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# Omega-3 Fatty Acids

o·me·ga-three fat·ty ac·ids - oh-MEG-ah three FAT-ee AS-idz

## Definition

Omega-3 fatty acids are a family of polyunsaturated [fats](/glossary/lipids) that are essential for human health - meaning your body cannot produce them and they must be obtained through diet. The three most important omega-3s are ALA (alpha-linolenic acid, found in plant sources like flaxseeds, chia seeds, and walnuts), EPA (eicosapentaenoic acid, found primarily in fatty fish), and DHA (docosahexaenoic acid, also found in fatty fish and critical for brain structure).

Omega-3 fatty acids are incorporated into cell membranes throughout the body, where they influence membrane fluidity, cell signaling, and gene expression. EPA and DHA are particularly important for their [anti-inflammatory](/glossary/anti-inflammatory) effects - they serve as precursors to specialized pro-resolving mediators (SPMs) that actively resolve [inflammation](/glossary/inflammation) rather than simply suppressing it. DHA is a major structural component of the brain and retina, making up approximately 40% of the polyunsaturated fatty acids in the brain.

The modern Western diet tends to be disproportionately high in omega-6 fatty acids (found in vegetable oils, processed foods, and grain-fed meat) relative to omega-3s, creating an inflammatory imbalance. While the ideal omega-6 to omega-3 ratio is debated, most experts agree that increasing omega-3 intake - whether through fatty fish consumption (salmon, mackerel, sardines, herring) or supplementation - is beneficial for most people.

## Also Known As

Omega-3s Fish oil Essential fatty acids 

## Key Facts

-   • The three main omega-3s are ALA (plant-based), EPA (anti-inflammatory), and DHA (brain and eye structure). 
-   • The American Heart Association recommends eating fatty fish at least twice per week for cardiovascular benefits. 
-   • DHA makes up approximately 40% of polyunsaturated fatty acids in the brain and 60% in the retina. 
-   • The typical Western diet has an omega-6 to omega-3 ratio of 15-20:1, while ancestral diets were closer to 1-4:1. 
-   • Fish oil supplements are the third most commonly used dietary supplement in the United States. 

## How It Relates To Your Health

Omega-3 fatty acids have the strongest evidence base for cardiovascular protection - reducing triglycerides, lowering blood pressure slightly, reducing the risk of arrhythmias, and slowing the progression of atherosclerosis. They are also studied for benefits in depression, [ADHD](/conditions/adhd), [rheumatoid arthritis](/conditions/rheumatoid-arthritis), dry eye syndrome, and cognitive decline.

If you don't regularly eat fatty fish, your doctor may recommend an omega-3 supplement. Prescription-strength omega-3s (like icosapent ethyl) are FDA-approved for treating very high [triglycerides](/glossary/triglycerides) and have shown significant [cardiovascular](/glossary/cardiovascular) event reduction in clinical trials. Over-the-counter fish oil supplements vary widely in quality and EPA/DHA content.

## Related Terms

[Anti-inflammatory](/glossary/anti-inflammatory)[Lipids](/glossary/lipids)[Triglycerides](/glossary/triglycerides)[Saturated Fat](/glossary/saturated-fat)[Macronutrients](/glossary/macronutrients)

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## Sources

1.  [Omega-3 Fatty Acids](https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/) - National Institutes of Health Office of Dietary Supplements
2.  [Omega-3 Fatty Acids and Heart Health](https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/fish-and-omega-3-fatty-acids) - American Heart Association
3.  [Omega-3 Fatty Acids: An Essential Contribution](https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/omega-3-fats/) - Harvard T.H. Chan School of Public Health

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