What causes high triglycerides, and what the number on your panel actually means

Triglycerides are the number on a lipid panel that gets the least attention, because the public conversation about "good" and "bad" cholesterol crowds it out. But it is the number most directly tied to what you eat, drink and weigh — and, at the extreme high end, the one that can put you in hospital. Here is what the value measures, what pushes it up, and when it stops being a statistical risk marker and becomes an emergency.

What the number measures

Triglycerides are the main form in which the body stores and transports fat, and they are measured in milligrams per deciliter of blood [s3]. The commonly used adult categories are: healthy is less than 150 mg/dL; borderline high is 150 to 199 mg/dL; high is 200 to 499 mg/dL; and very high is 500 mg/dL and higher [s3]. A level of 150 mg/dL or higher is also one of the criteria used to define metabolic syndrome [s2]. The test is usually run as part of the same fasting blood draw that reports your cholesterol, and the fasting matters, because a recent meal can transiently raise the value [s3].

What actually raises it

Most of the common drivers of a high triglyceride level are things about daily life rather than anything exotic. MedlinePlus lists the factors that can raise triglycerides as: regularly eating more calories than you burn off, especially a lot of sugar; being overweight or having obesity; cigarette smoking; excessive alcohol use; certain medicines; some genetic disorders; thyroid diseases; poorly controlled type 2 diabetes; and liver or kidney diseases [s2].

That list is the reason the clinical guidance treats a raised triglyceride level as a prompt to look for a cause rather than as a diagnosis in itself. The Endocrine Society's clinical practice guideline recommends that patients with hypertriglyceridemia be evaluated for secondary causes of high blood lipids, and that people with a primary (inherited) form be assessed for a family history of lipid disorders and cardiovascular disease [s1]. In practice that means an out-of-range result often points back to weight, alcohol intake, blood-sugar control or an underactive thyroid before it points to a lipid problem that needs its own drug.

Why the level matters

A triglyceride level above 150 mg/dL is associated with a higher risk of heart disease and stroke, and it travels in company — high triglycerides frequently accompany the cluster of blood-pressure, waist-circumference and blood-sugar findings that make up metabolic syndrome [s2]. That clustering is part of why triglycerides on their own are a slippery thing to interpret: the number is often a readout of the metabolic state around it as much as an independent cause of harm.

At the top of the range the concern changes character entirely. The Endocrine Society guideline draws a line between mild-to-moderate hypertriglyceridemia — triglycerides of 150 to 999 mg/dL, which it frames as useful mainly for evaluating cardiovascular risk — and severe and very severe hypertriglyceridemia, triglycerides above 1000 mg/dL, which it says should be considered a risk for pancreatitis [s1]. Pancreatitis is acute inflammation of the pancreas; MedlinePlus similarly notes that very high triglyceride levels increase the risk of sudden pancreatitis [s3]. That is the threshold at which a lipid number becomes a reason to seek care promptly rather than at the next routine visit.

What lowers it

Because so many of the causes are lifestyle-linked, so is much of the response. The Endocrine Society guideline states that the initial treatment for hypertriglyceridemia should be lifestyle therapy — diet modification and, where appropriate, a combination of diet and drug therapy [s1]. MedlinePlus describes the same first step in plainer terms: controlling weight, regular physical activity, not smoking, and limiting sugar and refined carbohydrates [s2]. Only at the severe end does the guideline reach for medication as the front-line move, recommending a fibrate as the first-choice drug in patients with severe or very severe hypertriglyceridemia — the group whose immediate risk is pancreatitis rather than long-term heart disease [s1].

What this does and doesn't tell you

None of the above is a personal treatment plan. Whether a given triglyceride number warrants a change in diet, a search for a thyroid or blood-sugar problem, or a medication depends on the whole clinical picture — the rest of the lipid panel, blood pressure, weight, family history and other risk factors — which is exactly why guidelines set treatment on combined risk rather than on this one value. What the evidence does settle is the shape of the thing: a triglyceride number is mostly a mirror of metabolism and habit, most of its common causes are modifiable, and a reading in the four-figure range is a different and more urgent problem than a borderline one.

If your triglycerides come back high, that is a conversation to have with a clinician — and a very high result, in particular, is not one to sit on.

Sources

• Evaluation and Treatment of Hypertriglyceridemia: An Endocrine Society Clinical Practice Guideline — The Journal of Clinical Endocrinology & Metabolism, 2012-09-01
• Triglycerides — MedlinePlus, National Library of Medicine
• Triglycerides Test — MedlinePlus, National Library of Medicine