Omega-3 in fish: How eating fish helps your heart
The omega-3 fatty acids in fish are good for the heart. Find out why the heart-healthy benefits of eating fish usually outweigh any risks.
If you’re worried about your heart health, eating at least two servings of fish a week could reduce the risk of heart disease.
For many years, the American Heart Association has recommended that people eat fish rich in unsaturated fats at least twice a week. The unsaturated fats in fish are called omega-3 fatty acids. Omega-3 fatty acids and other nutrients in fish may benefit heart health and reduce the risk of dying of heart disease.
Some people are concerned about mercury or other contaminants in seafood. However, the benefits of eating fish as part of a healthy diet usually outweigh the possible risks of exposure to contaminants. Learn how to balance these concerns by adding a healthy amount of fish to your diet.
What are omega-3 fatty acids, and why are they good for your heart?
Omega-3 fatty acids are a type of unsaturated fatty acid that may reduce inflammation throughout the body. Inflammation in the body can damage the blood vessels and lead to heart disease and strokes.
Omega-3 fatty acids may benefit heart health by:
- Decreasing triglycerides
- Lowering blood pressure slightly
- Reducing blood clotting
- Decreasing the risk of strokes and heart failure
- Reducing irregular heartbeats
Try to eat at least two servings a week of fish, particularly fish that’s rich in omega-3 fatty acids. Doing so appears to reduce the risk of heart disease, particularly sudden cardiac death.
Does it matter what kind of fish you eat?
Many types of seafood contain small amounts of omega-3 fatty acids. Fatty fish contain the most omega-3 fatty acids and seem to be the most beneficial to heart health.
Good omega-3-rich fish options include:
- Atlantic mackerel
- Lake trout
- Canned, light tuna
How much fish should you eat?
The U.S. Food and Drug Administration (FDA) recommends fish as part of a healthy diet for most people. But some groups should limit the amount of fish they eat.
Most adults should eat at least 8 ounces or two servings of omega-3-rich fish a week. A serving size is 4 ounces or about the size of a deck of cards.
If you’re pregnant, planning to become pregnant, or are breastfeeding, you can still get the heart-healthy benefits of fish from a variety of seafood and fish that are typically low in mercury, such as salmon and shrimp. Limit the amount you eat to:
- No more than 12 ounces (340 grams) of fish and seafood in total a week
- No more than 4 ounces (113 grams) of albacore tuna a week
- No amount of any fish that’s typically high in mercury (shark, swordfish, king mackerel, and tilefish)
Young children also should avoid fish with potentially high levels of mercury contamination. Kids should eat fish from choices lower in mercury once or twice a week. The serving size for children younger than age 2 is 1 ounce and increases with age.
To get the most health benefits from eating fish, pay attention to how it’s cooked. For example, grilling, broiling, or baking fish is a healthier option than deep-frying.
Does mercury contamination outweigh the health benefits of eating fish?
If you eat a lot of fish containing mercury, the toxin can build up in the body. It’s unlikely that mercury would cause any health concerns for most adults. But it is particularly harmful to the development of the brain and nervous system of unborn children and young children.
For most adults, the benefits of omega-3 fatty acids outweigh the risk of getting too much mercury or other contaminants. The main toxins in fish are mercury, dioxins, and polychlorinated biphenyls (PCBs). The amount of toxins depends on the type of fish and where it’s caught.
Mercury occurs naturally in small amounts in the environment. But industrial pollution can produce mercury that collects in lakes, rivers, and oceans. That pollution can end up in the food that fish eat. When fish eat this food, mercury builds up in their bodies of the fish.
Large fish that are higher in the food chain eat the smaller fish, gaining higher concentrations of mercury. The longer a fish lives, the larger it grows and the more mercury it can collect. Fish that may contain higher levels of mercury include:
- King mackerel
Some studies say high levels of omega-3 fatty acids in the blood increase the risk of prostate cancer. But other studies say they might prevent prostate cancer.
None of these studies were conclusive. More research is needed. Talk with your health care provider about what this potential risk might mean to you.
