Triglycerides are a type of fat, or lipid, that circulates in the bloodstream and is stored in fat cells. They function primarily as a major energy source, utilized by the body between meals when fuel is needed. While high triglycerides are a known risk factor for heart disease, public health messaging often overlooks the possibility of levels dropping too low. This less common scenario, known as hypotriglyceridemia, can signal underlying health issues that warrant medical attention.
Defining Low Triglyceride Levels
Triglyceride levels are measured through a blood test, typically in milligrams per deciliter (mg/dL), after a period of fasting. A normal fasting level is considered less than 150 mg/dL. Levels above this threshold are classified as high and are associated with increased cardiovascular risk.
Unlike the clearly defined high ranges, there is no universally agreed-upon clinical threshold for a “low” triglyceride level. Some laboratories consider levels below approximately 50 mg/dL to be low, though this number varies. This lack of a standard reflects that low levels are generally not viewed as a primary health threat.
Hypotriglyceridemia describes an unusually low concentration of these fats in the blood. For most people, a reading slightly below the normal range indicates a healthy diet or efficient metabolism. Extremely low levels, however, may be categorized as a hypolipidemic state, suggesting a disruption in the body’s normal fat processing.
Underlying Causes of Low Triglycerides
Low triglyceride levels often result from lifestyle choices or certain medications. A very low-fat diet, restricted calorie intake, or prolonged fasting depletes circulating fat stores. This occurs because the body utilizes stored fat for energy, lowering the amount measured in the blood.
Medications
Medications prescribed to manage high cholesterol can significantly reduce triglyceride levels. Drugs such as fibrates are specifically designed to lower these fats. High doses of fish oil supplements, rich in omega-3 fatty acids, are also known to have a triglyceride-lowering effect.
Metabolic and Absorption Issues
Medical conditions that increase the body’s metabolic rate or impair nutrient absorption are frequent causes. Hyperthyroidism (an overactive thyroid) accelerates metabolism, causing fats to be broken down faster than usual. Malabsorption syndromes, such as Celiac disease or Crohn’s disease, prevent the small intestine from properly absorbing dietary fats.
Other Health Conditions
Other causes include malnutrition, where a deficiency in necessary nutrients leads the body to use up fat reserves. Liver diseases, which disrupt the production and processing of fats, can also impair normal lipid metabolism. In rare instances, extremely low triglycerides are caused by genetic disorders, such as abetalipoproteinemia, which impairs the transport of fats.
Health Implications of Very Low Triglycerides
For most people, a low triglyceride reading is positive, often associated with a reduced risk of cardiovascular disease. When levels are extremely low, however, the primary concern is that the result signals a serious, undiagnosed health problem. Investigating the root cause is usually more important than treating the low number itself.
Very low levels may be accompanied by vague symptoms, such as persistent fatigue or weakness, since triglycerides are a primary energy source. If the low level is due to malabsorption or malnutrition, the person may also experience unintended weight loss. These symptoms stem from the underlying disorder, not the low triglycerides directly.
A significant physiological consequence of very low fat levels is the potential for fat-soluble vitamin deficiencies. The absorption of vitamins A, D, E, and K relies on the presence of dietary fat in the small intestine. Sustained, severely low circulating fat can impair this absorption process, leading to deficiencies over time.
When very low triglycerides are observed, a healthcare provider performs a comprehensive evaluation to rule out conditions like hyperthyroidism or malabsorption disorders. While a slightly low reading is often beneficial, a reading below 50 mg/dL should prompt a closer look at diet, medication, and overall metabolic health to ensure any underlying issue is identified and addressed.