As you get older it is thought your arteries naturally begin to harden and narrow, leading to atherosclerosis.
However, there are a number of things that accelerate this process. These are described below
High-fat diets and cholesterol
Cholesterol is a type of fat that is essential for the functioning of the body. Cholesterol helps to produce hormones, make up cell membranes (the walls that protect individual cells) and protect nerve endings.
There are two main types of cholesterol:
- Low-density lipoprotein (LDL) is mostly made up of fat, plus a small amount of protein. This type of cholesterol can block your arteries, so it is often referred to as 'bad cholesterol'.
- High-density lipoprotein (HDL) is mostly made up of protein, plus a small amount of fat. This type of cholesterol can help to reduce any blockage in your arteries, so it is often referred to as 'good cholesterol'.
Most of the cholesterol your body needs is manufactured by your liver. However, if you eat foods high in saturated fat, the fat is broken down into LDL ('bad cholesterol').
Foods high in saturated fat include:
- processed meat
The LDL cholesterol sticks to your artery walls in the form of fatty deposits which, over time, gradually build up and reduce, or completely block, your blood supply. The fatty deposits are also known as plaques or atheroma.
As well as a high-fat diet, a lack of regular exercise, being obese and drinking excessive amounts of alcohol can also increase the levels of LDL cholesterol in your body. The medical term for having high cholesterol is hyperlipidemia.
Smoking can damage the walls of your arteries. If your arteries are damaged by smoking then blood cells, known as platelets, will clump together at the site of the damage to try to repair it. This can cause your arteries to narrow.
Smoking also decreases the blood's ability to carry oxygen around your body, which increases the chances of a blood clot occurring.
Read more about the health risks associated with smoking.
High blood pressure
If you have high blood pressure (hypertension) it will damage your arteries in the same way as cigarette smoke. Your arteries are designed to pump blood at a certain pressure. If that pressure is exceeded, the walls of the arteries will be damaged. High blood pressure can be caused by:
- being overweight
- drinking excessive amounts of alcohol
- a lack of exercise
Read more about high blood pressure.
If you have poorly controlled type 1 or type 2 diabetes, the excess glucose in your blood can damage the walls of your arteries.
Read more about Type 1 diabetes and Type 2 diabetes.
Being overweight or obese does not directly increase your risk of developing atherosclerosis and cardiovascular disease (CVD), but it does lead to related risk factors that do. In particular, overweight or obese people:
- have an increased risk of developing high blood pressure
- tend to have higher levels of cholesterol as a result of eating a high-fat diet
- have an increased risk of developing type 2 diabetes
Read more about obesity.
Drinking an excessive amount of alcohol can cause high blood pressure (hypertension) and raised blood cholesterol levels, increasing your risk of developing atherosclerosis and CVD.
Read more about alcohol misuse.
If you have a first-degree relative (a parent, or a brother or sister) with atherosclerosis and CVD, you are twice as likely to develop similar problems compared with the population at large.
Rates of high blood pressure and diabetes are higher among people of African and African-Caribbean descent. This means that people in this group also have an increased risk of developing atherosclerosis and CVD.
People of South Asian descent (those from India, Bangladesh, Pakistan and Sri Lanka) are five times more likely to develop diabetes than the population at large. Again, this increases the risk of this group developing atherosclerosis and CVD.
Read more about health issues that affect black people and health issues that affect people of South Asian descent.
Recent research suggested that air pollution, in particular traffic pollution, can cause a slight increase in levels of atherosclerosis.
Researchers found that people living within 50 metres of a major road had higher levels of atherosclerosis than would otherwise be expected.