Omega-3 Fatty Acids - heart healthy benefitsEarly Arctic explorers noted that the Eskimos, despite their consumption of high-fat and high-cholesterol foods, had a very low incidence of heart disease. Scientists and physicians were stumped and considered it a paradox, until they looked more closely at their diets. What they found has changed the way nutrition and health care professionals prevent and treat heart disease today: The Eskimo's diets were rich in omega-3 fatty acids.
What are omega-3 fatty acids?Omega-3 fatty acids are called essential fats because the body cannot produce them; they must be consumed from foods in order to survive. The primary dietary source of omega-3 is fish, although some plants also contain omega-3 fatty acids.
The form of omega-3 in plants is called alpha-linolenic acid (ALA). Although ALA does provide health benefits, its has a lesser effect on cardiovascular disease risk than EPA and DHA.
How are omega-3 fatty acids beneficial?Here's how omega-3 fatty acids may protect you from cardiovascular disease:
- Lower risk of sudden death. Omega-3 fatty acids have been shown to significantly reduce the risk of sudden death caused by cardiac arrhythmias and all-cause mortality in people with existing cardiovascular disease.
- Reduce blood clot formation. Omega-3 fatty acids act as a natural anticoagulant by altering the ability of platelets in the blood to clump together.
- Inhibit the growth of plaque. Omega-3 fatty acids help keep the lining of the arteries smooth and clear of damage that can lead to thickening and hardening of the arteries.
- Decrease triglycerides. High blood triglycerides are associated with an increased risk for heart disease. Omega-3 fatty acids decrease the rate at which triglycerides are produced in the liver.
- May increase levels of the good cholesterol, high-density lipoprotein (HDL). Because omega-3 fatty acids lower triglyceride levels, they may also increase HDL, the “good” cholesterol that protects against the development of heart disease.
- Have anti-inflammatory properties. The development of atherosclerosis (hardening of the arteries) is thought to involve the body’s inflammatory response. Omega-3 fatty acids reduce the production of substances that are released during the inflammatory response and in doing so, prevent substances from accumulating and sticking to the lining of the arteries.
- May lower blood pressure. Several studies have examined the effect of omega-3 fatty acids on blood pressure. Those who eat fish tend to have a lower incidence of high blood pressure.
How much omega-3 is recommended?The American Heart Association recommends that patients without documented coronary heart disease eat a variety of fatty fish (see list below) and aim for at least two servings per week (total of at least 6 ounces).
If you have heart disease, your health care professional may recommend you increase your food sources of omega-3 to reach a daily goal of one gram of EPA + DHA. If this amount is too difficult to achieve from diet alone, your health care provider may suggest taking a fish oil supplement.
If you have high triglyceride levels (including those who are taking triglyceride-lowering medications), your health care provider may also recommend you increase food sources of omega-3. If these strategies are not effective, your provider may tell you to incorporate fish oil supplements into your diet. To effectively lower triglycerides, 2-4 grams of EPA + DHA are recommended daily. Research studies have shown that this amount lowered triglycerides approximately 25 percent to 35 percent.
Note that a high intake of omega-3 fatty acids can cause bleeding in some people. Therefore, anyone who takes 3 grams or more of omega-3 fatty acids from supplements should be under a physician’s care.
|Fish||Serving Size||Amount of Omega-3 Fat|
|Atlantic Salmon or Herring||3 ounces cooked||1.9 grams|
|Blue Fin Tuna||3 ounces cooked||1.5 grams|
|Sardines, canned||3 oz. in tomato sauce||1.5 grams|
|Anchovies, canned||2 ounces drained||1.2 grams|
|Atlantic Mackerel||3 ounces cooked||1.15 grams|
|Salmon, canned||3 ounces drained||1.0 gram|
|Swordfish||3 ounces cooked||0.9. gram|
|Sole, Flounder, Mussels||3 ounces cooked||0.4 gram|
|Wild Catfish, Crabmeat, Clams||3 ounces cooked/steamed||0.3 gram|
|Prawns (Jumbo Shrimp)||6 pieces||0.15 gram|
|Atlantic Cod, Lobster||3 ounces cooked/steamed||0.15 gram|
|Trout, Orange Roughy||3 ounces cooked||<0.1 gram|
|Tuna, white meat canned||3 ounces drained||0.5 gram|
What about Mercury in Fish? Shouldn’t I be Concerned?Mercury occurs naturally in the environment and as a result of industrial pollution. It falls from the air and can accumulate in streams and oceans and is converted to methylmercury in the water. Methylmercury, in excess, can be harmful to health, especially the health of an unborn baby or young child.
Fish that are particularly high in mercury include shark, swordfish, tilefish, and King mackerel. These fish should be limited by everyone, and avoided by pregnant/nursing women and young children. Pregnant and lactating women can still safely eat 12 ounces/week of fish that are not high in mercury, including shellfish, canned fish (choose canned LIGHT tuna, which has lowest amount of mercury of canned tuna), smaller ocean fish, and farm-raised fish.
For more information on the mercury content in fish, please visit the US Department of Agriculture website at: www.cfsan.fda.gov/