What causes very low triglyceride levels?
Very low triglycerides (under 40 mg/dL) can result from hyperthyroidism, malnutrition, genetic conditions, or certain medications. While often less concerning than high levels, extremely low triglycerides may indicate underlying health issues requiring medical evaluation.
Understanding Triglycerides and Normal Ranges
Triglycerides are a type of fat (lipid) found in your blood that serve as an important energy source for your body. When you eat, your body converts calories it doesn't immediately need into triglycerides, which are stored in fat cells and released between meals when your body needs energy. While much attention is given to high triglyceride levels and their association with heart disease, very low levels can also signal underlying health conditions.
Normal triglyceride levels typically range from 50 to 150 mg/dL, with optimal levels considered to be under 100 mg/dL. Levels below 40 mg/dL are generally considered very low, though some laboratories use 35 mg/dL as the cutoff. Unlike high triglycerides, which are clearly linked to increased cardiovascular risk, the health implications of very low triglycerides are less straightforward and depend largely on the underlying cause.
Primary Causes of Very Low Triglycerides
Hyperthyroidism and Thyroid Disorders
An overactive thyroid gland (hyperthyroidism) is one of the most common causes of very low triglyceride levels. When your thyroid produces excess hormones, it accelerates your metabolism, causing your body to burn through fats more quickly than normal. This increased metabolic rate can lead to weight loss, increased appetite, and significantly reduced triglyceride levels. People with hyperthyroidism often have triglycerides below 50 mg/dL, and in severe cases, levels can drop below 35 mg/dL.
Triglyceride Level Categories and Clinical Significance
| Triglyceride Level | Category | Health Implications | Typical Action | |
|---|---|---|---|---|
| Below 35 | <35 mg/dL | Extremely Low | May indicate genetic disorder, severe malnutrition, or hyperthyroidism | Comprehensive evaluation needed |
| 35-50 | 35-50 mg/dL | Very Low | Could suggest thyroid disorder, malabsorption, or medication effect | Further testing recommended |
| 50-100 | 50-100 mg/dL | Optimal | Associated with lower cardiovascular risk | No action needed |
| 100-150 | 100-150 mg/dL | Normal | Acceptable range for most adults | Maintain healthy lifestyle |
| Above 150 | >150 mg/dL | High | Increased cardiovascular risk | Lifestyle changes, possible medication |
Triglyceride levels should be interpreted alongside other lipid values and clinical symptoms for accurate assessment.
The connection between thyroid function and lipid metabolism is complex. Thyroid hormones directly influence how your liver produces and clears triglycerides from the bloodstream. They also affect the activity of lipoprotein lipase, an enzyme that breaks down triglycerides. Regular monitoring of both thyroid function and lipid levels is important for anyone with thyroid disorders.
Malnutrition and Malabsorption Disorders
Severe malnutrition or conditions that impair nutrient absorption can lead to very low triglyceride levels. When your body doesn't receive adequate calories or fats from food, it has limited raw materials to produce triglycerides. This can occur in several situations:
- Eating disorders such as anorexia nervosa
- Severe dietary restrictions or very low-fat diets
- Chronic illnesses that affect appetite or food intake
- Poverty or food insecurity leading to inadequate nutrition
Malabsorption disorders prevent your intestines from properly absorbing nutrients from food, even when dietary intake is adequate. Conditions like celiac disease, Crohn's disease, chronic pancreatitis, and cystic fibrosis can all lead to fat malabsorption and consequently low triglyceride levels. These conditions often present with additional symptoms such as diarrhea, weight loss, and nutritional deficiencies.
Genetic and Inherited Conditions
Several rare genetic conditions can cause extremely low triglyceride levels. Abetalipoproteinemia is a rare inherited disorder where the body cannot properly absorb and transport fats. People with this condition typically have triglyceride levels near zero and require specialized medical management. Hypobetalipoproteinemia is a related but less severe condition that also results in very low triglyceride and cholesterol levels.
