High cholesterol is one of the most important risk factors for cardiovascular disease (CVD), which includes conditions such as heart attacks and strokes. Find out about what blood fats are, what they should be, and what you can do to improve them.

What are cholesterol and triglyceride?

There are two sorts of fatty substances in the blood: cholesterol and triglycerides. These are often referred to together as lipids.

Cholesterol

Although some of our cholesterol comes from the foods we eat, the majority is produced naturally in the liver. We need cholesterol to stay healthy because every cell in our body uses it to make cell membranes. We also use cholesterol to make hormones and help digest food. There are two types of cholesterol; LDL and HDL.

Low-density lipoprotein (LDL)	High-density lipoprotein (HDL)
LDL carries cholesterol to the cells. If there is too much, it can build up in the arteries (the tubes that carry blood away from the heart to the rest of the body), clogging them up and causing high blood pressure, heart attacks, and strokes. For this reason, LDL cholesterol is known as ‘bad cholesterol’ and lower levels are better.	HDL carries cholesterol away from the cells, including back to the liver where it can be passed out of the body as a waste product. For this reason, it is sometimes referred to as ‘good cholesterol’

Non-HDL

This is simply your total cholesterol minus your HDL. It includes both LDL cholesterol and a small amount of cholesterol that is carried with the triglycerides. Both sorts of cholesterol can cause narrowing of blood vessels, so lower levels are better.

Cholesterol:HDL Ratio

Your healthcare team may also talk to you about your total cholesterol:HDL ratio. This is used to help calculate your risk of CVD and lower levels are better.

Triglycerides

Triglycerides are an important source of energy. They come from the foods you eat, especially meat, dairy products, and cooking oils, as well as being made in the liver. Slightly high triglycerides may cause narrowing of the blood vessels. Extremely high triglycerides can also cause a condition called pancreatitis which is potentially very dangerous.

How are lipids measured?

Cholesterol and triglycerides are measured using a blood test.

The blood can either be taken by pricking your fingertip or, more commonly, from your arm with a needle. If the finger prick test shows a high cholesterol, you are likely to be asked for another sample taken from your arm.

You might be asked to do a “fasting” blood test. This means not eating or drinking anything apart from water for up to 12 hours before the test.

Who should have their blood fats (“lipids”) measured?

Your GP will have a system in place for working out who is at risk of CVD and who needs a test.

Generally, most people over the age of 40 will be called for a test at some point. In addition, if cholesterol or heart problems run in your family, if you are overweight or if you have diabetes or another medical problem that increases your risk of CVD (i.e. diseases affecting the blood vessels like heart attacks and strokes), your GP will want to measure your lipids.

What should your cholesterol and triglycerides be?

The table below is a rough guide for healthy lipid levels for adults in the UK.

Cholesterol is just one of a number of risk factors for CVD; if you have a medical condition such as diabetes or heart disease, your target may be lower. Your healthcare team will tell you what levels are right for you.

Lipid Type	Healthy Level (mmol/L)
Total cholesterol	Below 5.0
LDL cholesterol	Below 3.0
HDL cholesterol	Men - above 1.0 Women - above 1.2
Non-HDL	Below 4.0
Non-fasting triglycerides	Below 2.3
Fasting triglycerides	Below 1.7

 

What causes high cholesterol and triglycerides?

There are lots of things that can contribute to high cholesterol and triglycerides; for most people, it is a combination of causes:

	Diet – eating an unhealthy diet, especially too much saturated fat, will put up both your cholesterol and triglycerides.
	Weight – carrying too much weight, especially around your middle, increases both cholesterol and triglyceride.
	Physical activity – being inactive increases your LDL and triglycerides, whilst lowering your HDL.
	Alcohol – alcohol is broken down in the liver where it can be converted into cholesterol and triglyceride, so drinking more than is recommended will increase all your lipids.
	Smoking – smoking reduces your HDL, clogs up your blood vessels and makes your LDL more likely to stick to the sides of your blood vessels, narrowing them even further.
	Medication – some medications can increase the levels of triglyceride and cholesterol.
	Medical conditions – there are a number of medical conditions that can increase lipid levels, including underactive thyroid, kidney problems, liver problems, and diabetes.
	Age – cholesterol and triglyceride levels tend to rise as you get older.
	Genes – high cholesterol runs in some families and alterations in specific genes can cause very high cholesterol levels.
	Menopause – cholesterol levels can rise after the menopause.