Why does omega-6 cause inflammation?

October 22, 2025 •

2 min read

According to recent studies, a high dietary ratio of omega-6 to omega-3 fatty acids is strongly associated with an increased risk of chronic diseases like cardiovascular issues. This sheds light on the complex question: why does omega-6 cause inflammation, and what is the underlying mechanism responsible for this effect?

Quick Summary

Excessive omega-6 intake promotes inflammation through metabolic pathways that produce pro-inflammatory signaling molecules. An imbalanced ratio of omega-6 to omega-3 in modern diets can perpetuate chronic, low-grade inflammation.

Key Points

Arachidonic Acid Production: Excessive dietary omega-6 is converted to arachidonic acid, a precursor for pro-inflammatory signaling molecules.
Pro-inflammatory Eicosanoids: Through COX and LOX pathways, arachidonic acid generates inflammatory prostaglandins and leukotrienes that promote pain, fever, and swelling.
Omega-6 to Omega-3 Ratio: The modern Western diet's high omega-6 to omega-3 ratio favors the production of pro-inflammatory compounds over anti-inflammatory ones.
Source of Imbalance: Overuse of omega-6-rich industrial vegetable oils in processed foods is a primary cause of this dietary imbalance.
Balancing the Ratio: Reducing vegetable oils and increasing omega-3-rich foods like fatty fish, flaxseeds, and walnuts can help restore a healthier anti-inflammatory balance.

The Metabolic Pathway: Omega-6 to Arachidonic Acid

Omega-6 fatty acids, with linoleic acid (LA) as a primary source, are essential but often consumed in excess in modern Western diets, largely from industrial vegetable oils. This surplus, particularly relative to omega-3s, creates a biological imbalance. LA converts to arachidonic acid (AA), stored in cell membranes and released during inflammation by phospholipase A2. AA then becomes available for conversion into signaling molecules.

Pro-Inflammatory Eicosanoids: The Culprits

AA is converted into eicosanoids via the cyclooxygenase (COX) and lipoxygenase (LOX) pathways. The COX pathway generates pro-inflammatory prostaglandins and thromboxanes, while the LOX pathway produces leukotrienes that recruit immune cells and constrict airways.

The Critical Omega-6 to Omega-3 Balance

Excess omega-6 not only increases pro-inflammatory eicosanoids but also suppresses anti-inflammatory signals from omega-3 fatty acids (EPA and DHA), which produce anti-inflammatory eicosanoids and specialized pro-resolving mediators (SPMs). Omega-6 and omega-3 compete for the same enzymes, so a high omega-6 diet favors inflammatory pathways. This imbalance contributes to chronic, low-grade inflammation linked to various diseases. Ancestral diets had a roughly 1:1 ratio, while modern diets can exceed 15:1.

Dietary Sources: Omega-6 vs. Omega-3

Correcting the imbalance requires understanding dietary sources.


Feature	Omega-6 Fatty Acids	Omega-3 Fatty Acids
Primary Source	Industrial vegetable oils (soybean, corn, sunflower), nuts, seeds, some meats	Fatty fish (salmon, mackerel, sardines), flaxseeds, chia seeds, walnuts, algal oil
Inflammatory Role	Promotes inflammation via arachidonic acid (AA) pathways	Reduces inflammation via EPA and DHA pathways
Metabolic Competition	Competes with omega-3 for enzymes; excessive amounts skew production toward inflammatory signals	Competes with omega-6; sufficient amounts promote anti-inflammatory signals
Examples	Linoleic Acid (LA), Arachidonic Acid (AA)	Eicosapentaenoic Acid (EPA), Docosahexaenoic Acid (DHA), Alpha-Linolenic Acid (ALA)

Reducing Inflammation: Actionable Steps for a Better Ratio

Balancing omega-6 and omega-3 involves reducing high omega-6 sources and increasing omega-3 intake, not eliminating all omega-6s.

Limit Processed Vegetable Oils: Reduce intake of oils like soybean, corn, sunflower, and safflower.
Choose Alternative Cooking Oils: Use options like extra virgin olive oil or coconut oil.
Eat More Fatty Fish: Aim for fatty fish like salmon or sardines twice weekly.
Increase Plant-Based Omega-3s: Add flaxseeds, chia seeds, and walnuts. Algal oil is a vegan EPA/DHA source.
Consider Supplementation: Fish oil or algal oil supplements can help, but consult a healthcare provider first.

Conclusion: Rebalancing for Health

A balanced omega-6 to omega-3 ratio is crucial for managing inflammation. While essential, excessive omega-6 from processed oils increases pro-inflammatory eicosanoids. This is worsened by low omega-3 intake, as omega-3s normally resolve inflammation and compete with omega-6 pathways. Rebalancing the ratio through diet supports natural inflammatory processes and reduces the risk of chronic, inflammation-driven diseases.

For more on dietary guidelines, the American Heart Association offers insights on omega-6 incorporation for heart health.

Frequently Asked Questions

Experts suggest an ancestral ratio of around 1:1, while the typical Western diet can be as high as 15:1. A lower ratio, generally below 4:1, is considered more beneficial for managing inflammation.

No, omega-6 fats are essential for health and not inherently bad. The problem is the disproportionately high intake compared to omega-3s, which promotes excessive inflammation.

Common culprits include industrial vegetable oils such as corn, soybean, sunflower, and safflower oil, which are used extensively in processed and fried foods.

Excellent sources include fatty fish like salmon, mackerel, and sardines. Plant-based sources include flaxseeds, chia seeds, walnuts, and algal oil, which is a good vegan alternative to fish oil.

Omega-3s, specifically EPA and DHA, compete with omega-6s for the same enzymes. They produce anti-inflammatory signaling molecules (resolvins and protectins) that help actively resolve inflammation, effectively turning down the body's inflammatory response.

No, completely eliminating omega-6 is impossible and unhealthy as they are essential fats. The goal is to rebalance the ratio, reducing excessive intake while increasing omega-3 consumption to promote a healthier inflammatory response.

Supplements can be a helpful tool for increasing omega-3 intake, but they are not a complete solution. It is also necessary to reduce the high intake of omega-6-rich processed foods for the most effective outcome.