Triglyceride test definition and facts
- Triglycerides are the main ingredient in vegetable oils and animal fats.
- The triglyceride test measures the level of triglycerides in the blood.
- Fasting for 9 to 12 hours before the triglyceride test is required.
- Elevated triglyceride levels may be a risk factor for atherosclerosis. Highly elevated triglyceride levels may also cause fatty liver disease and pancreatitis.
- High triglyceride levels can also be associated with diabetes, kidney disease, and the use of some medications.
- Normal triglyceride levels in the blood are less than 150 mg per deciliter (mg/dL).
- Triglyceride levels can be controlled to some extent by lifestyle modifications and, when necessary, medications.
What are triglycerides?
Triglycerides are chemical compounds digested by the body to provide it with the energy for metabolism. Triglycerides are the most common form of fat in the body. They are the main ingredient in vegetable oils and animal fats.
The triglyceride molecule is a form of the chemical glycerol (tri=three molecules of fatty acid + glyceride=glycerol) that contains three fatty acids. To be absorbed, these parts are broken apart in the small intestine, and afterwards are reassembled with cholesterol to form chylomicrons. This is the source of energy for cells in the body. Fat cells and liver cells are used as storage sites and release chylomicrons when the body needs the energy.
Elevated triglyceride levels are a risk factor for atherosclerosis, the narrowing of arteries with the buildup of fatty plaques that may lead to heart attack, stroke, and peripheral artery disease. Markedly elevated triglyceride levels may also cause fatty liver disease and pancreatitis.
Certain diseases and conditions may cause elevated triglyceride blood levels, for example:
- Poorly-controlled diabetes
- Kidney disease
- Cirrhosis of the liver or other liver diseases
- Some medications (for example, beta blockers, diuretics, birth control pills)
Alcohol consumption can raise triglyceride blood levels by causing the liver to produce more fatty acids. However, there are some beneficial aspects of moderate alcohol consumption, defined as one alcoholic beverage per day (a glass of wine, a bottle of beer, or an ounce of hard liquor), that may balance this triglyceride rise. Moderate alcohol consumption may mildly increase HDL (the good cholesterol) levels in the bloodstream and red wine, which contains antioxidants, may decrease the risk of heart disease. However, it is not recommended that people start to drink alcohol to obtain these effects.
How are triglyceride levels measured?
Triglyceride levels in the blood are measured by a simple blood test. Often, triglycerides are measured as part of a lipoprotein panel (lipid panel) in which triglycerides, cholesterol, HDL (high-density lipoprotein), and LDL (low-density lipoprotein) are measured at the same time.
Fasting for 8-12 hours before the test is required. Fat levels in the blood are affected by recent eating and digestion. Falsely elevated results may occur if the blood test is done just after eating.
What are normal triglyceride levels? What do elevated triglyceride levels mean?
Elevated triglycerides place an individual at risk for atherosclerosis. Triglyceride and cholesterol levels are measured in the blood to provide a method of screening for this risk.
- Normal triglyceride levels in the blood are less than 150mg per deciliter (mg/dL).
- Borderline levels are between 150-200 mg/dL.
- High levels of triglycerides (greater than 200 mg/dl) are associated with an increased risk of atherosclerosis and therefore coronary artery disease and stroke.
- Extremely high triglyceride levels (greater than 500mg/dl) may cause pancreatitis (inflammation of the pancreas).
How can I lower my triglyceride levels?
Returning triglyceride levels to normal may decrease the risk of heart attack, stroke, and peripheral artery disease. Controlling high triglycerides and high cholesterol is a lifelong challenge. A healthy lifestyle includes eating well, exercising routinely, smoking cessation, and weight loss. This may be all that is needed, but some people additionally require medications to lower triglyceride levels in the blood. Your health-care professional will help make decisions with you to decide what treatment combination is most appropriate.
Changes in diet to lower triglycerides
The following dietary changes may be helpful in lowering triglycerides.
- Decreasing your intake of sugar: If you have a sweet tooth, try to set limits on how often and how much sugar you consume. You can cut your intake in half to begin with, and continue cutting back from there. Remember to read the labels to check for sugar content in both food and beverages.
- Changing from white to brown: If you eat white rice, bread, and pasta, switch to whole wheat products. It may take a little while to get used to the difference in taste, but it's worth the effort for the benefits to your health. A variety of whole-wheat products are available so experiment until you find the one that you like best.
- Switching fats: Limit or avoid foods with saturated and trans fats. These include fried foods, lard, butter, whole milk, ice cream, commercial baked goods, meats, and cheese. Read the nutrition labels to determine whether these unhealthy fats are present.
Switch to monounsaturated and polyunsaturated fats instead of trans or saturated fats. The best sources of these fats are olive oil, canola oil, nuts, and fatty fish like salmon, mackerel, lake trout, sardines, herring, and albacore tuna. Learning to interpret food labels will help you understand the kinds of fat in the food you buy and consume.
Jameson, JL, et al. Harrison's Principles of Internal Medicine, 20th ed. (Vol.1 & Vol.2). McGraw-Hill Education 2018.
University of Massachusetts Medical School. Triglycerides.