Is Rapeseed Oil Unhealthy and Inflammatory?
Rapeseed oil is one of the most widely available and commonly used oils, but is it really good for us, or could adding it to our diets cause more harm than good?
What is rapeseed oil?
Rapeseed oil is derived from the seeds of the rape or rapeseed plant. This gloriously vivid, yellow-flowering plant is abundant in the British countryside throughout the summer. It is the most common cooking oil in the UK and the second most abundant source of edible oil globally.
About 80–90% of the culinary rapeseed oil in the UK is industrialised. Cold-pressed rapeseed oil accounts for about 5–15% of the market, and the organic, cold-pressed version is produced by a single Yorkshire farm, accounting for about 2% of the country's edible rapeseed oil.1
The rapeseed plant belongs to the cabbage family and is closely related to mustard and turnip. Therefore, rapeseed oil is considered a vegetable oil and is increasingly referred to as a ‘seed’ oil. Many oils marketed as simply 'vegetable oil' will mainly consist of rapeseed.
Is rapeseed oil healthy?
Health authorities promote all versions of rapeseed oil, which most people see as healthy. In reality, about 80–90% of the culinary rapeseed oil in the UK is industrialised and only a tiny fraction is organic. It's been stripped of nutrients and contains toxic by-products that worsen when used as directed.
While cold-pressed rapeseed oil is a significantly better product than the industrialised version, our philosophy is, why bother? Many other great oils, such as olive oil, coconut oil, avocado oil, and healthy animal fats, do not have the same issues.
Nutrient breakdown in rapeseed oil
Rapeseed oil’s fatty acid components break down like this:
- Monounsaturated fat: ~61%, mainly oleic acid (like olive oil).
- Polyunsaturated fats: ~28%
- Omega-6 ~21% (linoleic acid)
- Omega-3 ~11% (alpha-linolenic acid)
- Saturated fats: ~7%.
The crude oil contains vitamin E, K, beta-carotene, and other health-promoting compounds, including plant sterols and phenolic compounds, most of which are lost during processing, as we’ll discuss later.2
A little history of rapeseed oil
There are two primary uses of rapeseed oil: industrial and culinary.
Some rapeseed oil is used in the automotive and chemical industries. It is unsafe for human consumption due to its ~40% erucic acid levels, which occur at high concentrations in oils derived from the cabbage family, such as rapeseed and mustard oil. In this article, we’ll focus on the culinary versions of rapeseed oil.
Over generations, UK and European agricultural scientists intentionally bred rapeseed varieties to be lower in erucic acid. By the 1960s, cross-pollination had reduced levels to less than 5%.3 Today, in the UK and EU, legislation sets a maximum of 2% erucic acid in all vegetable oils, but the average appears to be below 0.5%.4
In the 1970s, building on the work already completed in Europe, Canadian scientists further cross-pollinated rapeseeds to lower erucic acid levels to below 2% and then later to below 1%.5 At the same time, they reduced bitter-tasting compounds called glucosinolates to broaden its appeal as a culinary oil. In 1978, the Western Canadian Oilseed Crushers’ Association trademarked ‘Canola’ from the words 'Canadian oil, low acid’ and renamed all the culinary rapeseed in North America.
It wasn’t until 1995 that agricultural corporations released genetically modified (GM) versions of Canola primarily to resist their patented herbicides. Monsanto created a ‘Roundup Ready’ version, and Bayer, then AgrEvo, released a glufosinate-resistant version.6 These companies have since merged. Today, 95–97% of Canola grown in North America is genetically modified.7 In the UK, none of the rapeseed is genetically modified as ‘GM’ crops are not permitted, but other problems with rapeseed oil exist.
Erucic acid
Erucic acid is toxic; there’s no doubt about that. Animal studies, including monkeys, gerbils, rats and pigs, following both short- and long-term exposure have proved that.8 A heart condition called myocardial lipodosis—a condition where fat builds up in the heart muscles—is caused because the heart muscle cells can’t break down erucic acid. It accumulates, gumming up the energy-producing parts of the cell, causing damage and eventually cell death and organ dysfunction.
Nowadays, erucic levels in rapeseed oil are below 1%, so can we forget all about it?
