What is high cholesterol?
Cholesterol is a fatty substance known as a lipid. The majority of the cholesterol in our bodies is manufactured by the liver. Cholesterol is, in fact, vital to the normal functioning of the body and, contrary to what many may suppose, we need a certain amount of cholesterol to keep healthy.
Cholesterol is used by the body to make up the outer layer of every cell in the body and to insulate nerve fibres. It is also used to make hormones and the bile acids which we need to digest and absorb fats.
Cholesterol is carried round the blood by molecules known as lipoproteins. The two main lipoproteins are LDL (low density lipoprotein) cholesterol and HDL (high-density lipoprotein) cholesterol. LDL cholesterol makes up the majority of cholesterol in the blood and is often known as ‘bad’ cholesterol because it can cause a build-up of harmful deposits when there is too much cholesterol in your blood for the cells to use. So, ideally, we want lower levels of LDL.
HDL cholesterol is often called ‘good’ cholesterol as it aids the body in disposing of the cholesterol in our blood stream by carrying it back to the liver which either breaks it down or cause it to be passed from the body as waste. So, ideally, we want higher levels of HDL.
Another type of cholesterol is VLDL (very low density lipoprotein) which helps to distribute triglycerides (a type of fat found in the blood) through the blood stream. A certain amount of VLDL also converts to LDL. Unlike LDL and HDL, VLDL cholesterol levels are not measured directly but estimated based on the measurement of triglyceride levels in the blood.
This is the reason why a blood test that measures cholesterol levels, also includes a measurement for triglycerides. High cholesterol, then, is a higher than normal level of HDL, or ‘bad’ cholesterol, often combined with a lower than normal level of LDL, or ‘good’, cholesterol and a high level of triglycerides.
Why you might want to lower your cholesterol
High cholesterol itself is not a disease but it significantly increases your risk of serious medical conditions such as heart disease and stroke. With high cholesterol small fatty lumps accumulate on the walls of the arteries which can lead to a condition known as atherosclerosis or ‘hardening of the arteries’ which makes the arteries narrower and therefore restricts the flow of blood to your heart, brain, or other parts of the body.
In turn, this increases the chances of a blood clot forming which, on top of a previous narrowing, can block the artery completely, stopping the blood from flowing. If the blocked artery leads to a portion of the heart or brain, this can cause a heart attack or stroke. Other heart or vascular diseases caused by atherosclerosis include angina, TIA (transient ischaemic attack) and peripheral vascular disease.
How to lower your cholesterol
Several factors can lead to high cholesterol, some of which, such as heredity and genetics, are beyond our control. However, lifestyle and diet are key factors in increasing the risk of developing high levels of blood cholesterol.
An unhealthy diet, made up of large amounts of food types containing saturated fats is a major, but easily preventable, cause of high cholesterol. For many people with high cholesterol, a diet low in saturated fats can substantially reduce levels of LDL (bad) cholesterol.
A healthy, balanced diet can lead not only to lower levels of LDL in the blood but can also increase HDL (good) cholesterol levels, helping to keep the ‘bad’ cholesterol at bay. In addition a low fat diet, combined with some regular, moderate exercise can also lead to weight loss, which in turn can help normalize cholesterol levels.