Triglycerides are a form of lipid, or fat, created by combining one molecule of glycerol with three fatty acid molecules. According to "The Merck Manual of Diagnosis and Therapy," triglycerides make up more than 95 percent of the fat in your diet, and they are the principal form of fat storage in your adipose tissue. Your liver is responsible for much of the triglyceride metabolism in your body, but too many triglycerides can actually damage this important organ.
Digestion and Absorption
Whenever you consume a fatty meal, digestive enzymes called lipases break the triglycerides into fatty acids, monoglycerides and diglycerides. The cells lining your intestine then absorb these fatty acids and triglyceride fragments. Smaller fatty acids can be transported directly through your bloodstream to your liver, but larger fatty acids and mono- and diglycerides are reassembled into triglycerides and packaged with cholesterol into water-soluble molecules called chylomicrons. Chylomicrons enter the lymphatic channels surrounding your intestine and they, too, are eventually carried to your bloodstream.
Triglyceride Sources
Dietary fat is only one source of triglycerides. If you consume more carbohydrates than your tissues can immediately use for energy, much of the excess is converted to fatty acids and then to triglycerides through a process called lipogenesis. Your liver is a principal site of lipogenesis; the triglycerides produced in your liver are either stored there or packaged into chylomicrons and released into circulation. Fatty acids released from your adipose tissue are another potential source of triglycerides that your liver must eventually process.
Fatty Liver
When the triglycerides in your bloodstream overwhelm your liver's capacity to immediately process them, they are stored within your liver's cells until they can be metabolized. However, this creates an inflammatory condition that can injure your liver's cells and trigger the release of their internal enzymes into your bloodstream. A June 2006 review in "American Family Physician" reported that this condition, called fatty liver or steatosis, is the most common cause of elevated liver enzymes in the United States. Notably, the incidence of steatosis becomes greater with increased body weight.
Considerations
An elevated serum triglyceride level -- due to high-fat or high-carbohydrate diets, genetic lipid disorders, obesity, diabetes or other physiologic abnormalities -- places a strain on your liver's processing ability. A well-balanced diet, regular exercise and maintaining optimal body weight are the best ways to help your liver metabolize triglycerides and avoid fatty liver disease.
References
- "The Merck Manual of Diagnosis and Therapy, 18th Edition: Lipid Disorders"; Mark H. Beers, M.D., Editor-in-Chief; 2006
- "American Family Physician"; Nonalcoholic Fatty Liver Disease; M. Bayard, et al.; June 2006
