If you spend much time on wellness Instagram, you’ll no doubt come across some influencer or nutritionist who says seed oils are responsible for chronic health conditions. So, what’s the truth behind the scare stories?
Seed oils are everywhere. From the sunflower oil your crisps were fried in to the rapeseed oil you cook with at home, seed oils are one of the most common ingredients we consume. On the whole, we think of them as being healthy (rich in omega-3 and vitamin E) and they have the added benefit of being relatively cheap. You might fork out for the extra virgin olive oil you drizzle over salad, but no one wants to spend a fiver to cook onions.
But despite their benefits, seed oils are the latest casualty of scaremongering on wellness social media. If your Instagram is anything like mine, you’ll have been served a stream of infographics detailing the ways in which seed oils are making us sick, videos by nutritionists warning clients against oat milk that’s made with oil and guides to avoiding seed oils in restaurants.
We know that eating too much fried food isn’t good for us. Consuming large quantities of saturated and trans fat is linked to an increased risk of heart disease and stroke. But healthy fats, usually found in plants and fish, keep our hearts healthy. And according to the NHS, key sources of those heart-loving monounsaturated and polyunsaturated fats include rapeseed, sunflower and corn oil.
So where’s the online hysteria about seed oil damage coming from? In one post I got served, an influencer claimed that seed oils “are highly inflammatory”, and that they’re linked to “chronic inflammatory diseases and a large variety of other skin, gut and weight issues” including infertility, asthma and arthritis. They even crack a joke, saying: “He’s a 10… but he cooks with seed oils because it’s ‘heart healthy’. (Paid for by the American Heart Association that receiving (sic) funding by the canola oil producers association to say that.”
Another influencer, this time a ‘holistic health’ expert and olive oil enthusiast, claims that “there’s no need to just put up with seed oils at restaurants – they are dangerous to your health”. They advise people to find ‘safe’ options when eating out, such as sushi, grilled meat or fish, baked potatoes and steamed rice and veggies.
It all sounds a bit tin hat, right? Are restaurants really out to harm their customers? Is Big Canola really conning us into thinking that seed oils are heart healthy, when they’re actually trying to make us sick?
What exactly are seed oils?
“Simply put, seed oils are made from oil that is extracted when seeds are crushed,” explains Rhiannon Lambert, registered nutritionist and author of The Science Of Nutrition. “These are often used in cooking for frying and roasting as they have a much higher smoke-point compared to olive oil, which is mainly used in lower-temperature cooking, dressing or marinating. The smoke point refers to the temperature range at which they degrade and may release potentially harmful compounds.”
Other forms of oil, like coconut and olive, crush the fruit or flesh, rather than the seeds.
Are seed oils actually dangerous to consume?
“This line of thinking originated in the US,” explains Alex Glover, senior nutritionist at Holland and Barrett. “One argument against consuming seed oils is that they contain fatty acids such as omega-6, which can raise blood pressure (leading to potential heart attack or stroke) if you consume too much over a long period of time. However, as with everything, consuming within the recommended daily intake isn’t problematic and can actually have positive health benefits – helping with blood cholesterol levels and promoting a healthy heart.”
As with all good conspiracy theories, there’s always a grain of truth. Glover tells Stylist that the more common argument on social media is that canola and soy are ‘toxic’. “According to the Harvard School of Public Health, however, there is no scientific evidence to support these claims,” he says.
“It is true that many foods that use seed oils (eg processed snacks) aren’t exactly healthy, but they also tend to be high in refined carbohydrates, sodium and sugar, which are more likely to lead to negative health outcomes.” He also says that repeatedly heating unsaturated fats (like seed oils) to high temperatures (eg deep fat fryers) is a health concern but that “it’s not believed cooking with seed oils at home is an issue”.
Lambert covers the topic of oils in her book: “While no foods should be off limits there are foods in which we should be mindful of our consumption to help reduce the risk of certain diseases.” Again, she says that the omega-6 content of oils like sunflower oil has been linked to inflammation in large quantities, but that in moderation, they “can help reduce cholesterol levels”.
“However, seed oils like rapeseed oil are actually a good choice for a heart-healthy daily cooking oil as they contain a combination of unsaturated fats, and so should be included as part of a healthy and balanced diet.”