These genetic conditions affect the production of apolipoproteins, which are proteins necessary for packaging and transporting fats in the blood. While rare, these conditions can have serious health implications if not properly managed, including vitamin deficiencies, neurological problems, and vision issues due to impaired absorption of fat-soluble vitamins.
Medications and Medical Treatments
Certain medications can significantly lower triglyceride levels as either a primary effect or side effect. Statins, commonly prescribed for high cholesterol, can reduce triglycerides by 10-30%. More potent triglyceride-lowering medications include:
- Fibrates (fenofibrate, gemfibrozil) - can lower triglycerides by 25-50%
- Omega-3 fatty acid supplements (prescription strength) - can reduce levels by 20-50%
- Niacin (vitamin B3) - can lower triglycerides by 20-40%
- PCSK9 inhibitors - newer medications that can affect lipid levels
In some cases, combination therapy or high doses of these medications can drive triglyceride levels below the normal range. While this is generally not harmful, it's important to work with your healthcare provider to ensure medication dosing is appropriate and to monitor for any adverse effects.
Other Contributing Factors
Liver Disease
The liver plays a central role in triglyceride production and metabolism. Advanced liver disease, including cirrhosis, can impair the liver's ability to produce triglycerides and other lipids. This is because damaged liver cells cannot effectively synthesize the proteins and enzymes needed for fat metabolism. People with severe liver disease often have low levels of multiple blood lipids, not just triglycerides.
Extreme Physical Activity
Elite athletes and individuals who engage in extreme endurance training may have lower than average triglyceride levels. Regular intense exercise increases the body's ability to clear triglycerides from the bloodstream and use them for energy. Marathon runners, professional cyclists, and other endurance athletes often have triglyceride levels at the lower end of the normal range or slightly below.
Autoimmune Conditions
Certain autoimmune conditions can affect lipid metabolism and lead to low triglyceride levels. For example, some people with autoimmune thyroiditis may experience periods of hyperthyroidism before developing hypothyroidism. Additionally, systemic inflammation associated with autoimmune diseases can alter how the body processes and stores fats.
When to Be Concerned About Low Triglycerides
While very low triglycerides are generally less concerning than high levels, they warrant medical attention when accompanied by other symptoms or abnormal lab results. You should consult your healthcare provider if you have:
- Triglyceride levels consistently below 40 mg/dL
- Unexplained weight loss or difficulty maintaining weight
- Chronic diarrhea or signs of malabsorption
- Symptoms of hyperthyroidism (rapid heartbeat, tremors, heat intolerance)
- Family history of lipid disorders
- Other abnormal lipid levels (very low cholesterol)
The clinical significance of low triglycerides depends heavily on the context. In an otherwise healthy person with no symptoms and normal other lab values, mildly low triglycerides may not require treatment. However, when low triglycerides are part of a broader pattern of abnormalities, they can provide important diagnostic clues.
Diagnostic Approach and Testing
If you have very low triglyceride levels, your healthcare provider will likely recommend additional testing to determine the underlying cause. This diagnostic workup may include:
- Complete lipid panel to assess all cholesterol fractions
- Thyroid function tests (TSH, Free T4, Free T3)
- Liver function tests
- Nutritional assessments and vitamin levels
- Tests for malabsorption (if symptoms present)
- Genetic testing (in cases of suspected inherited disorders)
Regular monitoring of your lipid levels and other biomarkers can help identify trends and catch potential problems early. Home testing options now make it easier than ever to track these important health markers without frequent doctor visits.
