Originally posted 2017 / Updated April 2025
What Are Omega-3 Fatty Acids?
Omega-3 fatty acidsare a type of polyunsaturated fat that play a crucial role in cellular function, heart and mental health, and reducing inflammation. There are two main types of omega-3s: short-chain and long-chain.
Omega-3 fatty acids include short-chain alpha-linolenic acid (ALA) and long-chain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Long-chain omega-3s play a key role in cell membrane health, reducing inflammation, supporting heart health, and preventing chronic diseases like diabetes, arthritis, and cancer.
Food Sources Of Omega-3 Fatty Acids
ALA, the short-chain omega-3, is found in plant sources like flaxseeds and flaxseed oil, chia seeds, walnuts, and soybeans.
The long-chain omega-3 fatty acids EPA, DHA, and others are found in fatty fish such as salmon, mackerel, and sardines and infish oil,krill oil, andalgae oildietary supplements.
While most Americans eat way too much of the omega-6 fatty acids found in meat, dairy, and most seed oils, they suffer a relative deficiency of the omega-3 fatty acids, especially for EPA and DHA. Several studies have shown that vegetarians and vegans, even with a high intake of ALA, have much lower blood levels of DHA and EPA when compared to those who eat fish or take fish oil supplements.
Health Benefits Of Omega-3 Fatty Acids
Consuming omega-3s, especially the long-chain forms, is linked to various health benefits, including improved heart health, reduced risk of chronic diseases, better brain function, and reduced inflammation. Here are the top ten health benefits of omega-3 supplements.
The benefits of long-chain omega-3 fatty acid supplementation for cardiovascular health have been demonstrated in more than 300 clinical trials. These omega-3 fatty acids exert a myriad of beneficial effects, including improving blood cholesterol and triglyceride levels, improving the function of the lining of blood vessels and the flexibility of blood vessels, improving blood and oxygen supply to the heart, and producing a mild effect in lowering blood pressure.
The long-chain omega-3 fatty acids also protect against excessive adhesiveness or “stickiness” of platelets. While saturated fats and oxidized cholesterol increase platelet aggregation, EPA and DHA and the monounsaturated fats from olive oil, nuts, and seeds have the opposite effect. The beneficial effects of fish oils on platelet aggregation may be one of the key reasons why higher levels of EPA and DHA in the diet and blood are associated with a reduced risk of stroke or heart attack.
Fish oil supplementation has been shown to lower levels of C-reactive protein, a marker of chronic inflammation linked to a higher risk for heart disease. Chronic inflammation is linked not only to heart disease but also to aging and chronic degenerative issues like poor blood sugar control, obesity, diabetes, and poor joint health. EPA+DHA supplementation has been shown to significantly reduce various blood markers indicative of inflammation. The most consistent finding related to the mechanisms of action is a reduction in the production of inflammatory mediators known as cytokines produced by white blood cells. The most consistent marker reduced is C-reactive protein.
Another major benefit of fish oil is its positive impact on brain function, mood, and mental health. DHA, a major structural component of brain cells, plays an essential role in brain health from fetal and infant brain development to cognitive health throughout the human lifespan. However, while preformed DHA is the primary source of DHA in the brain of infants, almost all the DHA in the developed brain is made from EPA. Both EPA and DHA improve neurotransmitter function, particularly serotonin and dopamine, which regulate mood and emotional stability. EPA and DHA are especially helpful in supporting the connection and communication between brain cells, which is crucial for memory and learning. Studies have shown that fish oil supplementation may help reduce symptoms of depression, anxiety, stress, and ADHD and improve mental function.
DHA and EPA play a crucial role in maintaining eye health and reducing the risk of various eye-related conditions. In children, adequate DHA intake is essential for proper visual development. DHA is a major structural component of the retina, the light-sensitive layer at the back of the eye responsible for transmitting visual signals to the brain. Studies indicate that infants who receive sufficient DHA during pregnancy and early childhood have improved visual acuity and overall eye function. Pregnant and breastfeeding mothers are often encouraged to take fish oil supplements to support their baby’s eye and brain development.
