If you're looking to boost your heart health, improve brain function, or reduce inflammation, fish oil might be just what you need. Found in fatty fish like salmon, mackerel, and tuna, fish oil is packed with omega-3 fatty acids—specifically docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)—that are linked to numerous health benefits. Since your body can't produce these essential fats on its own, obtaining them through diet is crucial. Unless you're eating fatty fish regularly or taking an omega-3 supplement, you might not get enough, which could negatively affect your health. But what exactly is fish oil, and how much do you need to reap its benefits?
Extensive research, including more than 4,500 human clinical trials, highlights the benefits of DHA and EPA for pregnancy, brain function, eye health, and heart health. Omega-3s are known to reduce inflammation, improve mood, and support the immune system. According to the National Institutes of Health, these beneficial fats are vital components of cell membranes, particularly in the brain, eyes, and sperm cells, and play key roles in heart and immune health.
In this article, we'll explore what fish oil is, its nutrition profile, the positive and negative side effects, and how to incorporate it into your diet, with insights from a registered dietitian.
What Are Fish Oil Supplements?
DHA and EPA, two key omega-3 fatty acids, originate from algae, which fish consume and store in their fatty tissues. As a result, fatty fish like salmon, mackerel, sardines, and anchovies are some of the best natural sources of omega-3s. Some fish, like cod and pollock, contain significantly lower amounts, so consuming fatty fish is the most effective way to boost DHA and EPA levels. For optimal health, the American Heart Association recommends at least two servings (3 ounces each) of fatty fish per week.
While the body can convert a small amount of the plant-based omega-3 alpha-linolenic acid (ALA) into DHA and EPA, the conversion is inefficient—making fatty fish or fish oil supplements the most reliable sources of these beneficial fats.
Fish oil supplements are made by extracting oil from the tissues of oily fish, which is then purified to remove contaminants like mercury and concentrated to boost DHA and EPA levels. Available in liquids, capsules, and soft gels, these supplements offer a convenient way to get essential omega-3s if your diet is lacking in fatty fish.
Fish Oil Nutrition Facts
Fish oil supplements come in various forms, including capsules and liquids. A typical capsule contains around 15-25 calories and 2-3 grams of fat, with at least 500 milligrams of EPA and DHA combined. Liquid forms may provide more than 1,500 milligrams of EPA and DHA per teaspoon, with about 40 calories and 5 grams of fat per serving. Many fish oil supplements also contain vitamin E to prevent oxidation.
Fish Oil Benefits
Heart Health Support
The American Heart Association states that EPA and DHA can help lower triglycerides linked to heart disease. Research from The Journal of the American Heart Association shows omega-3s can reduce triglycerides by 15-30%, especially at doses above 2 grams daily. Those at higher risk of cardiovascular disease, including individuals with obesity or high cholesterol, may experience even greater benefits.
Eye Health Support
DHA is highly concentrated in the retina and plays a key role in maintaining eye health throughout life. Low intake of omega-3s has been linked to a higher risk of retinopathy. A study in Antioxidants suggests that DHA has anti-inflammatory, antioxidant, and protective effects in the retina.
Reduced Heart Attack Risk
Research published in Mayo Clinic Proceedings found that omega-3s significantly reduce the risk of heart attacks and coronary heart disease deaths. Even relatively low doses—500 milligrams per day—may provide protective benefits. However, individuals with heart disease risk factors should consult a healthcare professional before starting fish oil supplements.
Skin Health Support
EPA and DHA may also benefit skin health, offering protection against UV damage, reducing the risk of skin cancer, and aiding in wound healing. A review in Marine Drugs found that fish oil's anti-inflammatory properties help protect skin cells, and some studies suggest it may speed up wound closure, although more research is needed.
Omega-3s and Pregnancy
Omega-3s are particularly important during pregnancy. EPA and DHA support the development of the baby's brain and retina. A Cochrane Library review analyzed 70 trials and concluded that omega-3 supplementation during pregnancy reduces the risk of preterm birth, low birth weight, and early preterm birth with minimal risk.
A study in Annals of Nutrition & Metabolism also notes that omega-3s support cognitive, motor, and visual development and may reduce the incidence of atopic eczema in children. Pregnant women should consult their healthcare providers about increasing omega-3 intake for maternal and fetal health benefits.
Potential Drawbacks of Fish Oil
Gastrointestinal Issues
While fish oil is generally well-tolerated, some people experience fishy aftertaste, heartburn, or indigestion. If you're taking fish oil for a specific health reason, consult your healthcare provider and follow dosage instructions carefully.
A-Fib Concerns
Some research suggests that EPA and DHA may be associated with atrial fibrillation (also known as A-fib), according to a review article published in Circulation. For most individuals, the heart health benefits of fish oil exceed the potential risk for A-fib, but everyone should always check with their healthcare professional before taking any supplements.
Recent studies have questioned the benefits of EPA/DHA omega-3 supplementation due to its potential connection with A-fib. While there appears to be a dose-dependent association between EPA/DHA supplementation and risk for A-fib, there are still concerns and unanswered questions about the strength of the association.
How Much Omega-3 Is Enough?
There is no established dietary reference intake for EPA and DHA in the U.S. for those over 1 year old. However, experts recommend at least 500 milligrams per day for healthy adults, with pregnant and lactating women needing at least 700 milligrams, including 300 milligrams of DHA.
Final Thoughts and Recommendations
If you don't eat fatty fish at least twice a week, I recommend speaking to your healthcare professional about the pros and cons of taking a fish oil supplement. You and your healthcare professional can decide if fish oil is right for you, depending on your health goals and personalized health concerns. So many options are on the market, including capsules, liquids, or algae-derived supplements that will provide beneficial EPA and DHA to your diet.