If you spend any time on social media, you may have noticed that the topic of “seed oils” has popped up a lot lately. Or, more specifically, content suggesting that seed oils are “toxic”, responsible for a range of lifestyle diseases, including obesity and some types of cancer, and calling for these oils to be banned.

While such sensationalised reports may seem convincing, as in all areas of nutritional science, things are a little more complicated when we examine the types of fat we routinely consume, and the effect these fats have on our overall health and disease risk.

What are seed oils?

Seed oils are a type of plant-based fat derived from a range of seeds including sunflower, canola and soybean oil. While the natural seeds offer several key nutrients, the seeds must be heavily processed to extract the oil, remove the flavour and extend shelf life, which reduces the key nutrients seed oil naturally contains, such as vitamin E.

Why are seed oils being targeted?

It is suggested by their online detractors that as seed oils have a high proportion of omega-6 fats, the type known to promote inflammatory pathways in the body, that they are one of the key drivers of the rise of inflammation-related conditions such as heart disease.

What causes inflammation?

Inflammation in the body is not caused by a single food or ingredient. Rather, inflammatory pathways are affected by dietary patterns over time, which determine the balance of nutrients available to the body’s cells. Here, different types of fat compete for uptake by the cells, with diets relatively high in anti-inflammatory omega-3 fats able to balance out the pro-inflammatory effects of omega-6 fats.

It is not specifically seed oils that increase these ratios. Rather, it’s the overall balance of fat in your diet, as well as the total amount of fat consumed overall.

It’s not the seed oil, it’s how we eat it

Closer inspection of your favourite biscuit, cake, pastry or fried food menu will quickly reveal that much of the ultra-processed food supply is riddled with vegetable oil as one of the primary fat-based ingredients used to create the mouthfeel, flavour and nutritional profile of foods.

While seed oils may be specifically used and highlighted, more common are blends of different oils including palm oil, a more saturated and cheaper type of fat.

Nutritionally, these blends are inferior to seed oils, and while seed oils may add omega-6 fats to the diet, vegetable blends also add a higher proportion of saturated fats.

Overall, it is a high intake of these processed foods, along with refined carbohydrates, sugar and poor-quality fats that is associated with increased inflammation, not seed oils in isolation. In fact, seed oils are relatively expensive compared with vegetable oil blends, one of the reasons blends are favoured over sunflower and canola oil.

Getting your fat balance right

When modelling diets to achieve ideal ratios of omega-6 and omega-3 fat in the diet, there is little need, if any, for these processed fats. Rather, getting your daily 60-80g of fat is easily achieved when you include at least three or four serves of oily fish such as salmon or sardines in your weekly diet, along with a handful of nuts and seeds.

When it comes to cooking oil, you can’t go wrong with Australian extra virgin olive oil or avocado oil, both of which offer varieties suitable for cooking, and have extremely high levels of monounsaturated fats, the fats that have a neutral effect on blood cholesterol levels, and may even help to protect against heart disease.

The actual problem

Targeting seed oils as the primary reason for a range of health conditions may sound plausible but when examined more closely, we find that it is not the oil that is the problem.

Rather, it is the foods we like to eat it in – the hot chips at the pub, the fast food and takeaway meals, your favourite chocolate biscuits and potato chips, and the cheeky piece of banana bread with a coffee.

If you are prepared to ditch these foods from your diet completely, you will create the balance that reduces inflammation. But for most people, this is easier said than done.