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13 Causes of High Triglycerides + Normal Levels

Written by Biljana Novkovic, PhD | Last updated:
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Biljana Novkovic, PhD | Last updated:

High levels of triglycerides can increase your risk of obesity, heart disease, diabetes, and other chronic health conditions. Read on to find out if your levels are within the normal range and to learn which factors and conditions can increase triglyceride levels.

What Are Triglycerides?

Triglycerides are the scientific term for fats, including the fats you eat in your diet and the fat that is stored in your body. They are formed from a combination of a compound called glycerol and three fatty acids [1].

Dietary triglycerides are digested and absorbed in the small intestine. They are then packaged together with cholesterol and proteins in particles called chylomicrons, which carry triglycerides from the gut to other tissues [2, 3].

The liver can also produce triglycerides from sugars and other fats. It does so when you eat a lot of carbs or more calories than your body needs [4, 5, 6].

Triglycerides can be stored in fat tissue, or can be used as energy [2].

For example, the body can release stored fats into the bloodstream as fatty acids when you don’t eat for a prolonged time. These fatty acids travel back to the liver, which transforms them into triglyceride-containing very-low-density lipoproteins (VLDL) that are returned into the blood [7].

On the other hand, your body stores more triglycerides when you overeat or have an unhealthy diet [8].

Burning triglycerides for fuel requires a special enzyme (lipoprotein lipase), which is found in the muscles [1].

Triglycerides are fats you get through diet, store in fat tissue, and burn as fuel when needed. The liver can make triglycerides from sugar and other fats.

Triglycerides Normal Range

A blood test can measure circulating triglyceride levels. This test requires overnight fasting for accurate results, as triglycerides normally spike one to four hours after a meal [4].

Triglyceride levels are classified as follows [3, 9, 10]:

  • Optimal: Less than 90 mg/dL (1 mmol/L)
  • Normal: Less than 150 mg/dL (1.7 mmol/L)
  • Borderline high: 150 to 200 mg/dL (1.7 to 2.3 mmol/L)
  • High: 200 to 500 mg/dL (2.3 to 5.6 mmol/L)
  • Very high: 500 mg/dL or above (5.6 mmol/L)

People of African origin tend to have lower triglyceride levels than whites [11, 12].

Women tend to have lower levels than men [13].

Triglyceride levels normally rise significantly (as much as threefold) during the third trimester of pregnancy, before eventually returning to normal [14].

Causes of High Triglycerides

A study that looked at 5.6k people who participated in a National Health and Nutrition Examination Survey found that about one-third of US adults had high triglyceride levels (above 150 mg/dL) [15].

A similar study of 5.6k people found that only about 2% of adults experienced extremely high levels (500 to 2,000 mg/dL), the leading cause of pancreas inflammation in the US [16].

High triglyceride levels can be caused by lifestyle and dietary factors, genetics, and other diseases [17].

On a mechanistic level, triglycerides will rise too much if [18]:

  • Your liver is producing too much triglyceride-dense VLDL cholesterol
  • Your diet is excessive and unhealthy
  • You have low lipoprotein lipase activity, which is the enzyme that breaks down triglycerides

All the potential causes outlined below affect one or more of these conditions.

Causes listed below are commonly associated with high triglycerides. Work with your doctor or another health care professional to get an accurate diagnosis.

1) Diets High In Calories, Carbs, and Fats

Triglyceride levels increase with a positive energy-intake balance (overeating). In other words, when you eat more than your body needs, the surplus is transformed into fat, including triglycerides. It’s easier to overeat when your diet is high in calories and contains lots of carbs and saturated fats [14, 6].

Low-fat, high-carbohydrate diets are among the most common causes of high triglycerides. But wait – we said that high-fat diets are bad, so doesn’t that mean a low-fat diet should be beneficial? Not quite [6].

Saturated, unhealthy fats are bad. But your body needs healthy fats – such as those found in olive oil and fish oil – to keep your triglyceride levels normal and to maintain your overall health. If you don’t get enough dietary fats, your body will revert to transforming the sugars you consume into fats [6, 19, 20, 21].

This goes against the popular but unfounded belief that your body won’t store fat as long as you don’t eat fats. In truth, high-carbohydrate diets can be much worse than high-fat diets for your triglyceride levels. Many scientists advocate that high-carb, low-fat diets likely also contributed to the obesity epidemic in America over the past few decades [6, 19, 20, 21].

In a small-scale interventional study, 5 people with high triglyceride levels and 6 people with normal levels were put either on a regular or on a low-fat, high-carb diet. The results were drastic: the low-fat, high-carb diet increased triglycerides by 60% in both groups! It also reduced the clearance of triglyceride-dense VLDL by almost 40% [6].

Eating more calories than you need, and especially low-fat, high-carb diets increase triglyceride levels.

2) Obesity

Directly tied to high-calorie diets and overeating, obesity is often associated with high triglyceride levels. People with obesity also often have high “bad” LDL cholesterol and low “good” HDL cholesterol, which burdens blood vessels. This combination of factors increases chronic inflammation and the risk of heart disease and diabetes [22].