Some researchers are also concerned about eating fish produced on farms as opposed to wild-caught fish. Antibiotics, pesticides, and other chemicals may be used in raising farmed fish. However, the FDA has found that the levels of contaminants in commercial fish don’t seem to be bad for health.
Can you get the same heart-healthy benefits by eating other foods that contain omega-3 fatty acids, or by taking omega-3 fatty acid supplements?
Eating fish rich in omega-3 fatty acids and other nutrients seems to provide more heart-healthy benefits than using supplements. If you don’t want or like fish, other things that have some omega-3 fatty acids are:
- Flaxseed and flaxseed oil
- Canola oil
- Soybeans and soybean oil
- Chia seeds
- Green leafy vegetables
- Cereals, pasta, dairy, and other food products fortified with omega-3 fatty acids
As with supplements, the heart-healthy benefits from eating these foods don’t seem to be as strong as it is from eating fish.
Get the latest health information from Mayo Clinic’s experts.
Sign up for free, and stay up to date on research advancements, health tips, and current health topics, like COVID-19, plus expertise in managing health.
Learn more about Mayo Clinic’s use of data. To provide you with the most relevant and helpful information, and understand which
information is beneficial, we may combine your email and website usage information with
other information we have about you. If you are a Mayo Clinic patient, this could
include protected health information. If we combine this information with your protected
health information, we will treat all of that information as protected health
information and will only use or disclose that information as outlined in our notice of
privacy practices. You may opt out of email communications at any time by clicking on
the unsubscribe link in the e-mail.
Subscribe! Show references
- Fish and omega-3 fatty acids. American Heart Association. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/fish-and-omega-3-fatty-acids. Accessed March 25, 2022.
- Mozaffarian D. Fish oil: Physiologic effects and administration. https://www.uptodate.com/contents/search. Accessed March 25, 2022.
- Khan SU, et al. Effect of omega-3 fatty acids on cardiovascular outcomes: A systematic review and meta-analysis. Clinical Medicine. 2021; doi:10.1016/j.eclinm.2021.100997.
- Goel A, et al. Fish, fish oils and cardioprotection: Promise or fish tale? International Journal of Molecular Sciences. 2018; doi:10.3390/ijms19123703.
- Advice about eating fish. U.S. Food and Drug Administration. https://www.fda.gov/food/consumers/advice-about-eating-fish. Accessed March 25, 2022.
- Bowen KJ, et al. Omega-3 fatty acids and cardiovascular disease: Are there benefits? Current Treatment Options in Cardiovascular Medicine. 2016; doi:10.1007/s11936-016-0487-1.
- Abdelhamid AS, et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews. 2020; doi:10.1002/14651858.CD003177.pub5.
- Willet W, et al. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. The Lancet Commissions. 2019; DOI: 10.1016/S0140-6736(18)31788-4.
- Del Gobbo LC, et al. Omega-3 polyunsaturated fatty acid biomarkers and coronary heart disease. JAMA Internal Medicine. 2016; DOI: 10.1001/jamainternmed.2016.2925.
- Siscovick DS, et al. Omega-3 polyunsaturated fatty acid (fish oil) supplementation and the prevention of clinical cardiovascular disease. Circulation. 2017; doi:10.1161/CIR.0000000000000482.
- Oken E. Fish consumption and marine omega-3 fatty acid supplementation in pregnancy. https://www.uptodate.com/contents/search. Accessed March 25, 2022.
- Questions & answers from the FDA/EPA Advice about eating fish for those who might become or are pregnant or breastfeeding and children ages 1 to 11 years. U.S. Food and Drug Administration. https://www.fda.gov/food/consumers/questions-answers-fdaepa-advice-about-eating-fish-those-who-might-become-or-are-pregnant-or. Accessed March 25, 2022.
- Saavedra S, et al. Impact of dietary mercury intake during pregnancy on the health of neonates and children: A systematic review. Nutrition Reviews. 2022; doi:10.1093/nutrient/nuab029.
- Wang Y, et al. Dietary fish, and omega-3 polyunsaturated fatty acids intake and cancer survival: A systematic review and meta-analysis. Critical Reviews in Food Science and Nutrition. 2022; doi:10.1080/10408398.2022.2029826.