01603 360360

Should We Break Up with Cooking with Seed Oils

bottle of oil with question mark label

You may have heard recommendations, for the sake of your health, to stop cooking with seed oils, such as sunflower oil. The question is why? We did some research to try to get some answers.

The Problem with Seed Oils

Scientist’s main concerns lie with heated dietary polyunsaturated fatty acids (PUFAs). These PUFAs, found in widely used cooking oils like sunflower and corn oil, become unstable at high frying temperatures, typically around 180 degrees Celsius. When exposed to heat and oxygen, these oils degrade, producing harmful lipid oxidation products (LOPs), including toxic aldehydes. A particularly harmful aldehyde, acrolein, is one of these chemicals that can form when these fats oxidise. Acrolein is a potent irritant and highly reactive with biological molecules, contributing to cellular damage and disease.

The Danger of Lipid Oxidation Products

LOPs are not harmless byproducts, they are chemically reactive and can have severe health implications. Here are some of the possible adverse effects:

  • Carcinogenic: These compounds can react with DNA, potentially leading to mutations and cancer. Acrolein, specifically, is known to form DNA adducts, which are significant in the progression of cancerous conditions.
  • Atherogenic: They can modify low-density lipoproteins (LDL), promoting cardiovascular diseases. Acrolein exacerbates this process by contributing to endothelial dysfunction and vascular inflammation.
  • Gastrotoxic: Even in small quantities, these compounds can cause gastric ulcers. Acrolein’s high reactivity also makes it particularly damaging to the gastrointestinal tract lining.
  • Pro-inflammatory: They contribute to chronic inflammation, linked to various diseases. Acrolein itself triggers widespread inflammatory responses.
  • Neurodegenerative Diseases: There is evidence suggesting a role in conditions like Alzheimer’s. Acrolein has been specifically linked to neural damage and is considered a neurotoxin.

Cooking Practices Matter

Professor Martin Grootveld, in his lengthy presentation (found here), pointed out that different cooking methods influence the levels of toxic compounds. For example, deep frying, often considered less healthy due to higher oil absorption, might produce fewer toxic compounds than shallow frying because of reduced exposure to oxygen. However, both methods still pose risks if PUFAs are used.

Alternatives to Consider

Switching to oils with higher monounsaturated fatty acids (MUFAs) or saturated fatty acids can mitigate these risks. Oils like olive oil (high in MUFAs) and coconut oil (high in saturated fats) are more stable at high temperatures and produce fewer toxic byproducts. Standard olive oil is preferred over virgin olive oil if you are going to use it for cooking, by the way. Not only do these oils offer a safer cooking option, but they also do not contribute to the formation of acrolein under normal cooking conditions.

The Bigger Picture

Dr Grootveld also sheds light on the broader health impacts of our diet. He states that with good evidence points towards diet being responsible for 30-35% of cancers, knowing and understanding the components of our food and their effects is a vital step for people trying to reduce their chances of contracting disease. He emphasised that the evidence against the excessive use of PUFAs in cooking is compelling.


sautéed food

Practical Steps

  • Avoid High-Heat Cooking with PUFAs: Opt for oils like coconut oil for frying.
  • Proper Storage: Store oils in cool, dark places to prevent oxidation.
  • Limit Exposure: Use proper ventilation when cooking to reduce inhalation of toxic fumes.
  • Look to adopt less toxic methods of cooking such as boiling and steaming.
  • Question what is in your food and how it is being cooked.
  • Reduce the oil on cooked food by soaking it with paper towels.
  • Avoid reusing cooking oil.
  • Switch out shallow frying for sauteeing.

Your Choices

Yes, seed oils have advantages. They are cheap, they are liquid at room temperature, and you can buy them from any corner shop. These conveniences make seed oil the easier choice, but the potential health risks suggest that it might be time to reconsider their use in our kitchens. By opting for more stable oils and being mindful of cooking practices, we might just be making a great difference towards protecting our health. Putting aside our own cooking for a minute, please bear in mind that takeaway and restaurants are businesses, so unless otherwise stated, they will be using the cheapest frying option when they make your food.

*We have long been advised that our saturated fat intake should be limited, for the sake of our blood cholesterol levels. Please bear in mind that coconut oil (in the form we buy in the shops), whilst being one of the more stable when heated, is 86% saturated and has been shown to raise LDL cholesterol (bad cholesterol) levels, but, it also raises (good) HDL cholesterol levels, we suggest, based on the above, that if you cook with any oil, reduce the amounts.



We are not scientists and looking at oils and diet throws up conflicting arguments. We have the doctor above, who gives convincing arguments for not frying with seed oils in favour of oils like coconut. We have long-standing advice to avoid saturated fat. We invite you to consider the above and if concerned, conduct some more research. At the very least, cutting down on fried food seems like a good idea.


Leave a Comment

Your email address will not be published.

Recent Articles


All our staff have been vaccinated against Covid-19 thus reducing mutual risk. As a Covid-Safe, CQC Registered Medical Clinic with Ventilation that ensures TWELVE air changes per hour your safety is our priority. 

We are continuing to adhere to strict protocols so the car park will continue as our waiting room for the time being. We look forward to welcoming you back!

Feel free to contact us on 01603 360 360 or at info@laserdocs.co.uk.