Triglycerides are a type of lipid that circulates in the bloodstream and serves as the primary way the body stores energy for later use. When calories are consumed in excess, especially from carbohydrates, the body converts them into triglycerides for storage in fat cells. Although the public conversation typically focuses on the dangers of abnormally high triglyceride levels, which are linked to cardiovascular risk, levels that are too low can also signal significant underlying health issues. Extremely low values suggest the body is not absorbing, producing, or storing enough fat to maintain normal metabolic functions.
Context: Defining Normal and Dangerously Low Ranges
The typical goal for a healthy fasting triglyceride level is less than \(150 \text{mg/dL}\). Many health professionals consider an optimal level to be under \(100 \text{mg/dL}\), as this range is associated with better cardiovascular outcomes. Levels are considered low when they fall below the standard normal range, typically defined as under \(50 \text{mg/dL}\).
The threshold for a “dangerously low” or abnormally low level is generally considered to be below \(40 \text{mg/dL}\). While a low level in an otherwise healthy person might reflect an efficient metabolism or a very low-fat diet, a persistent measurement below \(40 \text{mg/dL}\) warrants a thorough medical investigation. These very low measurements are medically known as hypotriglyceridemia and often serve as a biomarker for a systemic problem.
Underlying Causes of Abnormally Low Levels
One of the most common reasons for abnormally low triglycerides is severe nutritional deficit or chronic malabsorption. Conditions involving chronic undernutrition, such as anorexia nervosa or severe restrictive diets, prevent the body from taking in the necessary fats and calories to form triglycerides. Similarly, malabsorption disorders like Celiac disease, Crohn’s disease, or chronic pancreatitis impair the small intestine’s ability to absorb dietary fat, resulting in a systemic lack of circulating triglycerides.
A hyperactive thyroid gland, known as hyperthyroidism, is another frequent cause of decreased triglyceride levels. Excess thyroid hormones accelerate the body’s metabolic rate, causing a rapid burn-off of stored energy, including triglycerides. This consumes lipids faster than the body can synthesize and store them, resulting in a consistently low measurement often accompanied by symptoms like unexplained weight loss or a rapid heartbeat.
In rare cases, very low triglycerides result from specific inherited genetic defects that interfere with lipid metabolism. Disorders like abetalipoproteinemia or familial hypobetalipoproteinemia prevent the body from properly assembling or transporting lipoproteins, which carry fat through the bloodstream. These genetic conditions directly impair the synthesis of very-low-density lipoprotein (VLDL) and chylomicrons, the main carriers of triglycerides. Certain prescription medications can also push triglyceride levels to a low point, most notably high doses of lipid-lowering drugs like fibrates or statins.
Health Consequences of Very Low Triglycerides
Insufficient triglycerides impair energy storage and nutrient transport. When levels are extremely low, the body struggles to maintain adequate energy reserves, often manifesting as chronic fatigue and significant weight loss. The lack of available fat also hinders the body’s ability to efficiently use fat for fuel between meals.
Prolonged hypotriglyceridemia causes the malabsorption of fat-soluble Vitamins A, D, E, and K. Since these vitamins require dietary fat for absorption in the small intestine, a deficiency in triglycerides means these essential micronutrients cannot be taken up by the body. For example, a lack of Vitamin A can lead to vision impairment, while low Vitamin K can result in poor blood clotting and increased bruising.
The nervous system is vulnerable to very low fat levels because lipids are an integral part of nerve cell membranes and the insulating myelin sheath. Insufficient lipid supply can contribute to neurological symptoms, including muscle weakness, poor coordination, and cognitive effects like difficulty concentrating. A lack of essential fatty acids, derived from dietary fats, can also lead to visible symptoms such as dry, flaky skin and abnormal hair development.
Diagnosis and Management
The initial step in identifying abnormally low triglycerides is a standard blood test called a lipid panel, which measures various fats in the blood after a 9-to-12-hour fast. If results are persistently low, diagnosis focuses on systematically ruling out or confirming the underlying condition. This often involves additional blood work, such as thyroid function tests, or specific tests for malabsorption disorders.
Management strategies depend entirely on the root cause identified. If a restrictive diet or malnutrition is the cause, treatment involves nutritional counseling to ensure an adequate intake of healthy fats, such as those found in avocados, olive oil, and fatty fish rich in omega-3 fatty acids. For patients with hyperthyroidism, treating the overactive gland typically resolves the low triglyceride levels.
If a medication is implicated, the prescribing physician may adjust the dosage or switch the patient to an alternative drug. In cases of genetic disorders or severe malabsorption, treatment may include specialized dietary supplements, such as high-dose fat-soluble vitamins, to prevent long-term deficiency complications.