Is there a difference between omega-3 and omega-3 fatty acids? The Definitive Guide

December 31, 2025 •

4 min read

The human body is unable to produce essential omega-3 fatty acids on its own, which is why we must obtain them from our diet. The good news is that the terms “omega-3” and “omega-3 fatty acids” refer to the exact same family of polyunsaturated fats.

Quick Summary

The terms omega-3 and omega-3 fatty acids are synonymous and used interchangeably. The critical distinction is among the different types of omega-3s, such as ALA, EPA, and DHA.

Key Points

Synonymous Terms: "Omega-3s" is simply a shorthand for "omega-3 fatty acids," with no difference in meaning.
Three Main Types: The crucial distinction is between the three primary omega-3 fatty acids: Alpha-Linolenic Acid (ALA), Eicosapentaenoic Acid (EPA), and Docosahexaenoic Acid (DHA).
ALA Sources: ALA is the plant-based omega-3, found in foods like flaxseed and walnuts.
EPA & DHA Sources: EPA and DHA are marine-based, primarily found in fatty fish, fish oil, and algal oil.
Important Functions: EPA supports anti-inflammatory processes, while DHA is a key structural component of the brain and retina.
Inefficient Conversion: The body converts ALA to EPA and DHA, but this process is inefficient, making marine sources or supplements important for optimal intake.
Essential Nutrient: Omega-3 fatty acids are essential fats, meaning the body cannot produce them and must acquire them through diet.

The Simple Answer: No, They Are the Same

For anyone asking, “is there a difference between omega-3 and omega-3 fatty acids?”, the answer is a straightforward no. The phrase “omega-3s” is simply a common abbreviation for the more formal scientific term, “omega-3 fatty acids”. This is similar to how the term “B vitamins” is used to refer to the group of B-complex vitamins, or how “carbs” is shorthand for carbohydrates. In both casual conversation and scientific literature, the terms are interchangeable.

The real nuance and confusion often arise when discussing the specific types of omega-3 fatty acids, which behave differently in the body and are found in different food sources. Understanding these specific types is far more important than the semantic difference between the two terms.

What Are Omega-3 Fatty Acids?

Omega-3 fatty acids are a type of polyunsaturated fat that are essential to human health, meaning the body cannot produce them and must get them from food. The name “omega-3” is derived from their chemical structure. It refers to the location of the first double bond, which is three carbons away from the “omega,” or methyl, end of the molecular chain. This structural detail is what gives them their unique biological properties.

Omega-3s play a crucial role in many bodily functions. They are a fundamental component of the membranes that surround every cell in your body, and are particularly concentrated in the eyes, brain, and sperm cells. These healthy fats also serve as a source of energy and support the proper function of the heart, blood vessels, lungs, immune system, and endocrine system.

The Three Most Important Types of Omega-3s

While there are several types of omega-3s, the vast majority of research and health recommendations focus on three main forms: Alpha-Linolenic Acid (ALA), Eicosapentaenoic Acid (EPA), and Docosahexaenoic Acid (DHA).

ALA (Alpha-Linolenic Acid)

Source: ALA is the plant-based omega-3. It is found in foods like flaxseed, chia seeds, walnuts, and vegetable oils such as canola and soybean oil.
Function: Your body can convert ALA into the more active forms, EPA and DHA, but the conversion process is highly inefficient. Because of this, ALA intake alone is generally not sufficient to maintain optimal EPA and DHA levels, especially for those on a vegetarian or vegan diet.

EPA (Eicosapentaenoic Acid)

Source: EPA is a marine-based omega-3, found primarily in cold-water, fatty fish like salmon, mackerel, and tuna.
Function: This 20-carbon fatty acid is known for its potent anti-inflammatory properties. It produces signaling molecules called eicosanoids, which help to reduce inflammation throughout the body. Research suggests EPA may also benefit mood and mental health.

DHA (Docosahexaenoic Acid)

Source: Like EPA, DHA is a marine-based omega-3, abundant in fatty fish and algae.
Function: DHA is a 22-carbon fatty acid and is a major structural component of the brain and retina. It is critical for brain development in infants and maintains normal brain function throughout life.

Comparison Table: ALA vs. EPA vs. DHA


Feature	ALA (Alpha-Linolenic Acid)	EPA (Eicosapentaenoic Acid)	DHA (Docosahexaenoic Acid)
Source	Plants (flaxseed, walnuts, chia seeds)	Marine (oily fish, fish oil, krill oil)	Marine (oily fish, fish oil, krill oil, algae)
Function	Can be converted into EPA and DHA, though inefficiently	Anti-inflammatory effects, mood support	Major structural component of brain and retina
Carbon Atoms	18	20	22
Essential?	Yes, the body cannot make it from scratch	No, can be produced from ALA (but poorly)	No, can be produced from ALA (but poorly)

Sources of Omega-3s

To ensure a balanced intake of all types of omega-3s, it's wise to include a variety of sources in your diet. Here is a list of common foods rich in these essential fats:

Marine Sources (Rich in EPA and DHA):

Salmon
Mackerel
Sardines
Tuna
Herring
Fish oil supplements
Krill oil supplements
Algal oil (a vegetarian source of DHA and EPA)

Plant Sources (Rich in ALA):

Flaxseeds and flaxseed oil
Chia seeds
Walnuts
Soybeans
Hemp seeds
Certain leafy green vegetables

Conclusion

The fundamental takeaway is that “omega-3” and “omega-3 fatty acids” are the same thing. The distinction is not in the terminology but in the specific types of these vital nutrients—ALA, EPA, and DHA—which have different dietary sources and biological functions. For optimal health, it's important to consume sources rich in all three, particularly the marine-based EPA and DHA, which provide the most direct benefits for the heart, brain, and reducing inflammation. By focusing on the types of omega-3s rather than the wording, you can make more informed dietary choices to support your overall well-being. For more information on dietary supplements and general health recommendations, consult authoritative sources like the National Institutes of Health. NIH Office of Dietary Supplements

Frequently Asked Questions

Yes, there is no difference between the terms. “Omega-3s” is simply a shorter, more casual way of referring to “omega-3 fatty acids.”

ALA is a plant-based omega-3, while EPA and DHA are marine-based. EPA is known for its anti-inflammatory properties, and DHA is crucial for brain and eye health. The body can convert ALA into EPA and DHA, but the process is not very efficient.

You can get omega-3 fatty acids from marine sources like fatty fish (salmon, mackerel) for EPA and DHA, and from plant sources like flaxseeds, chia seeds, and walnuts for ALA.

All three types—ALA, EPA, and DHA—are important for health. However, EPA and DHA from marine sources are often considered more beneficial because they are more readily utilized by the body, as the conversion of plant-based ALA is inefficient.

Vegetarians and vegans can get ALA from plant sources but must rely on their body's inefficient conversion process for EPA and DHA. For this reason, some may consider algal oil supplements, which contain preformed EPA and DHA.

Omega-3s support heart health by reducing inflammation and promoting healthy blood vessels. They also contribute to brain development and function, vision, and immune system health.

A deficiency in omega-3s can manifest as rough, scaly skin, a red and itchy rash, and may also be associated with certain neurological symptoms and joint pain.