A triglyceride is a specific type of lipid, or fat, composed of a glycerol molecule and three fatty acids. Triglycerides comprise over 95 percent of the fats in your diet, and your fat and muscle cells use triglycerides to store energy. Along with cholesterol, triglycerides have been implicated in several diseases, including heart attacks, strokes and fatty liver. Knowing your triglyceride level is important, but fluctuations among tests drawn at different times or by different laboratories can be confusing.
Disease Risk
Hypertriglyceridemia, meaning "high blood triglycerides," has been linked to several health disorders. In 1998, the Danish Male Study demonstrated that a high fasting triglyceride level is a strong risk factor for coronary heart disease. High triglycerides are also linked to diabetes and metabolic syndrome, both of which are risk factors for cardiovascular disease. A 33-year European study published in 2011 showed that elevated triglyceride levels are associated with higher stroke risk in both men and women.
Fasting or Fed?
According to Dr. Mark Deeg of Indiana University School of Medicine, your triglyceride level normally varies up to 30 percent from one day to the next. Any change in your diet during the two weeks prior to your test can increase this "background" fluctuation. If your blood test is performed after a fast, some of this day-to-day variability is eliminated. Therefore, you should adhere to your usual diet for at least two weeks prior to your test, and you should fast for 12 hours before your blood draw.
Weight Loss
Weight loss, particularly if it is sudden and dramatic, can cause marked changes in your serum triglyceride level. Adipose tissue is a major storage depot for triglycerides, and weight loss liberates triglycerides into your bloodstream, where they will be measured when your lipid panel is drawn. Your weight should be stable for at least two weeks prior to having your triglycerides checked.
Lifestyle
Because muscular activity consumes energy molecules -- including fatty acids -- exercise tends to lower your triglyceride levels. Although regular exercise is one way to lower your triglyceride levels, if exercise is not part of your routine, you should avoid it for 24 hours prior to your test. Alcohol consumption, a high-carbohydrate diet and poorly controlled diabetes can all increase your triglyceride level. Pharmaceutical agents, such as blood pressure medications, diuretics and bile acid binding resins can raise or lower your triglycerides, depending on the agent involved.
Considerations
A triglyceride level above 150 mg/dL is associated with health risks. Ascertaining your triglyceride level can help you to assess your chances of developing cardiovascular disease, diabetes and fatty liver. The normal daily variation in triglycerides can be nullified to some extent by having your blood drawn in a "steady state" -- no recent changes in activity, diet, weight, alcohol consumption or medications -- following a 12-hour fast. If you are having trouble interpreting your lipid panel results, consult your doctor.
References
- "Circulation"; Triglyceride Concentration and Ischemic Heart Disease: An Eight-Year Follow-up in the Copenhagen Male Study; J. Jeppesen, et al.; March 1998
- "American Family Physician"; Metabolic Syndrome: Time for Action; D. Deen; June 2004
- "Annals of Neurology"; Nonfasting Triglycerides, Cholesterol and Ischemic Stroke in the General Population; A. Varbo, et al.; February 2011
- "Lipid Topics"; Variations in Lipid Values; M. Deeg; June 2006
