Staying on top of which oils are good for you and which oils to avoid can be confusing.
On the one hand, you have sources like the National Health Service (NHS) saying that polyunsaturated fats (which are the main fat in vegetable oils) are good for your heart.[*] On the other hand, plenty of research links excess vegetable oil consumption (including heated oils) to obesity, inflammation, and cardiovascular disease.[*][*][*]
We’ll go with the science on this one. Vegetable oils are harmful to your health.
But that doesn’t mean it’s time to throw out all the cooking oils sitting in your cabinet. Instead, you need to be mindful of understanding which cooking oils are detrimental to your health and which ones can provide heart-healthy benefits.
Why is Vegetable Oil Bad for You?
Vegetable oil comes from nuts, fruits, seeds, and cereal grains. It started becoming prevalent in food preparation in the early twentieth century when it was sold as a replacement for animal fats. (If you’ve ever seen “Crisco” listed as an ingredient in family recipes, that’s the original vegetable oil).
When it was introduced, replacing animal fats with vegetable oil made sense. It was cheap and easy to store with a neutral flavour.
As time went on, various organisations started promoting the replacement of saturated fats (i.e., butter) with omega-6 fatty acids (i.e., vegetable oil) as a healthy decision. However, more recent research suggests the opposite, claiming that consuming saturated fats is not associated with a higher risk of cardiovascular disease or heart attack.[*][*]
The main problem with most vegetable oils is that they contain linoleic acid, a particularly dangerous omega-6 Polyunsaturated fatty acid (PUFA).
Now, having some omega-6 fatty acids is healthy. In fact, research tells us that humans have historically maintained around a 1:1 ratio of omega-3 acids and omega-6 acids, which is optimal for our health.[*]
However, the typical Western diet has distorted this ratio to the point that we’re more likely to have a 20:1 ratio of omega-6 acids to omega-3 acids, putting us at a higher risk of obesity and other serious diseases.
Linoleic acid is particularly harmful because it can lead to excessive inflammation throughout the body, leading to a number of chronic illnesses.[*]
The inflammation linoleic acid causes is due, in part, to the fact that it oxidises when exposed to high temperatures.[*] This means the cooking oil reacts to oxygen, creating chemical compounds that can be detrimental to your health.
Naturally, when you cook with vegetable oil, you heat it to a high temperature. Unfortunately, that means you can’t cook with vegetable oil without also oxidising the linoleic acid inside it.
Avoid These 7 Vegetable Oils
Before you start feeling smug about the fact that your pantry is free of bottles of the oils listed here, recognise that you could be consuming vegetable oil without realising it. For example, salad dressings, margarine, and other processed foods often contain these oils. Even crisps, sauces and pestos from the supermarket are rammed with these oils too!
So, check the labels on items sitting in your cupboards, and toss anything that lists any of these seven most unhealthy vegetable oils as an ingredient.
Safflower oil is hands down the worst vegetable oil you can consume because it’s made up of as much as 70% linoleic acid [*]. There are virtually no nutrients in it. Consuming safflower oil has been shown to increase inflammation and your risk of developing heart disease.[*][*]
You can find four types of sunflower oil on the market, with linoleic acid levels of more than 60%.[*] Sunflower oil has been found to increase your risk of developing chronic diseases, including cancer, and speed up the ageing process.[*] In addition, it’s often used in industrial frying, which is particularly harmful because it will release potentially toxic compounds when repeatedly heated to high temperatures.[*]
This is the oil that was initially used in Crisco. Cottonseed oil is still a favourite for many restaurants that use high-heat cooking because it doesn’t add any additional flavours to cooked foods. But cottonseed oil still packs unhealthy levels of linoleic acid, over 50%.[*]
Soybean oil is cheap, which means it’s used a lot in the US and UK. Unfortunately, it’s also harmful and is about 55% linoleic acid.[*] Researchers have found that, in addition to contributing to obesity and diabetes, soybean oil can impact our brains and affect neurological conditions like Alzheimer’s disease, depression, and anxiety.[*]
Corn oil contains 57% linoleic acid and is high in phytosterols, i.e., the plant version of cholesterol. Phytosterols have been linked to an increased risk of heart disease, especially among postmenopausal women and men.[*][*] Additionally, having 50 – 100 times the average amount of phytosterol leads to a condition known as sitosterolemia, which can cause young people to develop heart disease.[*]
The nutty flavour of peanut oil makes it popular for certain fried foods. However, it is high in linoleic acid, clocking in around 30%.[*] It’s also relatively rich in vitamin E, which has some benefits, such as supporting your immune system and reducing inflammation. But the pros don’t outweigh the cons here. You can get vitamin E from more nutritious foods, such as avocados and pumpkin.
Canola oil (also known as Rapeseed in the UK)
Canola oil (Rapeseed oil) is the least offensive of the top vegetable oils to avoid, with only 20% linoleic acid.[*] However, that’s still too much when there are better alternatives. Plus, canola oil also includes harmful compounds, like erucic acid, which can impair liver and heart function.[*][*]
Ensure that you also avoid any labels that just say “Vegetable Oil” as this could be a blend of any of the above oils.
Try These Healthy Alternatives to Vegetable Oil
The food you consume should nourish your body and in our opinion, help you thrive!. Avoid the above seven vegetable oils when you cook and choose healthier alternatives instead like ghee, tallow, avocado oil, coconut oil, MCT oil, and olive oil.
You don’t need to consume these oils straight to get the benefits. For example, add a few teaspoons of MCT oil to your morning smoothie to start your day with some healthy fat. Spice up your next dinner with chipotle and lime avocado oil mayonnaise, or swap your salad dressing for Greek olive oil dressing (which also makes a fantastic marinade).
No matter how you use them, you’ll reap several health benefits by introducing these healthy fats to your diet. Avocado oil and olive oil are high in monounsaturated fats, which reduce cardiovascular risk and lower blood pressure and blood glucose.[*] MCT stands for medium-chain triglycerides. It’s commonly extracted from coconut oil and is useful for promoting a fat-burning state called ketosis.
Living a healthy lifestyle doesn’t mean avoiding fats. It means choosing healthy fats over unhealthy fats. Your body will thank you for it.
All information provided on our website and within our articles is simply information, opinion, anecdotal thoughts and experiences to provide you with the tools to thrive.
It is not intended to treat or diagnose symptoms and is definitely not intended to be misconstrued for medical advice. We always advise you seek the advice of a trained professional when implementing any changes to your lifestyle and dietary habits.
We do however recommend seeking the services of a trained professional who questions the conventional wisdom to enable you to become the best version of yourself.