-essential fatty acids, because the body makes them, but are still beneficial to consume. They include omega-9's, the redheaded stepchild of the omega family. (Be honest, you didn't know there was a 9.) Oleic acid is the most common one, found in large quantities in seed oils.
Polyunsaturated fats (PUFA's): These include omega-3 and omega-6 fatty acids, essential to get from foods because we cannot produce them on our own. Omega-3 fats include ALA, DHA, and EPA and are essential to just about every function of the body. Their heart-healthy reputation is well earned, and can be found in high quantities in salmon, chia seeds, flax seeds, and walnuts. Omega-6 fats can improve cholesterol and insulin resistance, the most common being linoleic acid found in vegetable oils, nuts and seeds.
Linoleic acid can also be converted to arachidonic acid in the body, which is a building block for molecules that promote inflammation, blood clotting, and constrict blood vessels. Based on this, it is thought that a higher intake of omega 6's may lead to systemic inflammation. The recommend ratio of omega 6: omega 3 fatty acid intake is around 2:1, whereas the average American is consuming ratios closer to 15-20:1. This brings us to the first argument against seed oils, so let's dive in.
Why People Poo-Poo on Seed Oils
Their Makeup: Seed oils have a high ratio of omega 6 to omega 3's as you can see in the chart below. Omega 6's are thought to cause inflammation, so therefor, seed oils are bad, right? Well, not entirely.
The Omega 6-inflammation theory has been debunked according to a review done by the American Heart Association. Very little linoleic acid actually gets converted to arachidonic acid, and increased omega 6 intake was shown to actually reduce markers of inflammation or leave them unchanged. Some studies that have examined the role of omega 6 and omega 3 intake ratio and risk of autoimmune disease, allergies and asthma have highlighted the importance of increasing omega 3's as the most beneficial course of action; not reducing the intake of omega 6's.
The Extraction Game: The extraction process plays a pivotal role in determining the oil's quality. Cold-pressed oils, extracted without the use of heat or chemicals, are often celebrated for preserving the oil's natural flavors and nutrients. Seed oils are often highly processed with heat and chemicals, with the end result lacking in any of the original antioxidants from the seeds they started from.
High-Heat Cooking: Seed oils are a popular choice for cooking due to their relatively high smoke point. However, when oils are heated, they break down and create carcinogenic fumes. When oils are repeatedly heated, such as in a restaurant fryer, they continue to break down and are especially susceptible to harmful oxidation.
Where They're Found: The majority of the seed oils we eat are found in foods that are less than desirable in terms of nutrient content. Fast food, chips, cookies, and just about every highly processed food is going to contain at least one of these oils.
While the omega 6 content of seed oils might not be a deal breaker after all, the high level of processing and carcinogenic byproducts of their use is a valid reason to want to limit them in your diet.
Unveiling the Superstars
There's a huge range of seed oil quality out there, so it's pretty unfair to lump them all in the same category. Let's shine the spotlight on some seed oil superstars that deserve a place in your pantry.
Flaxseed Oil: Rich in omega-3 fatty acids, flaxseed oil is one of the few seed oils that has more omega-3's than omega 6's. Its potential anti-inflammatory properties make it a favorite worthy of mentioning.
Pumpkin Seed Oil: Not the most commonly used oil, but this dark, flavorful oil is bursting with antioxidants. Its unique taste elevates everything from roasted vegetables to pasta dishes.
Key Takeaways
Instead of removing all seed oils from your diet, focus on adding more omega-3's. The low level of omega 3's in our diet has been shown to be the problem, not necessarily the amount of omega 6's. Adding more omega 3's will improve this ratio, plus it's always more fun to focus on adding foods instead of taking them away!
Use all oils in moderation. All oils are high in calories, and even your finest olive oil cold pressed by monks in the Italian countryside should be used in moderation. While olive oil is still a culinary favorite, there's nothing wrong with keeping some seed oils on hand for occasional use.
Focusing on seed oils misses the bigger problem. We're zooming in too far here! It's the dietary patterns that include a high intake of fast food and highly processed foods that we should be trying to get away from, not this one ingredient. If you make an effort to eat more whole foods, you're automatically going to consume fewer seed oils. You have nothing to lose by eliminating them entirely, but it is a lot more realistic to instead focus on healthful foods you can add to your diet.
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