Fish Oil and Omega-3 Fatty Acids

Omega-3 fatty acids have become quite popular as of late owing to their many positive effects on human health. Omega-3 fatty acids benefit both healthy people as well as those with cardiovascular disease. Omega-3 fatty acids are thought to improve heart health by lowering triglycerides, raising good cholesterol (HDL, or high density lipoprotein), thinning the blood preventing blood clots from forming, and protecting the heart from dangerous heart rhythms. Omega-3 fatty acids may also slow the progression of plaque build-up and lower blood pressure. In Italy, they are given routinely to heart attack patients and in other fields of medicine because omega-3 fish oils are thought to have anti-inflammatory effects.

 

Source

Omega-3 fatty acids are essential to health but cannot be produced by the body. Three different forms of omega-3 fatty acids exist: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA). ALA is found in plant sources (flaxseed oil) and food (flaxseeds, walnuts, tofu). EPA and DHA come from seafood, especially fatty fish such as salmon.

Fish	EPA Content (G/100 G)	DHA Content (G/100 G)	EPA + DHA (G/100 G)
Salmon (Atlantic)	0.690	1.457	2.147
Mackerel	0.504	0.699	1.203
Tuna (fresh)	0.283	0.890	1.173
Trout (Rainbow)	0.334	0.820	1.154
Tuna (canned)	0.233	0.629	0.862
Sworfish	0.138	0.681	0.819
Sea Bass	0.206	0.556	0.762
Flounder	0.243	0.258	0.501
Halibut	0.091	0.374	0.465
Crab (Alaskan King)	0.295	0.118	0.413
Shrimp	0.171	0.144	0.315
Catfish (farmed)	0.049	0.128	0.177
Cod	0.004	0.154	0.154

*From United States Department of Agriculture Nutrient Data Laboratory

Important Note: Health food stores carry multiple different types of fish oil. While no specific brand is recommended, usually the mid-priced, generic brands are just as good as the very expensive brands. Expect to pay $15-$30 for a month's supply. The key is to ensure that the product is mercury-free, as pure as possible, and contains the right amount of EPA and DHA.

 

Treatment

The American Heart Association (AHA) recommends individuals without coronary heart disease eat a variety of fish, preferably fatty, at least twice a week. Increasing omega-3 fatty acid intake through dietary sources is preferable. Individuals with coronary heart disease are recommended to get 1 gram/day of EPA and DHA (or more). This amount of Omega-3 fatty acids would require considerable fish consumption to the extent that it is impractical for most. As such, fish oil supplements, either over the counter or pharmaceutical grade, are typically used to achieve recommended levels. This is particularly the case for individuals with high triglycerides which may require high levels of omega-3 fatty acid intake.

Population	Recommendation
Patients without documented coronary heart disease (CHD)	Eat a variety of (preferably fatty) fish at least twice a week. Include oils and foods rich in ALA (flaxseed, canola, and soybean oils; flaxseed and walnuts)
Patients with documented CHD	Consume about 1g of EPA+DHA per day, preferably from fatty fish. EPA+DHA in capsule form could be considered in consultation with a physician.
Patients who need to lower triglycerides	2 to 4 grams of EPA+DHA per day provided as capsules under a physician's care.

*From the American Heart Association  

 

Side Effects

Omega-3 fatty acids are essentially free of side effects at generally recommended doses (1 to 4 g/day). Although rare, side effects generally consist of a fishy aftertaste and/or gastrointestinal upset. These side effects can be minimized by freezing the capsules or taking the supplements at night.

Predatory fish such as shark, swordfish, tilefish, and mackerel contain higher levels of mercury and should be avoided by nursing or pregnant women. However, fish oil contains only inconsequential levels of mercury and is felt to be free of mercury-related toxicities.

Theoretical concerns of increased bleeding have been largely dismissed due to a number of clinical studies which have failed to demonstrate any change in bleeding. High doses of omega-3 fatty acids (less than 3 g/day) have been associated with slight rise in bad cholesterol (low density lipoprotein, or LDL) and blood sugar.

 

Goals

In the highest risk patients, improving cholesterol levels with a goal LDL less than 70 and HDL greater than 40-45 with triglycerides under 150 mg/dL along with an extensive lifestyle modification is critical to achieve clinical success. Talk to your doctor today about incorporating fish oil and other beneficial changes in your life to prevent heart disease.

 

This information has been approved by Brett Fenster, MD, and Andrew Freeman, MD (February 2010).