Rapeseed oil is ubiquitous in ultra-processed packaged foods, which comprise most of the British diet, including, and shamefully, the average British toddler’s diet. Children aged between 1 and 3 years may be at risk of consuming above the ‘tolerable daily intake’ (TDI), which begs the question: why not switch to a safer oil wherever you can?9
Most rapeseed oil is heavily processed
Like many edible oils, the vast majority of rapeseed oil is heavily refined, undergoing multiple stages including cleaning, chemical extraction, heating, degumming, neutralisation, bleaching, and finally high heat deodorising to remove unappetising odours. Hexane, the extraction chemical, is a neurotoxin.10 It’s supposed to be removed during heating, but researchers found hexane residues in 36 of 40 edible oil samples.11 Another study found hexane exceeded EU safety levels in all the oils tested.12
Rapeseed oil is about 30% polyunsaturated fats (PUFAs), omega-6 and omega-3, which are so vulnerable to oxidation during processing that it needs ‘blanketing’ by nitrogen gas, then ‘purging’ to remove air and finally ‘spurging’, which reduces dissolved oxygen.
All these steps are necessary to minimise oxidation and lengthen shelf life, but according to analyses, industrialised rapeseed oil still contains oxidised products and other nasties.13
Rapeseed oil degrades during processing, storage and frying, creating toxic by-products including volatile aldehydes.14 These poisonous by-products of frying, something we’re told rapeseed oil is a good choice for, have well-established links with cancer and dementia.15
Nutrient loss
Many of those steps reduce nutrients, including the oft-touted reason to choose rapeseed oil in the first place, vitamin E. Beta-carotene, a precursor to vitamin A, an antioxidant, and chlorophyll are also increasingly destroyed with each step.16
See graph below:
These industrial steps also reduce the omega-3, ALA, by about 2%, which worsens the omega-3 to omega-6 ratio, an unwanted additional issue.17 We’ve discussed this inflammatory trigger in our seed oils pillar article, ‘The Unsaturated Truth: Drop Seed Oils if You Want to be Healthy.’
What about cold-pressed rapeseed oil?
So far, we've been writing about industrialised rapeseed oil, the kind you find in large, clear plastic containers recommended for cooking. Cold-pressed rapeseed oil comes in small, dark glass bottles. It has an artisanal feeling and is correspondingly more expensive than its refined version.
Cold-pressing was already thousands of years old when Socrates philosophised around Ancient Greece. This simple process was done by hand with a pestle and mortar or scaled up with a donkey-powered version. Today, the process is basically the same. Heavy stones have been replaced with hydraulic presses or screws, which slowly crush the rapeseeds keeping the temperature down as the oil extracts.
Cold-pressed rapeseed oil is a much better product than the refined rapeseed or GM canola versions of North America. It retains those nutrients lost in the industrial version. But, when stored at room temperature, these benefits begin degrading, and the overall quality of the oil drops significantly.18 Also, the issue with erucic acid persists whether it's cold-pressed or industrialised. Furthermore, cold-pressed rapeseed oil is about 21% linoleic acid (omega-6)—we have a research article which focuses on the issues with this oil—which is easily damaged under normal storage conditions and is arguably being eaten to excess.
When it comes to fats and oils, stick with healthy animal fats, dairy fats, and time-tested, centuries-old fruit oils, including olive, avocado, and coconut. You can’t go wrong.
References
- Riverford. (2017) Rapeseed Oil. Link
- Wu, Y., et al. (2019). PLoS One, 14(3), e0212879. Link
- Downey & Harvey. (1963). Canadian Journal of Plant Science. Link
- Food Standards Agency. (2022). Link
- Roche, K. J. (2015). University of Nebraska-Lincoln. Link
- Ibid.
- CBAN (2019). Link
- Food Standards Agency. (2022). Link
- Knutsen et al. (2016). EFSA Journal. Link
- Hamilton RJ, Schaffer DH. StatPearls. Link
- Yousefi & Hosseini (2017). J Exp Clin Toxicol. Link
- Samsuri et al. (2020). Int J Anal Chem. Link
- Kasprzak et al. (2020). LWT, 123, 109078. Link
- Saleem & Ahmad (2018). PLOS ONE. Link
- Freis & Vemulapalli (2025). Foods, 14(3), 513. Link
- Freis & Vemulapalli (2025); Gunstone (2011); Saleem & Ahmad (2018). Link
- Wu, Y., et al. (2019). PLoS One, 14(3), e0212879. Link
- Wroniak & Rękas (2015). J Food Sci Technol. Link
