Triglycerides

Triglycerides are a major type of lipid and the main storage form of fat in animals. Chemically, a triglyceride consists of glycerol bound to three fatty acids via ester bonds. In the body they are stored in adipose tissue and circulate in the bloodstream within lipoproteins.

Triglycerides provide energy. When energy is needed, adipose tissue undergoes lipolysis, releasing fatty acids for use by tissues. Dietary triglycerides are absorbed and packaged into chylomicrons; liver-derived triglycerides are packaged into very low density lipoproteins (VLDL) for delivery to tissues.

Circulating triglycerides are carried mainly in lipoproteins. Enzymes such as lipoprotein lipase hydrolyze triglycerides in chylomicrons and VLDL, releasing fatty acids for tissue uptake and generating remnant particles cleared by the liver. After meals, triglyceride levels rise transiently and then return to baseline with time.

Fasting triglyceride levels are used to assess risk. Normal levels are typically below 150 mg/dL; levels above 200 mg/dL are considered high and are associated with pancreatitis risk and metabolic syndrome, especially when accompanied by other lipid abnormalities.

Management focuses on lifestyle changes: weight control, regular exercise, and limiting refined carbohydrates and alcohol. Pharmacologic options include fibrates and prescription omega-3 fatty acids; statins may modestly reduce triglycerides, depending on the profile, but are primarily used to lower LDL cholesterol.