Triglycerides

What are triglycerides?

Triglycerides are the most common type of fat in the body and in food, and they are an important source of energy. Excess calories that are not used right away after meals, especially energy from sugar, refined carbohydrates, alcohol and fats, are converted into triglycerides and stored in fat tissue. Between meals, when the body needs energy, these stores are released back into the blood.

Because triglycerides do not dissolve in water, they are carried in the blood by lipoproteins; chylomicrons coming from the intestine after a meal and VLDL produced in the liver during fasting play a role in this transport. For this reason the triglyceride level is markedly affected by the last meal and rises in the hours after eating. In the laboratory, the amount of triglycerides in the serum is determined by enzyme-based color reactions; the result usually appears in the same report as the cholesterol values.

When is a triglyceride test ordered?

Triglycerides are used together with cholesterol tests to assess the risk of heart and blood vessel disease. Because very high levels can cause inflammation of the pancreas, the test is also particularly important for people at risk of this. It may also be ordered to assess metabolic status in people with suspected fatty liver or insulin resistance. Your doctor may repeat the test at intervals to see the effect of dietary changes or treatment.

• Routine cardiovascular risk assessment as part of the lipid profile
• Diabetes, insulin resistance, excess weight or metabolic syndrome
• Fatty liver or regular alcohol consumption
• Previous pancreatitis or a family history of high triglycerides
• Use of certain medications that can raise triglycerides

How do you prepare for a triglyceride test?

Among the lipid tests, triglycerides are the value most affected by meals; you therefore need to fast for 9–12 hours before the test. While fasting, you should consume nothing but plain water; sweetened or milky drinks and fruit juices can raise triglycerides quickly. Eating dinner early and giving blood the next morning before breakfast is an easy way to meet this fasting period.

Because alcohol raises triglycerides markedly, it is recommended that you avoid alcohol for at least 24 hours before the test. It is advisable to avoid very fatty or sugary foods the evening before the test, but not to change your usual diet of the previous weeks. Treatments such as cortisone, some hormone medications and some blood pressure medications can also affect the result, so tell your doctor about your medications. You can give your blood sample to a nurse on an empty stomach, at your home or workplace.

What does a triglyceride result mean?

High triglycerides are mostly associated with excess weight, physical inactivity, a diet rich in sugar and refined carbohydrates, alcohol use and uncontrolled diabetes. An underactive thyroid gland, kidney disease, inherited lipid disorders and some medications can also raise the value. High triglycerides increase the risk of cardiovascular disease, especially when combined with low HDL; very high levels carry a risk of acute pancreatitis. High triglycerides usually cause no symptoms; only at very high levels may abdominal pain or small yellow fatty deposits in the skin appear.

In a sample not taken on an empty stomach, triglycerides can be temporarily high; in such a case your doctor may want to repeat the test after fasting. Low triglycerides usually cause no problems, but they may rarely be associated with malnutrition, malabsorption disorders or an overactive thyroid gland. Reference values can vary by age, sex and laboratory; you can find the range of the laboratory that performs your test on this page. Your triglyceride result should be evaluated by your doctor together with your other lipid values, your symptoms and your overall risk profile.