Should you avoid plant milks that contain seed oils?
As a vegan, perhaps the biggest and most worrying concern I’ve seen being spread – usually by trusted, registered nutritionists – is that plant milks made with seed oils should be avoided. As someone who gets through two cartons of Oatly (contains rapeseed oil) and Wunda (sunflower oil) milks a week, I’ve been wondering whether my diet is actually as healthy as I thought it was.
But Glover is quick to dismiss the scare stories: “There is no sound evidence that seed oils that contain omega 6 fatty acids are damaging to health, and this narrative is not based on credible scientific data. Omega 6 fatty acids are involved in pro-inflammatory processes like the production of arachidonic acid and other eicosanoids, but this does not mean consuming seed oils are inflammatory. You shouldn’t be avoiding any food because it contains seed oils.”
Lambert also says: “Plant milks are often fortified with vitamins and minerals, such as calcium and vitamin B12, to help increase their nutritional value. While they may contain seed oils within them, it’s a very small amount, and we do still need some omega-6 fatty acids as part of a balanced and healthy diet, as they play a role in helping reduce cholesterol levels within the body.”
Benefits of eating and using seed oils
“Seed oils are often less expensive and have a much higher smoke point than other oils, which makes them more suitable for everyday use and for cooking at higher temperatures. We just need to be mindful and make sure that we are consuming smaller amounts of things like sunflower oil,” Lambert confirms.
And in fact, there are benefits to consuming things like sunflower and rapeseed oil – and not just from a nutrition perspective. Sure, black seed oil can help to lower blood pressure, but Glover points to the fact that seed oils are now really common in beauty regimes too.
“Marula oil, for example, contains two different kinds of amino acids, L-arginine and glutamic acid, which are proven to help hydrate and reduce the appearance of visible ageing, including fine lines and wrinkles. As it’s rich in fatty acids, it is a natural moisturiser and can help naturally soothe the skin and reduce the appearance of blemishes.”
While Instagram might be alive with apparent experts warning people against the dangers, there are any number of studies out there confirming the health benefits of seed oils.
One, published in the journal Nutrition Reviews, found that the data available revealed “substantial reductions in total cholesterol and low-density lipoprotein cholesterol (the unhealthy kind), as well as… improved insulin sensitivity, compared with consumption of other dietary fat sources”.
Another study got 24 people to eat a diet rich in high oleic sunflower oil for eight weeks, and found that they had significant increases of good cholesterol compared to a diet without sunflower oil.
Black seed oil has been found to reduce the level of oxidative stress in some people with liver injuries, while clinical trials have suggested it might help with colitis, pancreatitis and other gastrointestinal disorders.
What’s the healthiest way to eat seed oils?
Go for cold-pressed
Glover recommends looking out for oils that have been ‘cold-pressed’: “This means they have been produced with no chemicals or solvents which can be present in mass-produced products you may find in the supermarkets.”
Use in moderation
“Try to avoid overusing them when frying food at home and instead add to salad dressings or roasted vegetables”. That doesn’t mean avoiding oil when frying, but more avoiding deep-frying food and diversifying your diet so that your go-to means of cooking isn’t always using a frying pan.
The point here is that it pays to keep an open mind when reading alarming nutritional information on social media. Within the murky world of nutrition, you can just scrape together enough evidence to back whatever diet or philosophy you want to push – and most scares do contain a kernel of truth, even if it’s coated with a hefty dose of misinformation.
Don’t fall for the coconut oil hype
The irony of all this anti-seed oil sentiment is that most advocates seem to push coconut oil as a ‘healthy’ alternative. Again, it has some health properties and it’s great as a plant-based substitute for butter in baking, but it’s pure saturated fat that has been shown to raise cholesterol levels more than rapeseed oil. Even the British Heart Foundation warns people to only use small amounts and opt for unsaturated oils as an ‘everyday choice instead’. If you like coconut oil, eat it… but let’s bury the whole ‘coconut oil is natural, seed oils are dangerous’ rhetoric.
Miranda Larbi is the editor of Strong Women and Strong Women Training Club. A qualified personal trainer and vegan runner, she can usually be found training for the next marathon, seeking out vegan treats or cycling across London on a pond-green Tokyo bike.