Foods as sources of omega-3: Where are they most abundant?

Omega-3 fatty acids have been one of the most debated topics in nutrition and health in recent years. They are presented as the key to promoting heart health, brain health and overall vitality. What exactly are these "miracle" fats? Why does our body absolutely need them and which foods are their richest sources? In this, our new article, we provide a detailed and science-based overview to help you navigate the world of omega-3s and make informed decisions for your health.

Article Content:

• What are omega-3s and why are they "essential"?
• The Two Worlds of Omega-3: Plant vs. Animal Sources
• Health benefits backed by science
• Are there any risks? Quality over quantity

What are omega-3s and why are they "essential"?

Omega-3 fatty acids belong to a group of polyunsaturated fats that are absolutely indispensable to the human body. The term "essential" means that our body cannot produce them on its own and we must take them from our diet. They act as the building blocks of cell membranes throughout the body and influence the function of cell receptors. They play a key role in the production of hormones that regulate blood clotting, artery wall contraction and relaxation, and inflammatory processes in the body^.1

There are three main types of omega-3 fatty acids that are most important for our health:

1. Alpha-linolenic acid (ALA): this is the most common omega-3 fatty acid in the Western diet, found primarily in plant sources. The body uses it mainly as an energy source.
2. Eicosapentaenoic acid (EPA): This acid is found primarily in seafood. Its main function is to produce chemicals called eicosanoids, which help reduce inflammation. EPA is also known for its positive effect on mental health.
3. Docosahexaenoic acid (DHA): DHA is a key structural component of the cerebral cortex, the retina and many other parts of the body. It is essential for the development of the brain during the prenatal period and early childhood and for maintaining proper brain function in adulthood^.3

The human body can convert ALA to the more functionally important EPA and DHA to a limited extent. However, this process is very inefficient. Scientific studies indicate that only a small percentage of ingested ALA (often less than 5%) is converted to EPA and even less to DHA^.2 Therefore, to ensure adequate amounts of these key fatty acids, it is essential to focus on sources that contain them directly.

The Two Worlds of Omega-3: Plant vs. Animal Sources

Sources of omega-3 can be divided into two main categories, which differ in the type of acids they provide.

Plant sources and their champion ALA

The plant kingdom is the primary source of alpha-linolenic acid (ALA). Although the conversion rate to EPA and DHA is low, these foods are an extremely valuable part of a healthy diet due to their fiber, vitamin and mineral content.

• Flaxseed and flaxseed oil: They are the absolute king among plant sources. One tablespoon (about 15 ml) of flaxseed oil contains approximately 7.3 grams of ALA, far exceeding the daily recommended intake^.1
• Chia seeds: another superfood that packs approximately 5 grams of ALA into 28 grams (about 2 tablespoons).
• Walnuts: are the best nut source of omega-3s. A 28-gram serving (approximately 7 whole nuts) provides about 2.6 grams of ALA.
• Canola and soybean oil: These commonly used oils are also good sources of ALA and can contribute to your total daily intake.

Marine sources: a direct route to EPA and DHA

For a direct supply of the most biologically active forms of omega-3 - EPA and DHA - it is essential to turn to the gifts of the sea. These acids accumulate in the tissues of fatty marine fish, which feed on phytoplankton and the microalgae that produce them.

• Salmon: Wild and farmed salmon is one of the best known and richest sources. A 100 gram serving can contain 1.5-2.5 grams of EPA and DHA combined.
• Mackerel: This smaller but nutritionally very rich fish provides over 2.5 grams of EPA and DHA in a 100 gram serving.
• Sardines: Eating sardines, often in canned form, is an easy and affordable way to get omega-3s. One can (about 100 grams) can contain up to 1.5 grams of EPA and DHA.
• Herring (Herring): Another fatty fish that is particularly popular in northern Europe, offering almost 2 grams of EPA and DHA per 100 grams.
• Fish oil and krill oil: Concentrated dietary supplements that are an effective way to ensure a high intake of EPA and DHA, especially for people who do not consume fish regularly.

Health benefits backed by science

Extensive research has confirmed the many positive effects of omega-3 fatty acids on human health.

• Heart and vascular health: EPA and DHA help to lower blood pressure, blood triglyceride levels and slow the development of plaque in the arteries. This significantly reduces the risk of heart attack and stroke^.3
• Brain function and mental health: DHA is essential for a healthy brain. Adequate intake is associated with better cognitive performance, reduced risk of dementia in old age and may help alleviate symptoms of depression and anxiety.
• Suppressing inflammation: chronic inflammation is at the root of many diseases of civilization. Omega-3s, especially EPA, have powerful anti-inflammatory effects that may help with diseases such as rheumatoid arthritis.
• Eye health: DHA is a major structural component of the retina. Its deficiency can lead to vision problems and is associated with a higher risk of macular degeneration^.1

Are there any risks? Quality over quantity

Concerns about the content of heavy metals such as mercury are sometimes raised when eating fish. Most scientific studies agree that the health benefits of eating fish far outweigh the potential risks^.4 In general, smaller fish such as sardines, anchovies and herring contain fewer contaminants than large predatory fish (e.g. shark, swordfish).

For those who want to avoid these risks altogether or do not consume enough fish, high-quality fish oil supplements are a safe and effective alternative. These products are purified (by molecular distillation) to remove any potential contaminants while ensuring high concentrations and stability of EPA and DHA.

Conclusion

Omega-3 fatty acids are an indispensable part of our diet with a profound impact on our overall health. The key to success is understanding the difference between the different types and their sources. While plant foods such as flaxseed and walnuts are great sources of essential ALA, fatty marine fish remains the best choice for ensuring sufficient amounts of the most biologically potent components - EPA and DHA. By choosing your foods carefully and supplementing your diet with quality supplements where appropriate, you can actively support your heart and brain health and protect your body from chronic inflammation.

Sources:

• 1: National Institutes of Health (2023). Omega-3 Fatty Acids - Health Professional Fact Sheet. ODS.OD.NIH.GOV.
• 2: Brenna, J. T. (2009). Omega-3 fatty acids: comparison of plant and seafood sources in human nutrition. PubMed.
• 3: Cleveland Clinic.(2022) Staying Healthy with Omega-3 Fatty Acids. NCBI.
• 4: Mozaffarian, D., & Rimm, E.. B. (2006). Dietary Sources of Omega-3 Fatty Acids: Public Health Risks and Benefits. PubMed.