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, raise good cholesterol (HDL, or high density lipoprotein), thin the blood to prevent blood clots from forming, and protect the heart from dangerous heart rhythms.
Omega-3 fatty acids also may slow the progression of plaque buildup and lower blood pressure. Omega-3 fatty acids are highly concentrated in the brain and appear to be important for cognitive (brain memory and performance) and behavioral function. Scientists believe the omega-3 fatty acid DHA may be protective against Alzheimer's disease and dementia. In Italy, omega-3a 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.
Where Omega-3s Come From
Omega-3 fatty acids are considered essential fatty acids; this means they 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, tuna and halibut. Although fish is a source of omega-3, fish themselves do not produce them. Rather, they are obtained from the algae (microalgae in particular) and plankton consumed in their diets.
EPA + DHA
Crab (Alaskan King)
*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.
The American Heart Association (AHA) has recommended that 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.
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
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.
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.
Studies on Omega-3s
Recent data suggest that there may not be as much of a benefit for taking fish oil regularly.
A 2008 meta analysis by the Canadian Medical Association Journal showed that fish oil supplementation did not give a preventative benefit to cardiac patients with ventricular arrhythmias.
A more recent 2012 meta-analysis published in the Journal of the American Medical Association (JAMA), analyzed 20 studies and nearly 70000 patients. This meta-analysis found that fish oil supplementation did not reduce the chances of death, cardiac death, heart attack or stroke. As such, many providers are no longer using fish oil as prophylaxis.
Fish oil has demonstrated benefit in the treatment of hypertriglyceridemia, but may also increase LDL (the bad cholesterol) in larger doses.
[Rizos, E. C.; Ntzani, E. E.; Bika, E; Kostapanos, MS; Elisaf, MS (2012). "Association Between Omega-3 Fatty Acid Supplementation and Risk of Major Cardiovascular Disease Events: A Systematic Review and Meta-analysis". Journal of the American Medical Association 308 (10): 1024–33.]
This information has been approved by Brett Fenster, MD, and Andrew Freeman, MD (February 2014).