Omega-3 Fatty Acids: Everything You Need to Know (Part 2)

Omega-3 fatty acids are extremely important for human health. These essential fatty acids play a vital role in regulating triglycerides, blood pressure, and the development of the brain and eyes, especially during the prenatal period. While Part 1 of this guide covered what omega-3s are, their health benefits, how to choose a supplement, and proper dosing, Part 2 focuses on dietary sources of omega-3s and why supplementation is often recommended.

Sources of Omega-3 Fatty Acids

Unlike omega-9 fatty acids, the body cannot synthesize omega-3s, making dietary intake—and increasingly, supplementation—essential. The highest concentrations of omega-3s are found in marine foods (fish, fish oil, and algae). However, neither humans nor fish can produce long-chain omega-3s (EPA and DHA). Fish obtain these fatty acids through algae or smaller fish and store them in their fat tissue, making fish an important dietary source for humans.

Short-chain omega-3s (ALA) are found in plant-based foods:

• EPA is most abundant in sardines, herring, salmon, eel, and shrimp.

• DHA is most abundant in algae, sardines, and salmon.

• ALA is most abundant in plant oils, such as flaxseed oil (55%), soybean oil, canola oil, as well as chia seeds and walnuts.

The omega-3 content in fish depends on fat content. Cold-water fish with 5–20% fat—like herring, sardines, mackerel, salmon, and trout—contain higher levels of omega-3s, whether fresh or canned. An exception is tuna, which loses a significant portion of its omega-3s when canned. Low-fat fish, such as sea bass, hake, bream, and cod, contain smaller amounts.

Today, omega-3-enriched foods are also available, such as eggs, milk, yogurt, soy drinks, and bread. Since plant sources mainly provide ALA, which converts poorly into EPA and DHA, vegetarians need to supplement with algae-based EPA and DHA to ensure adequate intake.

Why Choose Omega-3 Supplements?

Besides numerous clinical studies confirming the benefits of omega-3s, several key reasons make these supplements popular:

Imbalanced Omega-6/Omega-3 Ratio

Modern diets have significantly disrupted the omega-6 to omega-3 ratio. Historically, it was roughly balanced, but today it can range from 10:1 to 20:1. Omega-6 fatty acids, found in vegetable oils, seeds, and processed foods, compete with omega-3s for enzymes and produce inflammatory eicosanoids, while omega-3s have anti-inflammatory effects.

Unhealthy Fats in the Diet

Trans fats, present in baked goods, margarine, and fried foods, increase the risk of cardiovascular disease, high cholesterol, elevated triglycerides, and obesity. Omega-3s help mitigate these risks.

Insufficient Fish and Algae Consumption

Most people do not consume enough fish or algae, resulting in inadequate EPA and DHA intake. While plant sources provide ALA, conversion to EPA and DHA is inefficient. Therefore, direct consumption of EPA and DHA through supplements is the most practical way to increase their levels. Studies show that up to 80% of people worldwide do not get enough EPA and DHA.

Contamination Concerns in Fish

Fish, while rich in omega-3s, are increasingly affected by mercury and dioxin contamination. This reduces omega-3 intake from natural sources, making supplements a more reliable option.

References:

• Burdge, G.C., Calder, P.C. Introduction to fatty acids and lipids. World Review of Nutrition and Dietetics (2015): 112:1-16

• Gammone, M.A., et al. Omega-3 Polyunsaturated Fatty Acids: Benefits and Endpoints in Sport. Nutrients (2019): 46

• EFSA. EPA, DHA and DPA related health claims

• AlwaysOmega3s.com

• Intelligent Labs. Difference Between Triglyceride and Ethyl Ester Omega-3 Fish Oil

• Vitaminoteka. Omega-3 Fatty Acids – Mechanisms and Health Effects

• NIH. Omega-3 Fatty Acids Fact Sheet for Health Professionals

• Guasch, E., Mont, L. Diagnosis, pathophysiology, and management of exercise-induced arrhythmias. Nat Rev Cardiol (2017)

• Vranešić Bender, D. Omega-3 Fatty Acids – Properties and Effects, Dietetics (2011)

• Pavazza, L. Omega-3 Intake in Adult Population in Zagreb County (2022)

• Novak, Š. Effects of Omega-3 Fatty Acids on Human Health (2020)

• Cvejić, J.H. Anti-inflammatory Power of Omega-3 and Flavonoid Combination (2021)

• Juhaz, V. Immunological and Anti-inflammatory Activity of Omega-3 PUFAs (2018)