Like cholesterol, triglycerides are common types of fats (lipids) that are essential for good health when present in normal amounts. They account for about 95 percent of the body’s fatty tissue. Triglycerides are present in food as well as manufactured by the body.

Abnormally high triglyceride levels are associated with a number of diseases and conditions, such as cirrhosis (a disease of the liver), underactive thyroid gland(hypothyroidism), diabetes and pancreatitis (inflammation of the pancreas).

High triglyceride levels are also associated with known risk factors for heart disease, such as low levels of HDL (“good”) cholesterol, high levels of LDL ("bad") cholesterol and obesity. Additionally, triglycerides may contribute to a type of thickening of artery walls, a physical change believed to be a predictor of hardening of the arteries (atherosclerosis). Researchers are continuing to investigate how triglycerides affect cardiovascular health.

At the very least, high triglyceride levels are a warning sign that a patient’s heart health may be at risk. In response, physicians may be more likely to stress the importance of losing weight, getting enough exercise, quitting smoking, controlling diabetes and other strategies that patients can use to protect their own cardiovascular health.

According to the U.S. National Heart, Lung and Blood Institute, the most current classifications for triglyceride levels are as follows in milligrams per deciliter (mg/dL):