Genetics Northern California

Familial Hypertriglyceridemia

Triglycerides are the main form of fat storage in the body and are a necessary source of energy. Familial hypertriglyceridemia is a genetic condition that causes the triglyceride levels in the blood to get too high. This relatively common condition affects about 1 in 500 people in the United States.  Familial hypertriglyceridemia is typically inherited in a dominant manner. This means there is 50% chance for a parent to pass this condition on to any child.

It is important to note that many people with high triglyceride levels do not have familial hypertriglyceridemia. Some common reasons for high triglycerides include:

• Being overweight or obese
• Drinking too much alcohol
• Diabetes
• Thyroid problems
• Taking estrogen
• Eating too much fat or refined carbohydrates
• Some medications (such as Accutane)
• Kidney problems

For families who have an inherited (genetic) cause of high triglycerides, there are two types of familial hypertriglyceridemia. Some families make too much of a substance known as very low density lipoprotein or VLDL. In other families, VLDL is made in normal amounts, but a genetic difference makes the body unable to break it down and clear it from the blood.  Either genetic condition causes a high level of VLDL,  which leads to a high level of triglycerides in the blood.

Why are high levels of triglycerides a risk factor for cardiovascular disease 
The reason high levels of triglycerides are a risk factor for cardiovascular (heart and blood vessel) disease is not completely understood. The triglyceride level in the blood is related to two other lipoproteins in the body, high-density lipoprotein (HDL), and small, dense, low-density lipoprotein (LDL) – you will see measurements of these fats in a standard “lipid panel” blood test. As the ratio of triglycerides to HDL levels increases, so does the chance of having small dense LDLs. Both low levels of HDL (this is the “good” cholesterol that should be high) and the presence of small dense LDLs (the “bad” cholesterol that should be low) are known risk factors for CVD. Small dense LDL can increase the risk for heart disease up to 3-fold. They are harder for the body to break down, so they stay in the blood for a longer time, where they can cause problems. Small dense LDLs are more susceptible to damage and are taken up by white blood cells, known as macrophages. This leads to production of atherogenic (blood vessel plaque-forming) foam cells. The foam cells trigger inflammation in the blood vessel walls, which can lead to blockage of blood flow and a heart attack or stroke.

High triglyceride levels can also increase the risk of blood clots (thrombosis), which can also lead to a heart attack or stroke. If not treated, high triglycerides can lead to fatty liver disease which causes changes in the liver and can eventually result in permanent damage and liver failure.

A fasting triglyceride blood level above 100 (in children) or above 200 (in adults) indicates a possible familial hypertriglyceridemia.
Reference Range-Triglycerides
Why test triglycerides levels?   
A triglyceride level is usually part of routine cholesterol screening. Monitoring triglycerides in a person with familial hypertriglyceridemia is important for appropriate health management. Additionally, there is an increased risk of developing pancreatitis when triglycerides are consistently above 500. Pancreatitis is an inflammation of the pancreas that may cause severe abdominal pain and other symptoms. When triglycerides are continually elevated there is also a concern of developing fatty liver and xanthomas (fat deposits under the skin). Consistently high levels of triglycerides may also indicate diabetes (abnormal handling of sugar by the body) is present or is developing.

FMT05d036Lifestyle changes are the best therapy for high triglycerides. The following changes will help reduce triglycerides: 

  • If overweight, reduce calories to lose weight. This includes all sources of calories from fats, proteins, carbohydrates and alcohol.

  • Focus on plant foods: The Plant Based Diet booklet

  • Choose complex higher fiber foods over refined carbohydrate foods
      - Fiber Facts - Information sheet
      - Whole Grains and Fiber - American Heart Association webpage

  • Be physically active. Engage in some form of physical activity for at least 30 minutes a day most days of the week.

Triglycerides can increase because of too much dietary fat or carbohydrate, especially simple, or refined carbohydrate and sugar. Reduce the amount of all simple carbohydrates such as:

·         Concentrated sweets (sugar, honey, molasses, jams, jellies, and candies)

·         Any food containing high fructose corn syrup (such as: some sweetened breakfast cereals, flavored yogurt, reduced fat salad dressings, and soda) Check food labels for high fructose corn syrup

·         Desserts (for example: pies, cakes, cookies, candy, doughnuts, ice cream, frozen yogurt, and sweetened gelatin)

·         Sweetened beverages (fruit juices, fruit drinks, fruit punches, regular sodas, carbonated pop, smoothies, sports drinks, sweetened coffee drinks, mocha, and chocolate drinks)

·         Other sweetened foods (high sugar cereals, flavored yogurts, and sports or energy bars)

·         Alcohol (beer, wine, hard liquor, liqueurs)

People with high triglycerides may benefit from eating more fish; especially fish high in omega-3 fatty acids, like herring, sardines, albacore tuna and salmon. Fish oil supplements can also be taken, if recommended by your health care provider. The therapeutic dose is 1 to 3 grams of EPA/DHA per day.  The levels of EPA/DHA in fish oils vary quite a bit among brands, so check the label. Purchase fish oil capsules that have been molecularly distilled to remove contaminants. Check with your health care provider to see if omega-3 fatty acids might be beneficial.

For severely elevated triglycerides (above 800), it is best to work with a registered dietitian. Reduce fat to less than 10 grams per day and eliminate ALL simple or refined carbohydrate.  Eat only small amounts of lean protein (chicken, seafood, etc) and increase foods high in soluble fiber. Include more non-starchy vegetables are fewer grain-based carbohydrates.

When lifestyle changes are not enough to lower triglyceride levels, medications may be needed. The most common medications used are fibrates. 

Created by: Suzanne Kordesh, MPH, RD  
Reviewed by: Dr. Leslie Manace Brenman, MD MPhil, Sub-Chief, Kaiser Permanente Northern California Genetics
Last Reviewed: January 2022