Seed oils have become a hot topic in nutrition debates. The World Cancer Research Fund (WCRF) recently published an article highlighting their benefits by pointing to their high unsaturated fat content and essential omega-6 fatty acids (1). But is it that simple? Emerging research urges us to look deeper and consider how seed oils are processed, their balance with omega-3 fats, and their broader effects on metabolic health.

If you want to make informed choices about fats in your diet, understanding these nuances is crucial. Let’s break down what science really says about seed oils and your health.

The Balance Between Omega-6, Omega-3, and Trans Fats

Omega-6 and omega-3 fatty acids are both essential, meaning our body can’t produce them on its own. The terms omega-3 and omega-6 don’t signify anything symbolic, instead, they refer only to the position of the first carbon-carbon double bond in the fat’s backbone. This influences the shape of a fat molecule, which, in turn, affects its function in the body.

Omega 3’s ease inflammation, inhibit the formation of clots in the bloodstream, and play a role in lowering triglycerides. Omega-6 fats, however, can be converted into arachidonic acid, a building block for molecules that can promote inflammation, blood clotting, and the constriction of blood vessels

Despite the clear role of each Omega in human health, it’s the ratio between them that is really key. Our ancestors likely consumed omega-6 and omega-3 fats in roughly equal amounts (1:1 to 2:1). Today, Western diets often tip the scale to 15:1 or even 50:1, largely due to increased seed oil and processed food consumption (2). This imbalance is what has been linked to heightened inflammation and increased risk of chronic diseases like cardiovascular disease and metabolic syndrome (3). Boosting omega-3s with a whole food, low-carbohydrate diet, and including Omega 3 powerhouses like fatty fish, flaxseeds, and macadamia nuts helps restore a better balance and reduce body-wide inflammation (3,4).

In addition to the omega-6/omega-3 imbalance, manufactured trans fats, regularly found in processed foods, along with Omega 6’s, pose a significant health risk. Trans fats are created when oils are processed with high heat or through a chemical process called hydrogenation. Trans fats disrupt cell membrane fluidity and trigger inflammation, making the problems caused by an unbalanced omega-6 to omega-3 ratio worse. While many countries have reduced or banned industrial trans fats, they can still be present in processed foods and some partially hydrogenated oils, including certain seed oil-based products (5, 6).

Processing Methods and Their Impact on Stability

In addition to their natural make-up of Omega 6s, seed oils undergo industrial refining involving high heat and chemical solvents. Polyunsaturated fats are prone to oxidation, which can produce harmful compounds linked to oxidative stress and inflammation (5). While regulatory standards limit harmful residues, oxidation products formed during processing and cooking remain a concern (6,10,11).

In contrast, fats like extra virgin olive oil, coconut oil, tallow, and butter are less processed and more stable during cooking, potentially offering protective benefits (7).

Ultimately, prioritizing whole, nutrient-dense foods over isolated nutrients supports long-term metabolic health. It’s not just about fats but the bigger dietary picture (8,9).

As we explore the complex role of seed oils in health, it’s important to recognize how inflammation, a key factor influenced by dietary fats, also plays a critical role in cancer development and progression.

Join us at World Nutrition Summit 2025 (WNS2025) to hear from distinguished experts who will share the latest insights on how nutrition, inflammation, and lifestyle choices influence cancer risk and prevention. This is your opportunity to explore the interconnectedness of health and learn how dietary fats, like seed oils, fit into the bigger picture of disease prevention and optimal well-being.

Don’t miss out on this unique chance to deepen your understanding, ask questions, and be inspired by cutting-edge science from global experts.

References

1.       R. Maselli, S. Kefyalew., (2025, May 20). Are seed oils good or bad for our health? World Cancer Research Fund. https://www.wcrf.org/about-us/news-and-blogs/are-seed-oils-good-or-bad-for-our-health/
2.       Simopoulos, A. P. (2002). The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Biomedicine & Pharmacotherapy, 56(8), 365-379. https://doi.org/10.1016/S0753-3322(02)00253-6
3.       Calder, P. C. (2017). Omega-3 fatty acids and inflammatory processes: from molecules to man. Biochemical Society Transactions, 45(5), 1105-1115. https://doi.org/10.1042/BST20160474
4.       Healthline. (2018, October 31). How to optimize your omega-6 to omega-3 ratio. Retrieved from https://www.healthline.com/nutrition/optimize-omega-6-omega-3-ratio
5.       Voon, P. T., Ng, C. M., Ng, Y. T., Wong, Y. J., Yap, S. Y., Leong, S. L., Yong, X. S., & Lee, S. W. H. (2024). Health Effects of Various Edible Vegetable Oil: An Umbrella Review. Advances in nutrition (Bethesda, Md.), 15(9), 100276. https://doi.org/10.1016/j.advnut.2024.100276
6.       Jacob, A. (2013). Balancing Act. Today’s Dietitian, 15(4), 38-42.
7.       Mozaffarian, D., Katan, M. B., Ascherio, A., Stampfer, M. J., & Willett, W. C. (2006). Trans fatty acids and cardiovascular disease. New England Journal of Medicine, 354(15), 1601-1613. https://doi.org/10.1056/NEJMra054035
8.       Frankel, E. N. (2012). Lipid oxidation. The Oily Press.
9.       Guillén, M. D., & Ruiz, A. (2009). Oxidation products from linoleic acid hydroperoxides in heated oils. European Journal of Lipid Science and Technology, 111(5), 441-448. https://doi.org/10.1002/ejlt.200800120
10. Upadhyay, R., et al. (2014). Heated vegetable oils and cardiovascular disease risk factors. Nutrition Journal, 13, 34. https://doi.org/10.1186/1475-2891-13-34
11. Volek, J. S., & Phinney, S. D. (2015). A new look at carbohydrate-restricted diets: separating fact from fiction. Nutrition, 31(4), 393-399. https://doi.org/10.1016/j.nut.2014.09.002