Is Canola Oil Bad For You? Evidence from Scientific Papers

Canola oil

Edible rapeseed oil is known in the US as canola oil. But is it not just eaten in the US, being so popular around the world, it’s important to consult the research on the potential health effects of consuming rapeseed oil regularly.

Nutritional quality

Let’s first take a look at a new study published in 2023 that ranks the world’s most common edible oils by their nutritional profile. The study examines what each oil is composed of and uses an algorithm to assign each component a score. Each oil’s final score is totalled up, and then the oils are put in order - the higher the score the more nutritious that oil is thought to be. The oil scoring the highest was extra virgin olive oil. Canola did not appear in the list until #17, meaning 16 other oils were found to be more nutritious than canola under this algorithm Source.

Functional health-promoting effects

Just because a lot of oils are found to be more nutritious than rapeseed/canola, it does not mean it is unhealthy. This study for example, concludes that rapeseed oil can have a beneficial effect on diabetes 1 and 2, metabolic syndrome (health problems that increase your risk of type 2 diabetes, heart disease and stroke). The study also notes that if you buy rapeseed oil, you should look for cold-pressed oil—as this will help to preserve some of the functional components that are required for some of the health promoting effects mentioned above.

Linoleic acid content

Many mention canola oil’s linoleic acid content (21%, olive oil is 10%) as a potential downside when looking at its health profile. Linoleic acid is an omega-6 fatty acid, many believe that increasing omega-6 in the diet leads to increased inflammation. The reality is though, epidemiological studies have found evidence to show that dietary linoleic acid reduced inflammation. The jury is still out though as interestingly there is also evidence that omega-6 can reduce the anti-inflammatory effects of omega-3s. All this to say, take online opinions over linoleic acid with a pinch of salt as its health effects and relationships with other fatty acids are not yet understood enough to draw any concrete conclusions from Source.

Negative health effects

Although most of the current published studies point to canola oil being fairly healthy, there is some evidence to the contrary. This study finding that ingestion of canola oil as the only fat source in the diet of certain rats led to a shortened life span when compared to other oils. It’s worth noting that these rats were stroke-prone and spontaneously hypertensive, so very different to the healthy adults that were studied in most other publications. In this study though, the two main negative effects of canola oil were reduced antioxidant activity and heightened oxidative stress. Both of these aspects are improved by high polyphenol olive oil, so those worried about negative effects in canola oil should consider that as an alternative.

Conclusion

In conclusion it seems that the negative online sentiment around seed oils, specifically canola oil, may be overblown. With most studies highlighting positive health effects, and a much lower number of scientific literature published finding negative effects. Our verdict is that although not the most healthy or nutritious, canola oil should be fine to consume as part of a normal diet.