Omega 3 Fatty Acids - The Power of Fish | Cleveland Clinic

The Power of Fish

What are omega-3 fatty acids?

Omega-3 fatty acids are a type of fat the body cannot make on its own. They are an essential fat, which means they are needed to survive. We get the omega-3 fatty acids we need from the foods we eat.

What are the best sources of omega-3 fatty acids?

Fish are the best food source of omega-3 fatty acids. Some plants also contain omega-3 fatty acids.

What do EPA, DHA and ALA mean?

There are two kinds of omega-3 fatty acids in fish — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The form of omega-3 in plants is called alpha-linolenic (ALA).

How do omega-3 Fatty Acids help improve my health?

Research shows that omega-3 fatty acids can improve your cardiovascular health. Most of this research involves EPA + DHA, but ALA can also help improve your health. Benefits of including omega-3 fatty acids in your diet include:

  • Reduced risk of cardiovascular disease.
  • Reduced risk of death if you have cardiovascular disease.
  • Reduced risk of sudden cardiac death caused by an abnormal heart rhythm.
  • Reduced risk of blood clots because omega-3 fatty acids help prevent blood platelets from clumping together.
  • Keeping the lining of the arteries smooth and free of damage that can lead to thick, hard arteries. This helps keep plaque from forming in the arteries.
  • Lowering triglyceride levels by slowing the rate they form in the liver. High levels of triglycerides in the blood increase the risk of heart disease.
  • Less inflammation. Atherosclerosis (hardening of the arteries) is thought to involve your body's inflammatory response. Omega-3 fatty acids slow production of substances that are released during the inflammatory response.

Omega-3 fatty acids may also:

  • Raise levels of high-density lipoprotein (HDL/“good” cholesterol).
  • Lower blood pressure. People who eat fish tend to have lower blood pressure than those who don’t.

Amount of Omega-3 Fatty Acids in Selected Fish and Seafood

  • Mackerel
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 2.5–2.6 grams
  • Salmon (wild)
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 1.8 grams
  • Herring
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 1.3–2 grams
  • Tuna (Bluefin)
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 1.2 grams
  • Lake Trout
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 2 grams
  • Anchovy
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 1.4 grams
  • Tuna (Albacore)*
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 1.5 grams
  • Lake White fish (freshwater)
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 1.5 grams
  • Bluefish
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 1.2 grams
  • Halibut
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 0.9 grams
  • Striped Bass
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 0.8 grams
  • Sea Bass (mixed species)
    • Serving Size: 3 ounces (100 grams)
    • Amount of Omega-3 Fat: 0.65 grams
  • Tuna, white meat canned
    • Serving Size: 3 ounces drained
    • Amount of Omega-3 Fat: 0.5 grams

*Contains high level of Mercury. Limit amount you eat.

Source: USDA Food Composition Databases

How much Omega-3 do I need?

The American Heart Association recommends that patients who do not have a history of heart disease eat at least 2 servings of fish each week (a total of 6-8 ounces). This should include a variety of fish. Cold-water wild varieties of fish like mackerel, tuna, salmon, sardines and herring contain high amounts of omega-3 fatty acids. See the list above to help choose fish with high levels of omega-3 fatty acids.

If you have heart disease, your healthcare professional may recommend that you have one gram of EPA +DHA every day. If you have trouble getting this amount through food alone, talk to your doctor about taking a fish oil supplement.

If you have high triglyceride levels, you may need to eat more foods that are good sources of omega-3 fatty acids, even if you take medication to lower your triglyceride levels. Your healthcare provider may also want you to take a fish oil supplement. In general, 2-4 grams of EPA + DHA every day is recommended for patients with high triglyceride levels. This amount has been shown to lower triglyceride levels 25 to 35 percent.

Can you have too many omega-3 fatty acids?

Talk to your healthcare provider if you have 3 grams or more of omega-3 fatty acids in your diet each day. High levels of these essential fatty acids can cause bleeding.

Should I be concerned about mercury in fish?

Mercury occurs naturally in the environment and as a result of industrial pollution. It falls from the air and can collect in streams and oceans, where it is converted into methylmercury. Too much methylmercury can be harmful. This is especially true for unborn and young children.

Some fish have higher levels of mercury than others. These include shark, swordfish, tilefish, and King mackerel. Everyone should limit the amounts of these fish in their diet. Women who are pregnant or nursing and young children should not eat these types of fish. Women who are pregnant or nursing can safely eat 12 ounces of other types of fish each week. These include shellfish, canned fish and smaller fish.

Albacore Tuna has more mercury than canned light tuna. Limit the amount of albacore tuna you eat to 6 ounces per week.

What if I’m allergic to fish or don’t want to eat fish?

Fish is the best food source of omega-3 fatty acids, but several plants contain ALA. This is not as rich of a source of omega-3 fatty acids, but some studies show that ALA can reduce the risk of cardiovascular disease.

Good sources of ALA are ground or milled flaxseeds, flaxseed oil, chia seeds, walnuts, soy foods and canola oil. Another source of ALA is algae or algae oil, which is broken down to DHA. Many foods that are fortified with omega-3 use algae oil. These are excellent options for vegetarians that do not eat fish.

There are currently no serving size recommendations for ALA-rich foods. But, adding these foods to your diet regularly may help your heart health.

Last reviewed by a Cleveland Clinic medical professional on 01/02/2019.

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy