Triglycerides are a type of blood fat. They are our main source of energy and are essential for good health. But if you have too much in your blood, this can raise the risk of heart disease.
High triglycerides are known to contribute to the risk of heart disease and other diseases of the heart and blood vessels, and very high triglyceride levels can cause serious medical conditions such as pancreatitis.
What are triglycerides?
Triglycerides are a combination of:
- three fatty acids (i.e. saturated fat, unsaturated fat or both – these are the building blocks of fats)
- glycerol, a form of glucose (a simple sugar).
Triglycerides are our main source of energy and, as they are so important, we have two supplies: one from our diet and one made by the liver.
How do triglycerides get into the blood?
When we eat foods containing triglycerides, such as meat, dairy products, cooking oils and fats, they are absorbed by our intestines and packaged into parcels of fats and protein called chylomicrons (a type of lipoprotein). These carry the triglycerides in the blood stream to our tissues to be used for energy straight away, or stored for later.
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 cholesterol.
Finding out your triglycerides levels
Triglycerides are measured with a simple blood test. Triglyceride levels should be measured when you have a cholesterol test as they can also contribute to your risk of developing heart disease, and other disease of the heart and blood vessels.
The triglyceride test measures the triglycerides carried in chylomicrons and VLDL cholesterol. National guidelines in the UK no longer recommend a fasting blood test (where you fast for a period of time before your blood test).
What should your triglyceride levels be?
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 your triglyceride level should be below 1.7mmol/L. This "fasting test" number is lower because only the triglycerides made by the liver and carried in the VLDL cholesterol will be measured – not the triglycerides you get from food. As you have not eaten, there will be no chylomicrons present in your blood.
Triglycerides can be raised due to what doctors refer to as 'primary' and 'secondary' causes, explained below. Some people have a combination of both.
It is very important that your doctors investigates all these potential causes so that you can start treatment.
Primary causes of raised triglycerides
'Primary' refers to inherited (genetic) conditions which cause raised triglyceride levels.
- familial hypertriglyceridaemia, where trigylcerides are raised
- familial combined hyperlipidaemia (FCH), where both triglycerides and cholesterol are raised
- type 3 hyperlipidaemia, where both triglycerides and cholesterol are raised
- familial chylomicronaemia syndrome (FCS), a rarer condition where triglyceride levels are extremely high.
Secondary causes of raised triglycerides
'Secondary' refers to the many other things that can influence triglyceride levels, including diet and lifestyle, certain medical conditions and medications.
Lifestyle causes include:
- a sedentary lifestyle (lack of physical activity)
- an unhealthy diet, particularly diets high in saturated fats and added sugars
- alcohol – some people may be very sensitive even to small amounts of alcohol, and these can significantly raise their triglyceride levels.
Medical conditions include:
- kidney disease
- non alcoholic fatty liver disease
- an under-active thyroid.
- Some diuretics
- oral (tablets) oestrogen therapy
High triglycerides and low HDL – an unhealthy pattern of blood fats
People with high triglyceride levels often have low HDL cholesterol (good cholesterol) as well. This is an unhealthy combination of blood fats that's often linked with premature heart disease.
It can be inherited, and often occurs in people who:
- are very overweight, especially if they carry their weight around their middle
- have Type 2 diabetes
- have metabolic syndrome.
People with Type 2 diabetes usually have high LDL cholesterol (bad cholesterol) as well. This type of cholesterol is 'atherogenic', meaning it clogs up the arteries, leading to heart attacks and strokes.
As with many conditions that raise blood fats, diet and lifestyle changes are the cornerstones of treatment. Triglycerides tend to be very responsive to changes in diet and lifestyle.
Eat a healthy diet
- Cut down on saturated fats and replace these with unsaturated fats such as oily fish.
- Cut down on added sugars in food and drinks
- Drink alcohol in moderation, if at all.
If changes to your lifestyle don't lower your triglyceride levels enough or you have been diagnosed with a genetic condition, then you may need medication.
Statins are usually the first line of treatment. Cholesterol specialists may also prescribe medications such as fibrates and omega 3 acid ethyl esters.