Obesity often leads to insulin resistance, which is when tissues stop responding to insulin released from the pancreas. As a result, insulin can’t signal tissues to burn fat and glucose can’t enter cells to be used as energy. The liver tries to compensate by storing more fatty acids from dietary sources and producing more VLDL cholesterol, which further worsens the situation [22].

Initial studies suggest that obesity might turn on fat-increasing genes. In a meta-analysis of nearly 10k Swedish adults, body fat increased the influence of the triglyceride-increasing gene variants, especially in women. Similar results were found in a Danish study with over 8.5k adults [23, 24].

Obesity increases triglycerides by increasing insulin resistance and by increasing the influence of triglyceride-increasing gene variants.

3) Inactivity

Being physically inactive and leading a predominantly sedentary lifestyle is associated with higher triglyceride levels [25, 26, 27]. The less you exercise, the less food (energy) you need, and therefore you are more likely to eat more calories than you need.

4) Smoking

Several studies have found a link between smoking and higher triglyceride levels [28, 29, 30].

Among 191 women, nonsmokers had 40% lower triglyceride levels than smokers on average. Smokers also had slightly higher total cholesterol and lower HDL cholesterol [28].

5) Heavy Drinking

Heavy drinkers have higher triglyceride levels, and they are also at an increased risk of heart disease, alcoholic fatty liver disease, and pancreas inflammation. Excessive drinking increases triglycerides by forcing the liver to release more VLDL, reducing fat-burning, and increasing fat storage in the liver [31].

Physical inactivity, smoking, and heavy drinking can all increase triglyceride blood levels.

6) Type 2 Diabetes

In people with type 2 diabetes tissues stop responding to insulin. This means that glucose can’t get inside of cells and cells need another energy source. As a result, the liver makes large amounts of triglyceride-containing VLDL [14].

7) Liver Disease

Liver disease such as non-alcoholic fatty liver disease (NAFLD) and cirrhosis (liver scarring) due to alcohol increase triglyceride levels [32, 33].

People with nonalcoholic fatty liver disease produce more and remove less triglycerides, due to a high-fat diet or insulin resistance, faulty fatty acid breakdown, or defective VLDL production [7, 1, 34, 35, 36].

8) Inflammation, Infection, and Autoimmunity

In some cases, high triglycerides may be caused by inflammation and infection.

People with infections and chronic inflammatory and autoimmune diseases – such as rheumatoid arthritis, lupus, and psoriasis – often have high triglycerides and low HDL. These disease-triggered changes initially serve to dampen inflammation or fight infection, but they increase the risk of heart disease in the long run [37, 14].

For example, untreated gum disease (periodontitis) increases blood triglycerides. People with chronic gum inflammation are continually exposed to bacteria, which disrupt immune and lipid balance in the body [38].

Type 2 diabetes, liver disease, infections, chronic inflammation, and autoimmune disease can all increase triglyceride levels

9) Vitamin D Deficiency

Vitamin D has many benefits, and supporting normal triglyceride levels is one of them [39, 40, 41].

According to a study of almost 3.8k people, vitamin D deficiency is associated with higher triglyceride levels [41]. Similar results were found in another study of 1.5 people and a study of 149 children [39, 40].

10) An Underactive Thyroid (Hypothyroidism)

An underactive thyroid (hypothyroidism) increases triglyceride levels by interfering with cholesterol production in the body. As soon as thyroid hormones normalize, triglycerides go back to normal. Even people with mild hypothyroidism and borderline normal thyroid-stimulating hormone (TSH) levels are more likely to have high triglycerides, high LDL, and low HDL [42].

11) Kidney Disease

People with chronic kidney disease are already at an increased risk of heart disease. They also often suffer from high triglyceride levels (but normal cholesterol levels), which further increase the risk of heart complications. Triglycerides start to increase early on in the disease and reach a maximum in the end stages [43].

People with low vitamin D levels, underactive thyroid, or kidney disease are more likely to have high triglycerides, which puts them at an increased risk of heart disease.

12) Rare Genetic Disorders

Some rare genetic disorders can decrease the clearance of triglycerides. These include familial chylomicronemia, primary mixed hyperlipidemia, and familial dysbetalipoproteinemia [44].

13) Certain Medications

The following medications may increase triglycerides:

  • Corticosteroids [14]
  • Estrogens [14, 45]
  • Water pills (diuretics) [14, 45]
  • Beta-blockers [14, 45]
  • Antiretrovirals [14]
  • Retinoids [45]
  • Some antipsychotics [45]

Triglycerides & Genes

Some genetic variants may contribute to higher triglycerides, including [17, 9, 46, 47, 48, 49]:

In a 9-year study on over 9,000 Europeans, people with higher triglyceride gene scores had a greater increase in their triglyceride levels compared to those with lower triglyceride gene scores [50].

In 3,474 non-diabetic adults, increased blood triglyceride levels were associated with 39 genetic variants over the course of a 5-year follow-up period [51].

