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.

By Mayo Clinic Staff

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 with 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:

  • Salmon
  • Sardine
  • Atlantic mackerel
  • Cod
  • Herring
  • 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.

In order 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 is 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 the 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:

  • Shark
  • Tilefish
  • Swordfish
  • King mackerel

Are there any other concerns related to eating fish?

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 does using supplements. If you don't want or like fish, other things that have some omega-3 fatty acids are:

  • Flaxseed and flaxseed oil
  • Walnuts
  • 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 doesn't seem to be as strong as it is from eating fish.

From Mayo Clinic to your inbox

Sign up for free, and stay up to date on research advancements, health tips and current health topics, like COVID-19, plus expertise on managing health.

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 set forth 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.

April 19, 2022 See more In-depth

See also

  1. Air pollution and exercise
  2. Angina
  3. Atkins Diet
  4. Automated external defibrillators: Do you need an AED?
  5. Blood Basics
  6. Blood tests for heart disease
  7. Bradycardia
  8. Screenings of newborns and athletes for genetic heart disease
  9. Transplant Advances
  10. Butter vs. margarine
  11. Calcium supplements: A risk factor for heart attack?
  12. Can vitamins help prevent a heart attack?
  13. Cardiac ablation
  14. Infographic: Cardiac Ablation
  15. Cardiac amyloidosis — Treatment options
  16. Cardiac amyloidosis — What is amyloid and how does it affect the heart
  17. Cardiac catheterization
  18. Cardioversion
  19. Chelation therapy for heart disease: Does it work?
  20. Chest X-rays
  21. Complete blood count (CBC)
  22. Coronary angiogram
  23. Coronary angioplasty and stents
  24. Coronary artery spasm: Cause for concern?
  25. Coronary bypass surgery
  26. Cough
  27. CT scan
  28. Daily aspirin therapy
  29. Dizziness
  30. Don't get tricked by these 3 heart-health myths
  31. Echocardiogram
  32. Ejection fraction: What does it measure?
  33. Electrocardiogram (ECG or EKG)
  34. Heart transplant to treat dilated cardiomyopathy: Elmo's story
  35. Erectile dysfunction: A sign of heart disease?
  36. Exercise and chronic disease
  37. Fasting diet: Can it improve my heart health?
  38. Fatigue
  39. Flu Shot Prevents Heart Attack
  40. Flu shots and heart disease
  41. Foot swelling during air travel: A concern?
  42. Grass-fed beef
  43. Hand swelling during exercise: A concern?
  44. Healthy eating: One step at a time
  45. Healthy Heart for Life!
  46. Heart arrhythmia
  47. Heart attack
  48. Heart attack prevention: Should I avoid secondhand smoke?
  49. Heart attack symptoms
  50. Heart Attack Timing
  51. Heart disease
  52. Heart disease in women: Understand symptoms and risk factors
  53. Heart disease and oral health
  54. Heart-healthy diet: 8 steps to prevent heart disease
  55. Heart murmurs
  56. Heart transplant
  57. Herbal supplements and heart drugs
  58. Holter monitor
  59. Honey: An effective cough remedy?
  60. Implantable cardioverter-defibrillators (ICDs)
  61. Leg swelling
  62. Limit bad fats, one step at a time
  63. Mediterranean diet
  64. Mediterranean diet recipes
  65. Menus for heart-healthy eating
  66. MUFAs
  67. Need a snack? Go nuts!
  68. NSAIDs: Do they increase my risk of heart attack and stroke?
  69. Nuclear stress test
  70. Numbness
  71. Nuts and your heart: Eating nuts for heart health
  72. Omega-6 fatty acids
  73. Infographic: Organ Donation Donate Life
  74. Organ transplant in highly sensitized patients
  75. Pacemaker
  76. Pericardial effusion
  77. Polypill: Does it treat heart disease?
  78. Protein: Heart-healthy sources
  79. Pseudoaneurysm: What causes it?
  80. Pulmonary edema
  81. Put fish on the menu
  82. Red wine, antioxidants and resveratrol
  83. Shortness of breath
  84. Silent heart attack
  85. Sitting risks: How harmful is too much sitting?
  86. Mediterranean diet
  87. Vegetable recipes
  88. Guide to gourmet salt
  89. Heart disease prevention
  90. Stress symptoms
  91. Stress test
  92. Tachycardia
  93. The Last Brother's Heart
  94. Integrative approaches to treating pain
  95. Nutrition and pain
  96. Pain rehabilitation
  97. Self-care approaches to treating pain
  98. Trans fat
  99. Triathlete Transplant
  100. Coronary angioplasty
  101. Video: Heart and circulatory system
  102. What is meant by the term "heart age"?
  103. Whole grains for a healthy heart
  104. Infographic: Women and Heart Disease