Triglycerides are an important source of energy, but high triglyceride levels increase the risk of cardiovascular diseases, some of which can cause fatigue.

Triglycerides are a type of fat, or “lipid,” that circulate in the blood. They derive from fats in the foods a person eats and from excess calories that the body stores in fat cells.

High triglycerides do not directly cause fatigue, but a diet high in triglycerides raises a person’s risk of serious cardiovascular conditions.

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However, uncontrolled high blood triglyceride levels can increase a person’s risk of coronary heart disease (CHD), a condition in which the blood vessels supplying the heart become narrowed and blocked.

Over time, CHD can lead to other cardiovascular diseases that may cause tiredness and fatigue, such as heart failure and stroke.

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Heart failure and fatigue

As the American Heart Association (AHA)Trusted Source explains, heart failure is a condition in which the heart cannot pump enough blood to meet the body’s blood and oxygen requirements.

To compensate, the body diverts blood away from less vital tissues, such as the muscles in the limbs, and sends it to vital organs, including the heart and brain.

This may cause symptoms of tiredness and fatigue, especially after eating and during physical exertion.

Stroke and fatigue

According to a 2019 reviewTrusted Source, up to 40% of people who have had a stroke report fatigue as either their worst or one of their worst symptoms.

The American Stroke Association (ASA)Trusted Source, notes that most people with post-stroke fatigue report that the symptom occurs without warning and interferes with their ability to carry out daily activities.

Factors that may cause or contribute to post-stroke fatigue include:

  • brain lesions
  • post-stroke inflammation
  • post-stroke hormone changes
  • residual neurological issues
  • reduced physical activity

As the NHLBITrusted Source explains, triglyceride levels in adults will fall into one of the following categories:

  • Healthy: below 150 milligrams per deciliter (mg/dL)
  • Borderline high: between 150 mg/dL and 199 mg/dL
  • High: between 200 mg/dL and 499 mg/dL
  • Very high: above 500 mg/dL

A doctor will diagnose high blood triglycerides if a person’s fasting blood triglyceride levels regularly reach or exceed 150 milligrams mg/dLTrusted Source.

As the NHLBITrusted Source explains, a diet high in triglycerides can increase a person’s risk of a range of health issues, including:

  • heart complications
  • acute pancreatitis
  • lipemia retinalis, which is a condition that affects blood vessels in the eyes
  • skin damage on the back, chest, arms, and legs

According to the NHLBITrusted Source, extremely high blood triglyceride levels exceeding 1,500 mg/dL can lead to a condition called multifactorial chylomicronemia syndrome (MCS).

This is where the body stops breaking down fats. MCS can lead to potentially life threatening acute pancreatitis and swelling of the liver and spleen.

Symptoms of MCS include:

As the NHLBITrusted Source explains, triglycerides come from fats in foods, such as oils, and dairy products like butter and cheese.

Importantly, triglycerides also come from extra calories that the body does not need to use straight away. The body stores these unused calories as triglycerides in fat cells.

The National Lipid Association (NLA) notes that the following foods can increase triglyceride levels:

Below are some answers to frequently asked questions about high triglyceride levels.

What organ is affected by high triglycerides?

High blood triglycerides can affect various organs in the body, most notably the heart and brain.

This is because high blood triglycerides can cause coronary artery disease, which can in turn lead to heart disease and stroke.

Can high triglycerides cause brain fog?

As a 2023 review explains, “brain fog” is a term that people generally use to describe one or more of the following:

A 2021 reviewTrusted Source found an association between high triglyceride levels and cognitive impairment.

One possible reason for this is that high blood triglycerides can cause metabolic issues, which then increase a person’s risk of vascular dementia.

This type of dementia occursTrusted Source as a result of impaired blood flow to the brain.

Can you recover from high triglycerides?

A person with high blood triglycerides can lower their triglyceride levels so that they fall within a healthy range.

As the NLA explains, the best way to do this is to limit intake of fatty foods and foods that can increase triglyceride levels, such as:

  • starchy foods
  • foods and beverages high in natural or added sugars
  • alcohol

Triglycerides are fats in the blood that provide energy, but high levels can increase the risk of cardiovascular diseases, which may cause fatigue.

Extremely high levels can lead to serious conditions like multifactorial chylomicronemia syndrome (MCS). Reducing fatty, sugary, and starchy foods, along with getting regular exercise, can help lower triglyceride levels.