Since the retina contains a high concentration of DHA, a sufficient intake of this omega-3 is essential for preserving optimal vision and preventing degenerative eye diseases, including age-related macular degeneration (AMD) and diabetic retinopathy, which are leading causes of vision loss in older adults.
Fish oil supplementation can also help glaucoma and dry eye syndrome. EPA and DHA can help improve eye pressure, enhance tear production, and reduce eye irritation and swelling associated with chronic dry eye conditions.
EPA and DHA improve metabolism in a number of ways. For example, they help increase the breakdown of stored fat into fatty acids, making them available for energy production. They also can enhance mitochondrial function, allowing cells to burn fat more efficiently for energy instead of storing it. Some of the other benefits for metabolic health and weight management include increasing the sensitivity of cells to insulin. When cells are resistant to insulin, it leads to increased blood sugar levels and fat storage, as well as loss of appetite control. EPA and DHA also influence key hormones involved in appetite control to promote satiety. Finally, omega-3 fatty acids promote a healthier microbiome linked to better metabolic health and lower obesity risk.
In addition to being necessary for proper development of the fetal brain and eyes, omega-3 fatty acids are also critical to the development of the fetal immune system. EPA and DHA also reduce the risk of premature birth, as studies show that pregnant women who consume higher levels of these long-chain omega-3s have lower chances of delivering before 37 weeks. This benefit is important as preterm birth is associated with a higher risk of complications like underdeveloped lungs, low birth weight, and neurodevelopmental delays. Babies born to mothers with sufficient omega-3 intake have better birth weight, fat distribution, and metabolic health.
There are also many benefits for the mother. The most well-documented benefit is lowering the risk of postpartum depression. But, long-chain omega-3s may also help the mother to reduce her risk of high blood pressure and gestational diabetes.
Long-chain omega-3 fatty acids play a significant role in supporting the skin’s basic barrier function by helping it maintain the skin’s barrier function, thereby reducing dryness and keeping the skin hydrated. Their anti-inflammatory properties can help reduce skin redness and irritation, as well as promote wound healing. EPA and DHA may also support collagen production, helping to maintain skin elasticity and prevent wrinkle formation.
EPA and DHA promote joint health primarily through reducing the production of inflammatory compounds that can lead to pain and stiffness thereby improving comfort, mobility, range of motion, and overall joint function.
Bone health is also improved; higher levels of long-chain omega-3s are associated with higher bone mineral density, improved bone strength, and reduced risk of fractures in older adults.
The International Society of Sports Nutrition (ISSN), after a critical examination of the research surrounding the effects of long-chain omega-3 polyunsaturated fatty acid supplementation, concluded the following:
Athletes are at risk for a deficiency of EPA and DHA.Supplementation with EPA+DHA to athletes has been shown to enhance endurance capacity and cardiovascular function during aerobic-type exercise.EPA+DHA supplementation in combination with resistance training may improve strength in athletes involved in a strength-training program.EPA+DHA supplementation may decrease subjective measures of muscle soreness following intense exercise.EPA+DHA supplementation can positively affect various immune cell responses in athletes.EPA+DHA supplementation may offer protection to the brain in athletes exposed to repeated head impacts.EPA+DHA supplementation is associated with improved sleep quality.
Athletes are at risk for a deficiency of EPA and DHA.
Supplementation with EPA+DHA to athletes has been shown to enhance endurance capacity and cardiovascular function during aerobic-type exercise.
EPA+DHA supplementation in combination with resistance training may improve strength in athletes involved in a strength-training program.
EPA+DHA supplementation may decrease subjective measures of muscle soreness following intense exercise.
EPA+DHA supplementation can positively affect various immune cell responses in athletes.
EPA+DHA supplementation may offer protection to the brain in athletes exposed to repeated head impacts.
EPA+DHA supplementation is associated with improved sleep quality.