Treatment and Management Strategies
Treatment for very low triglycerides focuses on addressing the underlying cause rather than the low levels themselves. Management strategies vary depending on the root cause:
For Hyperthyroidism
- Anti-thyroid medications to reduce hormone production
- Radioactive iodine therapy or surgery in severe cases
- Beta-blockers to manage symptoms
- Regular monitoring of thyroid and lipid levels
For Nutritional Causes
- Working with a registered dietitian to ensure adequate caloric intake
- Gradual increase in healthy fats if following an extremely low-fat diet
- Treatment of underlying eating disorders with psychological support
- Nutritional supplementation as needed
For Malabsorption Disorders
- Treatment of the underlying condition (e.g., gluten-free diet for celiac disease)
- Pancreatic enzyme replacement for pancreatic insufficiency
- Fat-soluble vitamin supplementation
- Medium-chain triglyceride (MCT) supplements in some cases
The Bottom Line on Low Triglycerides
Very low triglyceride levels, while less common and generally less dangerous than high levels, can indicate underlying health conditions that require attention. The key is understanding the cause and addressing it appropriately. For most people, low triglycerides in the context of otherwise good health are not a cause for concern. However, when accompanied by other symptoms or laboratory abnormalities, they warrant further investigation.
Regular health monitoring, including periodic lipid panels and other relevant biomarkers, can help you and your healthcare provider identify patterns and make informed decisions about your health. Whether your triglycerides are low due to an overactive metabolism, dietary factors, or medical conditions, understanding the cause is the first step toward appropriate management and optimal health.
References
- Miller M, Stone NJ, Ballantyne C, et al. Triglycerides and cardiovascular disease: a scientific statement from the American Heart Association. Circulation. 2011;123(20):2292-2333.[Link][PubMed][DOI]
- Hegele RA, Ginsberg HN, Chapman MJ, et al. The polygenic nature of hypertriglyceridaemia: implications for definition, diagnosis, and management. Lancet Diabetes Endocrinol. 2014;2(8):655-666.[PubMed][DOI]
- Duntas LH, Brenta G. The effect of thyroid disorders on lipid levels and metabolism. Med Clin North Am. 2012;96(2):269-281.[Link][PubMed][DOI]
- Burnett JR, Hooper AJ. Abetalipoproteinemia and hypobetalipoproteinemia. Clin Lipidol. 2015;10(2):151-159.[DOI]
- Nordestgaard BG, Varbo A. Triglycerides and cardiovascular disease. Lancet. 2014;384(9943):626-635.[PubMed][DOI]
- Berglund L, Brunzell JD, Goldberg AC, et al. Evaluation and treatment of hypertriglyceridemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2012;97(9):2969-2989.[Link][PubMed][DOI]
Frequently Asked Questions
How can I test my triglycerides at home?
You can test your triglycerides at home with SiPhox Health's Core Health Program or Heart & Metabolic Program. Both CLIA-certified programs include triglyceride testing along with other essential lipid markers, providing lab-quality results from the comfort of your home.
What is considered a dangerously low triglyceride level?
Triglyceride levels below 40 mg/dL are considered very low, with some labs using 35 mg/dL as the cutoff. Levels approaching zero are extremely rare and usually indicate genetic conditions like abetalipoproteinemia. While low triglycerides alone are rarely dangerous, they may signal underlying health issues requiring evaluation.
Can diet cause very low triglycerides?
Yes, extremely restrictive diets, particularly those very low in fat or calories, can cause low triglyceride levels. Eating disorders like anorexia nervosa often result in very low triglycerides due to inadequate nutrition. A balanced diet with healthy fats is important for maintaining normal triglyceride levels.
Should I be worried if my triglycerides are low but I feel fine?
If you have no symptoms and your other lab values are normal, mildly low triglycerides (40-50 mg/dL) are usually not concerning. However, consistently very low levels (under 40 mg/dL) warrant discussion with your healthcare provider to rule out underlying conditions like hyperthyroidism or malabsorption disorders.
How often should I check my triglyceride levels?
For most adults, checking triglycerides annually as part of a lipid panel is sufficient. However, if you have very low levels or underlying conditions affecting your triglycerides, your doctor may recommend testing every 3-6 months to monitor trends and treatment effectiveness.
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