Seed Oils, Inflammation, and Ultra-Processed Foods: What Should We Really be Worried About?
When thinking about our long-term health, we should really be worrying about chronic inflammation and ultra-processed foods. On the other hand, seed oils don’t deserve the hate they have been subjected to. However, like with any nutrition-related issues, nuances and context matter.
What Are Seed Oils?
Seed oils are oils obtained from plant seeds. The most commonly used seed oils in the UK are rapeseed oil and sunflower oil. They are high in unsaturated fats and low in saturated fats. Hence, they are considered healthier than animal fats, such as butter and ghee.
Are Seed Oils Bad for Our Health?
The short answer is no. Seed oils don’t increase inflammation, weaken our immune systems, or raise the risk of long-term diseases.
When used in moderate amounts, while avoiding frequent overheating, seed oils are safe for use as a cooking oil. They are affordable, accessible, and have a high smoke point (they don’t degrade at high temperatures). Additionally, they are also rich in vitamins E and K.
So, why do some people think that seed oils are bad? Let’s break down the myths and facts.
Myth 1: Seed oils increase inflammation
The major concern among critics is an omega-6-fatty acid called linoleic acid found in seed oils. Linoleic acid can convert to another fat known as arachidonic acid, which can promote inflammation.
What the critics don’t mention in their claims is how much linoleic acid actually changes into arachidonic acid. (Probably they don’t know or don’t want you to know!)
Studies show that only 0.3% to 0.6% of linoleic acid converts to arachidonic acid in the body. This fractional conversion is unlikely to increase inflammation or cause any significant health problems. (1)
Myth 2: Omega-6-fatty acids in seed oils blunt the health benefits of the “healthy” omega-3-fats
While it’s true that these two types of fatty acids can have common pathways in the body, it doesn’t necessarily mean that seed oils are bad. If you are concerned about this, you can increase omega-3 intake through your diet or supplementation rather than focus on decreasing omega-6 intake.
Also, omega-6-fats also have anti-inflammatory properties, albeit less than those of omega-3-fats. Having less potent anti-inflammatory properties doesn’t naturally make omega-6 pro-inflammatory or a poison.
Myth 3: Refining process during manufacture of seed oils makes them poisonous
Many critics argue that high heat and hexane (a chemical) used during processing of seed oils pose a health threat. However, heating during processing is brief and the amount of hexane in the final product is in insignificant amounts, both pose no risks to your health. (2)
If you are concerned about the so-called risks of the manufacturing process, you can opt for cold-pressed and expeller-pressed alternatives. However, they are usually more expensive.
Another thing to consider is avoiding repeated heating at high temperatures, which may lead to the formation of trans fats and cancer-causing substances. Fortunately, this isn’t a typical concern when cooking at home.
Are Seed Oils in Ultra-processed Foods Bad for Your Health?
No. Overconsumption of ultra-processed foods is the real problem.
Ultra-processed foods (UFPs) are ready-to-eat/ready-to-heat industrial products that are manufactured in large volumes. The UK ranks second among the nations with the highest consumption of ultra-processed foods based on daily energy intake. (3)
High intake of ultra-processed foods has been linked to a higher risk of many conditions, including obesity, cancer, cardiovascular disease, diabetes, stroke, heart attack, and depression.
Processed foods like biscuits, cakes, chips, muesli bars, muffins, dipping sauces, deep-fried foods, salad dressings, and margarines contain high amounts of seed oils. So, people tend to link seed oils with health risks, while the actual culprit is the overconsumption of UPFs.
UPFs are usually high in salt, sugar, and trans fats. They can increase the risk of health problems, including inflammation by:
- Replacing healthy foods, such as fruits, vegetables, and whole grains
- Causing deficiencies of anti-inflammatory nutrients like vitamins C, D, zinc, magnesium
Also Read: Why Leafy and Green Vegetables Should Be on Every Plate
Besides, non-nutritional components in UPFs, such as emulsifiers and sweeteners, may alter gut microbial balance and lead to inflammation. Lastly, chemicals derived from food packaging or heat treatment may increase inflammation.
What Do Major Health Organisations Say About Seed Oils?
Global health organisations don’t consider seed oils unhealthy or poisonous as portrayed on social media.
For example, according to the British Heart Foundation (BHF),
- There is currently no conclusive evidence that seed oils increase inflammation and the risk of heart disease.
- Seed oils are a healthier alternative to butter, ghee, and coconut oil.
- You can enjoy seed oils in moderation.
Likewise, according to the American Heart Association (AHA) NEWS,
“There’s no reason to avoid seed oils and plenty of reasons to eat them.”
According to the World Cancer Research Fund, there is no strong evidence to suggest that seeds oils increase inflammation or the risk of cancer.
A Note About Inflammation
Inflammation is not bad. A tightly regulated inflammatory response is essential for healing after an injury or infection. However, when inflammation lingers for prolonged periods even when there is no real injury or other stimulus, it can harm us.
Prolonged or chronic inflammation can increase the risk of heart disease, cancer, type 2 diabetes, and other health issues.
The so-called health risks of seed oils appear to have mainly originated from the fact that a fraction of omega-fatty acid in seed oils can convert into arachidonic acid, which is involved in inflammatory responses.
What’s missing in this faulty notion is that less than 1% of dietary omega-6-fatty acid actually turns into arachidonic acid in the body. This is clinically insignificant and poses no real threat to our health.
Key Takeaways
Seed oils are safe for everyday use when consumed in moderation and when you avoid reheating them at high temperatures. Omega-6-fatty acids in seed oils have anti-inflammatory properties and can be safely used as a part of a healthy diet.
References:
- Rett, B.S., Whelan, J. Increasing dietary linoleic acid does not increase tissue arachidonic acid content in adults consuming Western-type diets: a systematic review. Nutr Metab (Lond) 8, 36 (2011). https://doi.org/10.1186/1743-7075-8-36
- Does the processing of seed oils pose a health risk? (n.d.). Eufic. https://www.eufic.org/en/misinformation/article/does-the-processing-of-seed-oils-pose-a-health-risk
- UK Parliament POST. Health impacts of ultra-processed foods. 12 July 2024. https://researchbriefings.files.parliament.uk/documents/POST-PB-0059/POST-PB-0059.pdf
