N-3, or omega-3, polyunsaturated fatty acids are a healthy type of fatty acid that contains many benefits to health including a role in preventing coronary disease. Omega-3's are found in a variety of foods including cold water fish, flaxseed, canola oil and walnuts. Three primary types of omega-3 fatty acids exist such as alpha-linoleic acid, or ALA, eicosapentaeoic acid, or EPA, and docosahexaenoic acid, or DHA. These fats must be obtained by the diet since the body does not produce them.
Triglycerides and Omega-3 Fatty Acids
Omega-3 fatty acids have a triglyceride lowering effect. High triglycerides are a risk factor for heart disease. A study in the March 2003 "Journal of Lipid Research" assessed the effect of 4 g per day of EPA and 4 g per day of DHA on high triglycerides compared with a control of safflower oil for four weeks. Following the four weeks, EPA and DHA both lowered triglyceride levels in healthy participants. The mechanism of how this occurs is not completely understood. Potentially, EPA and DHA lower triglycerides by reducing the activity of the enzymes that create triglycerides, which causes a decrease in triglycerides released into the bloodstream from the liver.
Cardiac Arrhythmias
The American Heart Association encourages the use of omega-3 fatty acids for decreasing the risk of cardiac arrhythmias in a review of studies in the 2002 journal "Circulation." Arrhythmias are irregular heart beats. Researchers explained that the fatty acids in fish and fish oil act directly upon the heart to produce the positive effect of decreasing irregular heart beats. This study noted EPA and DHA reduce resting heart rates and are strong inhibitors of the sodium channels that regulate contraction of the heart muscle, potentially decreasing arrhythmias.
Blood Pressure
Omega-3's have been shown to reduce blood pressure, though modestly. Reductions in blood pressure decrease heart disease risk. The effect that omega-3's have on blood pressure depends on the degree of hypertension you have, according to the study in the 2002 journal "Circulation." Additionally, DHA appears to be more effective than EPA and the beneficial amount of DHA is a dose of more than 3 g per day.
Sources and Recommendations
Omega-3 fatty acids are found in flax oil, flaxseeds, walnuts, cold water fish and fish oil supplements. The omega-3's found in fish oil appear to be particularly beneficial for heart disease in comparison to the plant-based sources of omega-3's. The American Heart Association recommends obtaining omega-3's through eating fish before taking supplemental fish oil. Although if eating fish two times per week is difficult, then a supplement is recommended under a physician's supervision. People with coronary heart disease should take a fish oil supplement with EPA and DHA at a dose of 1 g per day. If you need to lower triglycerides, then aim for 2 g to 4 g per day of fish oil.
References
- "Today's Dietitian"; Ocean of Benefits; Megan Tempest, RD, LDN; March 2011
- American Heart Association: Fish 101
- "Journal of Lipid Research"; Omega-3 Fatty Acid Supplementation Accelerates Chylomicron Triglyceride Clearance; Yongsoon Park, et al.; 2003
- "Circulation"; Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease; Penny Kris-Etherton, et al.; 2002
- American Heart Association: Fish and Omega-3 Fatty Acids
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