Seed Oils: Are They As Bad As We’re Being Told?

An increasingly hot topic right now, let's weigh in on both sides of the seed oil debate to help you figure out the facts.

Causing quite a divide within the wellbeing space right now, many are slamming seed oils for being incredibly harmful, whereas others are drawing upon the fact there is no credible evidence to suggest they are. So is it another clickbait, social media-fuelled scaremongering or is there some truth in it?

“Seed oils have been getting a lot of air time lately, mainly due to several podcast conversations and the wider discussion around ultra-processed foods at the moment,” says Natalie Burrows, Nutritional Therapist and Clinical Director at Integral Wellness . “This is a concern of mine as we really shouldn’t be using podcasts as a source for direct nutrition or health advice. Yes, podcasts, newspapers and social media can all produce engaging content with quick answers, and I love how they are sparking conversations and curiosity - but we have to appreciate they don’t (or don’t choose to) have the capacity to dive into evidence and draw out the nuances. With this in mind, it’s important to acknowledge that health is personal, and seed oils are a complex area in nutritional science with many nuances,” explains Natalie. Like anything, there are always two sides, so let’s take a closer look at both the negatives… and the positives. 

Perhaps an obvious one but we’ll box it off anyway, seed oils are oils which are derived from different seeds. The ones under the spotlight right now and being dubbed the ‘hateful eight’ are canola (or rapeseed for us in the UK), corn, cottonseed, grapeseed, soy, rice bran, sunflower and safflower but there are others like chia, black seed, flaxseed and hemp. In fact, most vegetable oils are in fact seed oils. 

“They’re usually extracted using high heat or extreme pressure and are often formulated with chemical solvents,” explains Nutritionist, Megan Hallett.

Your Instagram and TikTok feed is likely flooded with content to suggest they are with many citing a few different reasons as to why. The short answer according to Natalie… It depends on how you’re buying and consuming these seed oils.

Seed Oils And Inflammation

A big headline and undeniably one causing quite a stir is that seed oils cause harmful inflammation. Whilst there is some truth there, inflammation isn’t always a bad thing - it is actually a crucial response for both infections and injuries. Seed oils are a rich source of omega-6 - a polyunsaturated fatty acid (PUFA) also known as linoleic acid which supports inflammation within the body. These are very different from omega-3 (or linolenic acid) which is known to be anti-inflammatory and often hailed a hero. Since both omega-3 and omega-6 cannot be produced by our bodies, they need to be obtained through the foods we eat. “The trick is to get a healthy balance of both to reap both the positive inflammatory and anti-inflammatory benefits of both but most could certainly benefit from upping their omega-3 intake through fatty fish and nuts,” adds Megan.

“To say seed oils are bad for us simply because they are pro-inflammatory is a massive oversimplification,” adds Natalie. Omega-6 can help lower cholesterol and reduce the risk of heart disease (hello, olive oil ), whilst omega-3 can help support both heart and brain health (cue, oily fish ). The key issue here is the overconsumption of pro-inflammatory omega-6 and the lack of anti-inflammatory omega-3. “This is something that has become really prevalent over time due to a change in our modern-day diets,” adds Natalie. “Another huge oversimplification is that we cannot associate an increase in conditions like cardiovascular disease with seed oils alone as we are missing out on the conversation around sugar, alcohol and living more sedentary lifestyles too (just to name a few things that contribute to poor cardiometabolic health). We must remember that correlation and causation are not the same thing,” she adds.

The Ultra Processed Nature Of Seed Oils

There is also a lot of negativity around the way in which seed oils are produced since they can be heavily processed and refined. These processes often strip away the beneficial nutrients, such as vitamin E and antioxidants, that would otherwise be present. Seeds oils are commonly bleached and deodorised to improve their taste, colour and shelf life, but this can further diminish they health benefits they may once have had. “There is also some warning around heating seed oils to high temperatures, particularly when reused multiple times (such as in restaurant fryers),” adds Megan. “This can then lead to the formation of toxic, pro-inflammatory compounds like polycyclic aromatic hydrocarbons (PAHs), some of which are potentially carcinogenic and can cause increased health risks.”

Since seed oils are often crammed into ultra-processed foods, this is another reason they’re getting a bad name for themselves. Again, this is another oversimplification since it’s not the seed oil alone that is the issue here, but rather the inclusion of other potentially harmful ingredients combined with a lack of nutritional value.

As a big part of the seed oil debate is how we are consuming seed oils, it’s good to acknowledge that if you’re sourcing a good quality seed oil and using it in the right way, there can be positives. “There are several studies ( like this one ) to show evidence of seed oils being great for cardiometabolic issues like cardiovascular health, heart disease, cholesterol, fatty liver, insulin resistance and type 2 diabetes,” explains Natalie.

Certain seed oils like flaxseed or chia for example, are in fact rich in omega-3 fatty acids so are known to help support brain health, lower cholesterol levels and reduce inflammation. Others such as sunflower and pumpkin seed oils can be a good source of both vitamin E and antioxidants which can help to protect against oxidative stress and reduce the risk of chronic disease.

“Look for cold-pressed and organic versions of specific seed oils themselves as these won’t have been processed by heat,” suggests Megan. “A good way of identifying these is to look for the ones in dark, glass jars as these ensure the oil is protected against heat and light,” she adds. That being said, do take a moment to consider why you’re choosing that specific oil as there can often be a wiser alternative. For example, extra virgin olive oil is a great source of monounsaturated fats, which is also high in antioxidants and vitamins.

Next, turn to how you’re using these oils. As we now know, one of the biggest issues with seed oils is how they’re made and modified “How you cook with a cold-pressed, organic or locally-sourced seed oil at home is entirely different to picking a processed food containing it,” adds Natalie. I’ll often buy rapeseed oil from a local farmer and cook with it at home or use it cold to dress a dish. I’m not using it at extreme heat or reheating, which hugely reduces the chance of oxidation and, therefore, the potential harmful effects and retains the beneficial PUFAs compounds. Once we can appreciate cooking from scratch, on low heat and using ingredients as close to the source as possible, we can make healthier decisions,” she adds.

Seed oils themselves aren’t necessarily the issue, but consuming them in ways in which they have been impacted by oxidation (due to temperature and reheating) and often through too many ultra-processed foods can be. If you do use them, use the good quality ones we mentioned and do so sparingly, keeping room for other beneficial oils in your diet also. We’re all for things in moderation, supporting your body with good healthy habits most of the time so that a little here and there won’t do any harm.