Triglycerides are a form of fat found in food and in the body. In the body, they are usually found in the blood along with cholesterol, forming plasma lipids. Triglycerides are formed when fats are eaten in the diet. They can also be synthesized from excess intake of carbohydrates and then stored in the body if not used for energy. High triglycerides are a risk factor for heart disease.
Omega-3 fatty acids are a type of polyunsaturated fatty acid that has been shown to be able to lower triglycerides. The mechanism by which this occurs is not completely clear, but overall omega-3s decrease lipogenesis, or synthesis of lipids. There are four primary areas in this process of fat metabolism where omega-3s exert their effects.
Increased Beta Oxidation
Fats are consumed in the diet, broken down and then initially go to fat tissue and muscle. Whatever is left is taken to the liver. Before the triglycerides can be taken into fat and muscle tissue it has to be broken down, which is a process known as beta oxidation. Omega-3 fatty acids work in this initial step to increase beta oxidation so that a smaller amount of triglyceride is left over for transport to the liver to be repackaged for circulation in the bloodstream, according to LipidsOnline.com.
Decreased Triglycerides Delivered to Liver
Triglycerides contribute to plaque build up in the blood stream, which increases the risk for a heart attack. A study published in the April 2003 "American Journal of Clinical Nutrition" explains that fatty acid delivery to the liver is major determinant of triglycerides making it into the bloodstream. A result of increased beta oxidation is that a smaller amount of triglycerides are available to the liver, which then means triglycerides are not repackaged and released into the bloodstream.
Decreased Production of Triglycerides
One place fatty acid synthesis occurs is in the liver. This process involves packaging of any remaining triglycerides for travel in the bloodstream. Omega-3 fatty acids work in this step as well to decrease the synthesis of fat so that triglycerides are not released into the circulation, as explained in LipidsOnline.com.
Decreased Enzyme Activity
Within lipid metabolism, enzymes assist with converting fat into a form that allows for transport throughout the body. Enzymes are very critical to have for these reactions to occur. However, if they are not present or are working poorly, then the triglycerides are not packaged into a suitable form for leaving the liver. Omega-3 fatty acids appear to decrease the activity of enzymes that are needed to release the triglycerides into circulation, explains a study in the August 2006 journal "Current Opinions in Lipidology."
References
- Lipids Online: Role of Omega-3 Fatty Acids in Cardiovascular Disease Prevention
- "American Journal of Clinical Nutrition"; Plant- and Marine-derived N-3 Polyunsaturated Fatty Acids Have Differential Effects on Fasting and Postprandial Blood Lipid Concentrations and on the Susceptibility of LDL to Oxidative Modification in Moderately Hyperlipidemic Subjects; Yvonne Finnegan, et al.; 2003
- "Current Opinions in Lipidology"; Why do omega-3 fatty acids lower serum triglycerides?; Harris, et al.; 2006
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