It was alarming to researchers to find that in a 2019 study of 404 collegiate football players, not a single athlete had an omega-3 index above 4%, indicating a significant deficiency of the long-chain omega-3 fatty acids. To raise the omega-3 index to the target value of 8%, the ISSN researchers recommend an additional daily intake of about 1.4 g of EPA+DHA.
Long-chain omega-3 fatty acids support various aspects of women’s health throughout different life stages. In addition to supporting all the functions discussed above pertaining to women’s health, EPA and DHA are very important in many other benefits with EPA+DHA in women. Here are just a few examples:
Reduce Menstrual Cramps: a meta-analysis of eight double-blind human studies showed EPA+DHA supplementation (300 to 1,800 mg a day) over 2-3 months produces a significant impact in helping to reduce menstrual cramps.Reduce PMS Symptoms: EPA and DHA may help in reducing the mood swings, fluid retention, and feelings of bloating associated with PMS.Reduces Menopausal Hot Flashes: EPA+DHA supplementation combined with a lacto-ovo-vegetarian diet improved hot flashes in menopausal women.
Reduce Menstrual Cramps: a meta-analysis of eight double-blind human studies showed EPA+DHA supplementation (300 to 1,800 mg a day) over 2-3 months produces a significant impact in helping to reduce menstrual cramps.
Reduce PMS Symptoms: EPA and DHA may help in reducing the mood swings, fluid retention, and feelings of bloating associated with PMS.
Reduces Menopausal Hot Flashes: EPA+DHA supplementation combined with a lacto-ovo-vegetarian diet improved hot flashes in menopausal women.
Should You Supplement With Omega-3s?
To boost EPA and DHA most effectively, dietary supplementation is recommended by many health experts. Supplementation has an advantage over dietary intake. While many studies indicate that fish consumption offers significant health promotion and protection against many chronic diseases due to their long-chain omega-3 fatty acid levels, nearly all fish contain trace amounts of mercury and other toxic compounds. In most cases, the toxin content in fish is of little concern because the level is so low, but if you are eating a lot of fish, it could pose a problem.
In contrast, a high-quality fish, krill, or algae oil provides a high content of EPA and/or DHA without the concern of mercury, PCBs, dioxins, and other contaminants often found in whole fish. In general, those products that provide a minimum of 60% omega-3 fatty acid content provide a good indication of quality. Whether the form is a triglyceride or ethyl-ester or comes from krill oil, wild salmon oil, and other marine lipids, the key is supplying the recommended levels of 1,000 to 2,000 mg EPA+DHA (combined total). While some algae sources provide only DHA and not EPA, DHA alone is not as beneficial, especially in promoting proper brain development and mood health.
Supplement Quality Matters
The development of high-quality dietary supplements providing long-chain omega-3 fatty acids has been one of the most important advances in nutritional approaches to improving health. Whether the source is fish, krill, or algae, there are someimportant guidelines to consider:
Concentration: Look for higher concentrations of EPA and/or DHA for higher-quality products (e.g., >60% total omega-3 fatty content).Look for Sustainable Fish Sources: Small, cold-water fish like anchovies, sardines, or mackerel are lower in contaminants than larger fish.Third-party Testing. Look for independent lab testing (e.g., IFOS, USP, NSF, iTested, or GOED certification) to ensure purity and potency.Dosage Considerations: Remember it is the total dosage of EPA and/or DHA that is important, not the total amount of fish oil. The dosage recommendation is 1,000 to 2,000 mg of EPA and/or DHA daily.
Concentration: Look for higher concentrations of EPA and/or DHA for higher-quality products (e.g., >60% total omega-3 fatty content).
Look for Sustainable Fish Sources: Small, cold-water fish like anchovies, sardines, or mackerel are lower in contaminants than larger fish.
Third-party Testing. Look for independent lab testing (e.g., IFOS, USP, NSF, iTested, or GOED certification) to ensure purity and potency.
Dosage Considerations: Remember it is the total dosage of EPA and/or DHA that is important, not the total amount of fish oil. The dosage recommendation is 1,000 to 2,000 mg of EPA and/or DHA daily.
