Seed Oils, Omega-6, Omega-3, and Inflammation: Why This Debate Keeps Missing the Point

By: Chase Merfeld MS, RDN, LN, CSR

www.chasingyourhealth.com

Nutrition debates tend to follow a familiar pattern: identify a single ingredient, strip it of context, and blame it for complex health problems.

Right now, that ingredient is seed oils.

According to social media, seed oils are inflammatory, toxic, overly processed, and responsible for chronic disease. It’s a simple story — and that simplicity is exactly why it spreads.

But simple stories rarely survive contact with real science.

When we step back and examine the full body of evidence, a much clearer conclusion emerges:

Seed oils didn’t create poor diet quality. They became a convenient scapegoat for it.

How Seed Oils Became the Villain

Seed oils such as soybean, canola, sunflower, safflower, and corn oil are widely used in the modern food supply. They appear frequently in packaged snacks, restaurant foods, and ultra-processed products.

Because ultra-processed foods are associated with poor health outcomes, seed oils are often blamed by association.

This is a classic nutrition mistake: confusing a marker of a poor diet with the cause of it.

Ultra-processed foods are problematic because they are energy dense, easy to over-consume, low in fiber, low in micronutrients, and engineered for palatability. Seed oils are often present in these foods, but they are not what makes them harmful.

Blaming seed oils while ignoring overall dietary patterns misses the real issue.

The Fat Debate We’ve Already Studied for Decades

Long before seed oils became a social-media villain, nutrition science focused on a much more important question: what happens when saturated fat is replaced with unsaturated fat?

The answer has been remarkably consistent across decades of research:

Excess saturated fat raises LDL cholesterol. LDL cholesterol is a causal risk factor for cardiovascular disease. Replacing saturated fat with unsaturated fats — including monounsaturated and polyunsaturated fats — improves lipid profiles and reduces cardiovascular events.

Seed oils fall into this category as sources of polyunsaturated fats.

This isn’t new science. It isn’t controversial. It’s foundational.

Omega-6 Fatty Acids and Inflammation: The Controversy Explained Honestly

The strongest argument against seed oils centers on omega-6 fatty acids and inflammation. To have a productive conversation, this concern needs to be addressed honestly — not dismissed, but not exaggerated either.

Omega-6 fatty acids, primarily linoleic acid, can be converted in the body to arachidonic acid. Arachidonic acid participates in the production of signaling molecules called eicosanoids, some of which play roles in inflammatory responses.

This biochemical pathway is real.

Under certain conditions — such as extremely high intakes, severe omega-3 deficiency, or supplementation with arachidonic acid — inflammatory signaling can increase.

This is where the concern originates.

However, participating in an inflammatory pathway is not the same as causing chronic inflammation.

Inflammation in humans is tightly regulated. The presence of a biochemical precursor does not automatically translate to systemic inflammation or disease.

What High-Quality Human Research Actually Shows

When researchers study real people eating real diets, the inflammatory seed oil narrative does not hold up.

Across randomized controlled trials, cohort studies, and meta-analyses, increasing dietary linoleic acid does not raise inflammatory markers such as C-reactive protein, interleukin-6, or tumor necrosis factor-alpha. In many studies, higher circulating omega-6 levels are actually associated with lower inflammation.

Replacing saturated fat with omega-6 polyunsaturated fat lowers LDL cholesterol and reduces cardiovascular events and mortality.

If omega-6 fats were truly driving chronic inflammation, we would consistently see worse inflammatory markers and worse clinical outcomes. We do not.

This is why organizations like the American Heart Association continue to recommend polyunsaturated fats, including omega-6s, as replacements for saturated fat.

Why Omega-6 Intake Is High in Modern Diets

Omega-6 intake is high not because omega-6 fats are uniquely harmful, but because of how modern food systems operate.

Omega-6-rich seed oils are inexpensive, shelf-stable, neutral in flavor, and able to withstand high-heat processing. These properties make them ideal for industrial food production.

Ultra-processed foods rely on ingredients that can survive long storage times and repeated heating. Omega-6-rich oils meet those needs, so they are widely used.

As a result, omega-6 intake increases by default in ultra-processed diets.

Why Omega-3s Are Rare in Ultra-Processed Foods

Omega-3 fatty acids — especially EPA and DHA — are chemically fragile. They oxidize easily, break down with heat, light, and oxygen, and develop unpleasant flavors when degraded.

These characteristics make omega-3s poor candidates for industrial food processing, which prioritizes long shelf life and flavor stability.

Instead, omega-3s are found primarily in fatty fish and seafood, flax, chia, walnuts, and certain fortified products or supplements. These foods require intentional dietary choices rather than passive consumption.

This is why omega-3 intake tends to be low in diets dominated by ultra-processed foods.

The Omega-6 vs Omega-3 “Imbalance,” Clarified

Modern diets often contain adequate or high omega-6 intake alongside insufficient omega-3 intake. This creates a relative imbalance — not because omega-6 fats are toxic, but because omega-3 fats are under-consumed.

The issue is not that omega-6 causes inflammation.

The issue is that ultra-processed diets deliver omega-6 fats without fiber, micronutrients, or omega-3s, and that overall dietary pattern increases disease risk.

That distinction matters.

Why We Promote Omega-3s Without Demonizing Omega-6s

Omega-3 fatty acids provide benefits that omega-6 fats do not fully replace, including lowering triglycerides, improving endothelial function, reducing arrhythmia risk, stabilizing plaque, and supporting brain and visual health.

Because omega-3s are rarely present in ultra-processed foods, increasing intake usually requires conscious dietary changes — such as eating more fatty fish or using supplementation when appropriate.

This does not require eliminating omega-6 fats. It requires improving overall diet quality.

The Chasing Your Health Perspective

At Chasing Your Health, we don’t chase nutrition villains. We chase evidence, context, and sustainable patterns.

Seed oils are not inflammatory by default. They are not toxic at normal intakes. They can improve heart health when they replace saturated fat. And they did not create the ultra-processed food epidemic.

Health is built on dietary patterns, not single ingredients.

Final Takeaway

Seed oils didn’t cause chronic disease. They got blamed for the environment that did.

If we want better health outcomes, we need less fear-based nutrition messaging and more clarity about what actually matters.