Omega-3s are a family of polyunsaturated fats necessary for human health. Your body cannot produce these fats in sufficient amounts, so they must be obtained through food. These fatty acids are integral to many bodily processes and are found in every cell. They are characterized by their chemical structure, which defines them as “omega-3s” and distinguishes them from other fats.
The Different Types of Omega-3s
The three primary types of omega-3s are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is a short-chain omega-3 found in plant-based foods, while EPA and DHA are long-chain omega-3s sourced from marine life. EPA is noted for its role in addressing inflammation, and DHA is a structural component of the brain and retina. The terms “short-chain” and “long-chain” refer to the number of carbon atoms in the fatty acid.
Your body can convert ALA into EPA and DHA, but this process is inefficient. The conversion involves elongating the carbon chain and adding more double bonds. Because of this limited conversion, obtaining EPA and DHA directly from dietary sources is more practical. While ALA is the most common omega-3 in the Western diet, direct consumption of EPA and DHA is often lower.
Food and Supplement Sources
Omega-3s are available in various foods and are sometimes added to fortified products. The best sources of EPA and DHA are fatty, cold-water fish. The omega-3s in fish originate from the microalgae they consume. Examples of these fish include:
- Salmon
- Mackerel
- Herring
- Sardines
- Tuna
Plant-based sources are rich in ALA. Flaxseeds, chia seeds, and walnuts are excellent sources. Plant oils such as flaxseed oil, soybean oil, and canola oil also contain ALA. Other plant-based options include edamame and various soy products.
Omega-3 supplements are available for those who do not consume fish. Fish oil is a common supplement providing both EPA and DHA. For individuals following a vegan or vegetarian diet, algal oil is a plant-based supplement that provides both EPA and DHA. Krill oil is another marine-based option.
The Role of Omega-3 in the Body
Omega-3 fatty acids are integral to the function of cells throughout the body. They are a component of cell membranes, helping to maintain their structure and facilitate communication between cells. Omega-3s also provide the body with calories for energy.
Omega-3s play a role in the cardiovascular system by helping to lower triglyceride levels in the blood. High triglycerides are a risk factor for atherosclerosis, which can lead to heart disease and stroke. Omega-3s can also help lower blood pressure and may reduce the risk of blood clots.
Beyond heart health, omega-3s are involved in the body’s inflammatory response. They can be converted into signaling molecules called eicosanoids. This anti-inflammatory property is beneficial for conditions involving chronic inflammation.
Recommended Intake and Deficiency Signs
Health organizations provide recommendations for daily omega-3 intake, though specific needs can vary. The National Academy of Medicine suggests a daily ALA intake of 1.6 grams for adult men and 1.1 grams for adult women. For EPA and DHA combined, some health bodies advise 200-500 milligrams per day for healthy adults, which can be met by eating fatty fish once or twice a week.
An omega-3 deficiency is uncommon in the United States but can lead to noticeable symptoms. A common sign is skin irritation, such as dry, scaly skin or a red, itchy rash. Changes in hair, such as brittleness, can also occur.
Other signs of low omega-3 levels relate to neurological and cognitive function, including difficulty concentrating or feelings of fatigue. Since these symptoms are associated with many conditions, consider your dietary intake of omega-3-rich foods if you experience them.