What are triglycerides?

Triglycerides are a combination of three fatty acids or fats (i.e. saturated fat, unsaturated fat or both) combined with glycerol, a form of glucose.

Triglycerides are our main source of energy and as they are so important we have two supplies – one supply from our diet and one supply made in the body by our liver.

When we eat foods containing triglycerides, such as meat, dairy produce, cooking oils and fats, they are absorbed by our intestines and then packaged into particles called lipoproteins, (known as chylomicrons) which carry the triglycerides to our tissues to be used for energy straight away or for storage to be used when they are needed.

The body also makes its own supply of triglycerides in the liver. This form is carried in a different type of lipoprotein known as VLDL.

When are triglycerides measured?

Triglyceride levels should be measured at the same time as cholesterol as they can also contribute to our risk of developing heart and circulatory disease. The triglyceride test measures the triglycerides carried in the two main carrying particles (chylomicrons and VLDL).  National guidelines in the UK no longer recommend the need for a fasting blood test and HEART UK experts state that we should aim for a non fasting triglyceride level below 2.3mmol/L.

If your doctor has asked you to fast for a test (usually for 10-14 hours) then this level should be below 1.7mmol/L.  This "fasting test" number is lower because in the fasting test only the triglycerides made by the liver and carried in the VLDLs will be measured.

As you have not eaten then there will be no chylomicrons present in your blood.

 When do raised triglycerides occur?

Triglycerides can be raised due to what doctors refer to as "primary" and "secondary" causes explained below.  Some people can have a combination of both.  

Primary refers to an inherited, genetic condition which causes raised triglyceride levels.  Secondary refers to the many other influences on triglyceride levels which includes our diet and lifestyle, certain medical conditions, medications so it is very important that your doctors should investigate all these potential causes.  High triglyceride levels are known to contribute to our risk of developing heart and circulatory disease, and very high triglyceride levels can cause serious medical conditions such as pancreatitis.

Primary causes include inherited conditions such as familial hypertriglyceridaemia where trigylcerides are raised; Familial Combined Hyperlipidaemia (FCH) and type 3 hyperlipidaemia where both triglycerides and cholesterol are raised, and the rarer condition Familial Chylomicronaemia Syndrome (FCS) where triglyceride levels are extremely high. You can find out more about these conditions from our section on cholesterol conditions

Secondary causes include a sedentary lifestyle/lack of physical activity, unhealthy diet,  particularly diets high in saturated fats, added sugars. This also includes alcohol where some people may be very sensitive to even small amounts that can significantly increase their triglyceride levels.

Medical conditions that can affect triglyceride levels include kidney disease, non alcoholic fatty liver disease, gout, pregnancy and an underactive thyroid. Those with conditions such as obesity, type 2 diabetes and metabolic syndrome usually have an unhealthy pattern of high triglycerides along with low HDL cholesterol (the good protective particle).  In type 2 diabetes this pattern is usually accompanied by the smaller "atherogenic" LDL cholesterol particles (bad cholesterol). Medications which can affect triglyceride levels include some diuretics, steroids, oral oestrogen therapy, retinoids and retrovirals.

Recommendations for lowering triglycerides

As with all lipid conditions, diet and lifestyle measures are the cornerstones of treatment. Triglycerides tend to be very responsive to changes in diet and health behaviours. 

  • maintain a healthy body weight. A combination of regular exercise and loss of excess weight can often result in significant lowering of triglyceride levels.
  • follow a healthy eating plan which is low in saturated fat, replaced with unsaturated fats, such as oily fish. Cut down on added sugars in food and drinks; drink alcohol in moderation, if at all. In susceptible people, even small amounts of alcohol can significantly raise triglycerides.

If lifestyle measures are ineffective in lowering triglyceride levels or you have been diagnosed with a genetic condition then medication may be needed. Statins are usually the first line of treatment for those who cannot reduce their triglyceride levels by diet and lifestyle alone. Cholesterol specialists may also prescribe medications such as fibrates and omega 3 acid ethyl esters.

 Please see our medication fact sheet for more information.