A case-control study of 569 obese and 194 healthy Chinese children and adolescents revealed that genetic variations in the APOA5 gene (rs662799 and rs651821) may dictate how susceptible a person is to obesity, which is linked with triglyceride buildup [52].

Certain genetic variants have been associated with high triglyceride levels, but more research is needed to determine their relevance.


High triglyceride levels do not cause symptoms directly, and individuals will only show symptoms related to the cause of high triglyceride levels, such as hypothyroidism or liver disease.

Extremely high triglycerides (>400 mg/dL or 4.5 mmol/L) may cause yellowish patches on the skin (xanthomas) [53].

Your symptoms will depend on the underlying condition. High triglycerides don’t usually cause any symptoms.

Health Effects of High Triglycerides

1) Heart Disease

High blood triglycerides increase the risk of heart disease even when cholesterol levels are within the normal range. Many studies on diverse populations with over 60,000 people in total have confirmed this [54, 55, 56, 57, 58, 59, 60]

2) Diabetes

Though insulin resistance can increase triglyceride levels, the opposite is also true: increased blood triglycerides can cause insulin resistance [61, 62, 63, 64].

A 10-year study in 14k initially healthy men suggests that high blood triglycerides increase the risk of type 2 diabetes, independent of other risk factors (obesity, eating habits, smoking, cholesterol, diabetes, and blood pressure) [65].

In another 12-year long study of 5k adults, each 10 mg/dL rise in blood triglyceride increased the risk of type 2 diabetes by 4% [66].

Interestingly, research suggests that people who have high triglycerides due to specific genetic variants (rs2954029, rs714052, rs7557067, rs17216525, rs10889353, rs7679, rs7819412, rs328, rs3135506, rs662799) may not be at a higher risk of type 2 diabetes [67].

This would mean that triglyceride levels are likely a proxy for how healthy i.e. how high in carbs a person’s diet is.

High triglyceride levels have been associated with a higher risk of diabetes

3) Cancer

In studies of over half a million people in total, high blood triglycerides were associated with a higher risk of lung, rectal, colon, cervical, ovarian, skin, endometrial, and thyroid cancer, but with a lower risk of prostate cancer and non-Hodgkin’s lymphoma (cancer of the lymphocytes, a type of white blood cell) [68, 68, 69, 69].

However, in a meta-analysis of over a million healthy people and cancer patients, increased triglyceride levels were not associated with the risk of prostate or breast cancer [70].

Then again, studies focusing on breast cancer have reported a positive association between high blood triglycerides and breast cancer risk, whereas one showed an inverse association [71, 72, 73, 74].

Also, some studies suggest that high levels don’t reduce prostate cancer risk, or possibly even increase it [75, 76, 77, 78].

Many factors beyond triglyceride levels affect cancer risk and outcomes. More research is needed to tease apart all the influences.

High triglyceride levels may increase the risk of some cancers and lower the risk of others, but the research so far remains inconclusive.

4) Kidney Disease

In 25,641 patients with late-stage chronic kidney disease, high blood triglyceride levels (equal to or above 200 mg/dL) increased the risk of death among patients younger than 65 [79].

People with kidney disease and increased triglycerides may have a poorer prognosis.

5) Pancreas Inflammation (Pancreatitis)

High blood triglycerides may cause chronic pancreatitis, whereas extremely high levels (above 1,000 mg/dL) can lead to acute pancreatitis [80, 81, 82, 83, 84, 85].

In 582 patients with acute pancreatitis, blood triglyceride levels of more than 2.26 mmol/L increased the risk of [86]:

  • Mental disturbances
  • Death of pancreatic tissue (pancreatic necrosis)
  • Acute respiratory distress syndrome (RDS)
  • Systemic inflammatory response syndrome (SIRS)
  • Acute kidney injury
High triglyceride levels can cause pancreas inflammation and increase the risk of health complications that can occur as a result.

Learn More


Triglycerides are fats that you absorb from food or create in the liver, often from sugars. High triglyceride levels increase the risk of heart disease and diabetes. Built-up triglycerides can damage and clog blood vessels, reduce fat burning in cells, and increase fat storage in the liver. High levels are often accompanied by an increase in LDL cholesterol and a drop in HDL cholesterol, a detrimental combination for your heart and overall health. Your diet and weight have a huge impact on your levels. Diets high in calories, high-carbohydrate, low-fat diets, and obesity increase triglycerides. Vitamin D deficiency, smoking, an underactive thyroid, inflammation, genetics, and certain medications and diseases can also raise your levels.

About the Author

Biljana Novkovic

Biljana received her PhD from Hokkaido University.
Before joining SelfHacked, she was a research scientist with extensive field and laboratory experience. She spent 4 years reviewing the scientific literature on supplements, lab tests and other areas of health sciences. She is passionate about releasing the most accurate science and health information available on topics, and she's meticulous when writing and reviewing articles to make sure the science is sound. She believes that SelfHacked has the best science that is also layperson-friendly on the web.


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