Omega-3 is a type of unsaturated fatty acid that plays an important role in brain function and normal growth and development. Unsaturated fats, such as the type you see in oils, have at least one double bond in their chemical structure. This makes them appear less dense than the saturated fats endemic to animal fat. The name omega-3 refers to the location of the first double bond: on the third carbon atom in the molecule. The unique characteristics of omega-3 have a positive effect upon your body's lipid profile.
Lipid Profile
Lipid profile, or lipid panel, is the collective name given to various lipids in the blood that help assess the risk of heart disease. There are two major classes of fats in a lipid profile. The first is triglycerides, the main transport and storage form of fat in your body. The second is cholesterol, a type of waxy steroid that has a variety of functions. The liver packages cholesterol within molecules known as lipoproteins for transport through your blood. Lipoproteins are made out of combinations of fats and proteins. They range in density from very-low-density lipoproteins, or VLDL, which contain more fat, to high-density lipoproteins, or HDL, which contain more protein. Any cholesterol that builds up in the arteries can lead to heart disease. VLDL and LDL tend to deposit cholesterol in the bloodstream, but HDL transports cholesterol back to the liver for excretion and actually reduces the risk of heart disease.
Evidence
The medical literature exploring the effects of omega-3 is large and extensive and has shown a generally beneficial effect upon the lipid profile. A 2007 study published in the "American Journal of Health System Pharmacy" found that omega-3 reduced triglycerides by an average of 45 percent and VLDL cholesterol by more than 50 percent in patients with high triglyceride levels of at least 500 mg/dL of blood. Other studies have also demonstrated an increase in HDL. However, the precise degree of change has not always been consistent among studies, suggesting that there are other factors at work.
Effects
Omega-3 fatty acids lower lipids in the blood by inhibiting the production of VLDL and triglycerides in the liver. The exact mechanism is still somewhat speculative. Omega-3 appears to reduce lipogenesis, the process by which the body synthesizes fats, and increases beta-oxidation, or the breakdown of fatty acids. Lipogenesis results in the production of triglycerides, which are then packaged inside of VLDL for transportation through the blood. Reducing the rate of lipogenesis will therefore have an effect on the production of VLDL. However, the extent of this effect is not fully known.
Dietary Sources and Recommended Intake
Omega-3 is primarily found in fish, the form in which it is most effective, although it's also found in certain types of plant oil such as canola and flaxseed. The American Heart Association recommends consuming two servings of fish per week if you have no history of coronary heart disease and a serving per day if you do have a history. You may also need a dosage of 2 to 4 g per day to reduce elevated triglyceride levels. Omega-3 is available in fish oil supplements. Talk to your doctor before taking any supplements.
References
- Lab Tests Online; Lipid Profile; March 2011
- "American Journal of Health System Pharmacy"; Prescription Omega-3 Fatty Acids for the Treatment of Hypertriglyceridemia; James M. McKenney, et al.; March 2007
- American Academy of Family Physicians; Omega-3 Fatty Acids; Maggie B. Covington; 2004
- "Current Opinion in Lipidology"; Why Do Omega-3 Fatty Acids Lower Serum Triglycerides?; W.S. Harris, et al.; August 2006
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