Why lower high cholesterol?

Heart disease is one of the major causes of death for both men and women in the Western world. There are a number of factors that are associated with an increased risk of heart disease such as smoking, high blood pressure, obesity and diabetes. High cholesterol levels are also commonly believed to be associated with increased risk and there has therefore been a huge amount of focus on lowering cholesterol levels, especially in those individuals who have multiple risk factors.

What is Cholesterol?

Cholesterol is actually vital to the body in numerous ways. It is an essential part of cell walls; it is needed in high concentrations in the brain, where it plays a major structural role; it forms part of the protective myelin sheath covering the nerves and is needed for nerve transmission; it protects skin against water soluble toxins and holds water to prevent desiccation; without cholesterol our bones would be hollow. Cholesterol is also used by the body to repair damage; it is a major component of scar tissue.

In addition to all this, cholesterol is the precursor to many other substances required by the body. It plays a role in the production of bile (which, among other things, is essential in processing the fat in our diets); in the production of steroid hormones, such as testosterone, progesterone and oestrogen; in the creation of vitamin D and the metabolism of fat soluble vitamins (such as vitamins A, D, E, and K).

Cholesterol is known to directly affect the activity of serotonin (which affects mood, sense of wellbeing, etc), with low cholesterol levels being associated with depression. It should also be noted that cholesterol is an antioxidant, which protects us against cancer, aging, and disease.

In short, cholesterol is absolutely vital to the functioning of the body and the body therefore needs an adequate supply of it.

Where does cholesterol come from?

Most of the cholesterol in our body is not obtained directly from cholesterol in foods (although it is probably best to limit your intake of high cholesterol foods, such as eggs and cheese) but is manufactured by the body, in particular in the liver but also in areas such as the intestines, adrenal glands, and reproductive organs.

Cholesterol is manufactured from the carbohydrates and fats in the foods that we eat. It is believed that processed carbohydrates (especially refined sugars) and excessive non-essential fatty acids are particularly likely to result in high LDL cholesterol levels. However the body does have the ability to regulate the amount of cholesterol it produces, depending on its needs and the availability of dietary cholesterol.

Types of Cholesterol

If you read about cholesterol, or talk to your doctor about it, you will probably find out that there are different types of cholesterol, which are commonly referred to as “good” and “bad” cholesterol.

“Good” & “Bad” Cholesterol

“Good” cholesterol is also known as HDL cholesterol (High Density Lipoproteins), while “bad” cholesterol is also known as LDL cholesterol (Low Density Lipoproteins). You may also hear about triglycerides, another type of fat molecule found in the blood.

Lipoproteins are classified according to the proportion of fat to protein that they carry. Very low density lipoproteins (referred to as VLDL) contain the highest proportion of fat to protein (the greater the amount of fat, the lower the density of the lipoprotein). High density lipoproteins contain more protein than fat.  As the body releases the content of the particles into the cells of every organ, some VLDLs are converted into LDLs, which contain the most cholesterol. It is generally the levels of LDL and HDL that are referred to when cholesterol is talked about.

Triglycerides are a non-cholesterol fat which forms most of the dietary fat that we consume and most of the fat in the bloodstream. Although triglycerides are also essential for health (the tissues of the body depend on them for energy) many scientist believe that high levels of triglycerides may also be a risk factor for heart disease.

Although HDL and LDL are both forms of cholesterol, they play quite different roles within the body. The LDL carries cholesterol from where it is manufactured (mainly in the liver) and circulates it around the body to the cells that require it. The HDL carries cholesterol that is not being used from the arteries back to the liver where it can be excreted. This process is sometimes referred to as reverse cholesterol transport.

In another article I will explain why it is believed that high levels of LDL cholesterol contribute to the risk of heart disease, the evidence that exists to support these views and alternative theories and evidence that suggest that the presence of cholesterol is a result of certain problems and not the cause of them. I will also be looking at the implications of trying to reduce LDL cholesterol levels (and/or increase HDL cholesterol levels) with drugs such as Statins.