The controversy around seed oils is complex, but it seems unfair, and against the science, to label them as “bad.”
Seed oils are oils that are extracted from the seed of a plant. Examples of seed oils include canola, corn, flaxseed, grapeseed, peanut, safflower, soybean, and sunflower oil. Using the term “seed oil” and lumping all seed oils together is not the best idea. This is because they are not all created the same or used equally. For example, flaxseed oil is not used in the same way that corn oil is. Additionally, the amounts and types of fatty acids in each oil vary.
Seed oils are receiving a bad rap and messaging in the media. This may lead you to believe they are toxic and should be completely removed from your diet.
That is not necessary. Seed oils can be consumed in moderation as part of a healthy diet.
Common Question and Concerns
Are Seed Oils Inflammatory?
A common concern about seed oils is that they lead to unhealthy inflammation because they contain omega-6 fatty acids.
Omega-6 and Omega-3 fatty acids are both polyunsaturated fats. We can only get these fats from food. These fatty acids are needed to maintain proper health. Omega-6 fatty acids are not only found in seed oils, but also in foods such as nuts, seeds, tofu, edamame, other soy products, and some meat and eggs. In the right amount, omega-6 fatty acids contribute positively to our health. Research shows that omega-6 fatty acids help lower LDL, or harmful cholesterol, and are protective against heart disease. They also provide vitamin E, an important antioxidant, and contribute to cell membrane structure and brain function. As you can see, they play many important roles in our health.
Balance is Important
It’s important to balance omega-6 and omega-3 fatty acids. Most seed oils contain some level of both omega-6’s and omega-3’s. In general, seed oils are higher in omega 6’s than omega 3’s. Research suggests that when it comes to these two types of fatty acids, the proper ratio may be key. A ratio of 2:1 or even 1:1 of omega-6 to omega-3 seems to be the ideal ratio for health. Yet, most people get far too many omega-6 fatty acids and far too few omega-3 fatty acids in their diet. Currently, they average a ratio of more like 10:1 or more. This imbalance can lead to inflammation. While a little inflammation can be a good thing, when there is too much inflammation too often, known as chronic inflammation, it can harm our health in various ways in the long run.
Yet, this does not mean that omega-6’s on their own are harmful, just that we don’t need too many of them. At the same time, we should aim to get more omega-3’s in our diet from foods. Good sources of omega-3’s include fatty fish such as salmon, sardines, flaxseeds, and walnuts. Canola oil even has a decent level of omega-3 fatty acids!
One reason people are likely getting too many omega-6’s in their diet is because of their presence in ultra-processed foods.
The Connection between Ultra-Processed Foods and Seed Oils
Most seed oils are used in and consumed from ultra-processed and fast foods people eat. Yet, most highly processed foods also contain high amounts of added sugar, sodium, and/or saturated fat, among other things, all of which when consumed in high amounts can wreak havoc on health. Research has shown that greater exposure to ultra-processed foods is associated with increased risk for negative health outcomes. So, in this case, it may be less about the seed oil themselves, and more about the high number of processed foods we are consuming that happen to contain them. Getting corn oil from eating a bag of chips is not the same as consuming corn oil to roast vegetables.
If we reduce the amount of ultra-processed foods we eat, we may be able to better obtain a healthy omega-6 to omega-3 ratio, among other health benefits that come with reducing the amount of those types of foods in our diet.
Eat Fewer Processed Foods
Consuming more minimally processed and whole foods such as fruits and vegetables, lean proteins from a variety of sources, such as beans, whole grains, nuts, and seeds, is probably more beneficial than cutting out seed oils entirely.
Using seed oil, such as canola oil to cook fish or sesame oil to toss vegetables for a stir fry, can still be healthy and help contribute to a nutrient rich diet.
How Seed Oils are Processed
Many seed oils are processed and refined. Doing so improves their taste, improve shelf life and ability to cook at higher temperatures. This process can strip them of nutrients. It may also expose the oil to chemicals such as hexane, used as a solvent to extract the oil. While the hexane is evaporated off, there may or may not be traceable amounts remaining.
It is important to note that while seed oils are commonly processed with solvents, other oils may also be refined and processed in this way. Additionally, some seed oils may be extracted mechanically, such as expeller pressed or cold pressed, rather than chemically, eliminating the need for hexane. So, in this case, it is more about the refining process used than about the oil itself.
The Bottom Line
It’s important to remember that we need a variety of foods in our diet to be healthy. All foods can fit. One food may help our health in one way but be harmful when too much is consumed. Another food may have the opposite effect. So, for this reason, moderation and variety are the keys to good health.
