Are Seed Oils Bad for You? What the Science Actually Says - and Why Ratio Matters More Than Ingredients
Scroll through social media long enough and you'll find seed oils accused of everything from fuelling chronic disease to being a form of slow-acting poison. The conversation has become so heated that people are swapping out their cooking oils, ditching packaged foods and debating linoleic acid in their lunch breaks.
But here's the most important thing to understand before anything else: not all seed oils are equal. Cold-pressed, unrefined oils are a fundamentally different product to highly refined, heat-processed ones. The debate rarely makes this distinction - and that's where much of the confusion starts.
Are seed oils actually bad for you? The honest answer is: it depends on the oil, how it was made, and what the rest of your diet looks like. The most recent science may also surprise you.
Why Seed Oils Have Become So Controversial
Seed oils - including sunflower, rapeseed, soybean and corn oil - are extracted from the seeds of plants and are widely used in cooking, food manufacturing and restaurant kitchens across the UK.
The controversy centres on one thing: they are high in omega-6 fatty acids, particularly Linoleic acid. Critics argue that omega-6 fats promote inflammation in the body, and that because modern Western diets contain far more omega-6 than ever before, seed oils are driving a rise in inflammatory health conditions.
This narrative has spread rapidly online, picking up momentum from podcasters, wellness influencers and biohackers - some with legitimate concerns, others overstating the case considerably.
The problem is that the science is being selectively quoted on both sides. So let's look at what the research actually shows.
What the Research Actually Says About Seed Oils and Inflammation
In June 2025, researchers presented new findings at NUTRITION 2025, the flagship annual meeting of the American Society for Nutrition. The study, led by Dr Kevin C. Maki, adjunct professor at Indiana University School of Public Health-Bloomington, analysed blood markers from nearly 1,900 people to assess the relationship between linoleic acid levels and indicators of cardiometabolic health.
Their finding was striking: higher levels of linoleic acid in blood plasma were consistently associated with lower levels of inflammatory biomarkers - including C-reactive protein - as well as lower indicators of insulin resistance.
Crucially, the study used objective blood biomarkers rather than self-reported diet records, which are notoriously unreliable. As Dr Maki put it: "People with higher levels of linoleic acid in their blood tended to have a healthier overall risk profile."
It's worth noting that this was an observational study, meaning it identifies associations rather than direct cause and effect - and the researchers themselves called for further intervention trials to build on the findings. But it adds to a growing body of evidence suggesting that the "seed oils cause inflammation" narrative is a significant oversimplification.
These findings align with other large observational studies that have associated higher linoleic acid intake with lower rates of cardiovascular events.
So why does the debate persist?
The Real Issue: Omega-6 to Omega-3 Ratio in Western Diets
Here's where the nuance lives - and where the conversation gets genuinely useful.
The debate about seed oils and inflammation is, at its core, a debate about balance. Omega-6 and omega-3 fatty acids are both essential fats, meaning your body cannot produce them and must obtain them through diet. The problem isn't that omega-6 fats are inherently harmful. The problem is that many people in the UK and wider Western world consume a ratio of omega-6 to omega-3 that is heavily skewed - often estimated at around 15:1 to 20:1, compared to the roughly 4:1 or lower ratio associated with more traditional diets.
When omega-6 significantly dominates, there is less "space" for omega-3 fatty acids to be utilised effectively in the body. The two types of fat compete for the same enzymes and pathways.
The priority, then, is not necessarily to eliminate omega-6 from your diet - the evidence doesn't support that approach. It's to ensure you're also getting adequate omega-3, so the ratio is less skewed. Most people in the UK fall short on omega-3, not because they're eating too much seed oil, but because they're not consuming enough oily fish, flaxseed, walnuts or omega-3 supplements.
Why Not All Seed Oils Are the Same
Another layer the social media debate tends to flatten: not all seed oils behave the same way.
Processing method matters considerably. Cold-pressed or unrefined oils retain more of their natural fatty acid profile and are less prone to oxidation. By contrast, highly refined oils - produced using heat, solvents and deodorisation - may contain oxidation by-products that are harder for the body to handle, particularly when those oils are then used at high cooking temperatures.
Cold-pressed flaxseed oil, for example, is technically a seed oil - but it's predominantly omega-3, and is widely regarded as beneficial. Highly refined, heat-extracted soybean oil used in deep-fat fryers is a very different product.
The debate often treats "seed oil" as a single category. It isn't. Provenance, processing and how you use the oil all matter.
How Udo's Choice Ultimate Oil Blend Addresses the Ratio Problem
Udo's Choice Ultimate Oil Blend was formulated specifically with the omega-6 to omega-3 ratio in mind. It provides omega-3, -6 and -9 fatty acids in a carefully balanced ratio - designed to make it easier to contribute to a more balanced fat intake as part of an everyday diet.
It is made by cold-pressing certified organic seeds and plant oils in a low-heat, oxygen-free environment to protect the delicate essential fatty acids. The oils are blended in a precise 2:1 ratio of omega-3 to omega-6 and packaged in dark glass bottles to minimise light and oxygen damage.
This matters because the quality of the fats you consume is as important as the quantity. Oxidised fats behave differently in the body, and a supplement that has been poorly stored or processed delivers a different product to what's on the label.
Udo's Choice Ultimate Oil Blend is not a replacement for a balanced diet, and it isn't positioned as a treatment for any condition. It's a straightforward way to support a more balanced intake of essential fatty acids - particularly for people who don't regularly eat oily fish (the NHS recommends at least one portion of oily fish per week), who are vegan or vegetarian, or who want to be more deliberate about the fat profile in their diet.
One tablespoon a day, added to a smoothie, salad dressing or drizzled over food after cooking, is one of the simplest ways to support your omega balance.
Summary: What Should You Actually Do?
- The science does not support blanket avoidance of seed oils. A 2025 ScienceDaily study of nearly 1,900 people found higher linoleic acid (the primary omega-6 in seed oils) was associated with lower inflammatory markers, not higher.
- The more meaningful concern for most people is the ratio of omega-6 to omega-3 in their diet - and specifically, low omega-3 intake, not excess omega-6 per se.
- Not all seed oils are equal. Cold-pressed, unrefined oils are a different product to highly refined, heat-processed ones.
- Practical steps: include more omega-3 sources in your diet (oily fish, flaxseed, walnuts), choose cold-pressed oils where possible, and consider an omega supplement if your dietary intake is inconsistent.
This article is for general information and educational purposes only. It does not constitute medical or nutritional advice, and should not be used as the basis for any medical decision. If you have a health condition, are pregnant, or are considering changes to your diet or supplement routine, please speak to a qualified healthcare professional before making changes.
References
Maki, K.C. et al. (2025). Higher plasma linoleic acid is associated with lower cardiometabolic risk biomarkers. Presented at NUTRITION 2025, American Society for Nutrition, Orlando, Florida. Reported by ScienceDaily, 21 June 2025. Available at: sciencedaily.com/releases/2025/06/250621103446.htm