Cholesterol – What It Is And Why We Need It.

Over the past number of years the word ‘cholesterol’ has become a common term. However, what is it really and why all the talk about it?

What Is Cholesterol

Cholesterol is a soft, waxy substance found among the fats (lipids) in the blood. Produced in the liver, this slippery substance is not a fat, but actually a steroid and plays a central role in many biochemical processes. Daily the liver produces about 1,000 milligrams of cholesterol.

What Does It Do?

It is an important structural component of cell membranes. As such it helps to strengthen cell walls and is vital in the exchange of nutrients and waste materials across membranes. It is present in higher concentrations in tissues which either produce more or have more densely packed membranes such as the liver, brain and spinal cord. Related to the brain and spinal cord, it is so important in the functioning of nerve impulses that without it you would not be able to move a muscle.

It plays a major role in the production of steroid hormones which are responsible for normal functioning and development. These include the female sex hormones estrogen and progesterone and the male hormone testosterone, which contribute to the development of the physical characteristics of adult females and males, as well as playing a role in reproduction.

The adrenal hormone aldosterone is also produced with cholesterol being a precursor. This hormone increases the re-absorption of sodium and water and the release of potassium in the kidneys. Simultaneously it regulates sodium and potassium levels, helping to maintain both blood pressure and bodily fluids.

Cortisol is another steroid hormone produced from cholesterol. It is involved in regulating blood-sugar levels as well as defending the body against infection and is involved in inflammatory response.

When the body is exposed to sunlight, cholesterol residing under the skin is involved in the production of vitamin D which is responsible for strong bones and teeth.

Cholesterol is used in the production of bile which is a greenish fluid produced in the liver, stored in the gallbladder and is needed to digest dietary fat.

Because cholesterol is water-insoluble, and blood is mostly water, the body wraps the cholesterol in specialized protein carriers to be transported through the bloodstream. This union of the cholesterol and the protein is called a lipoprotein.

Two types of proteins transport the cholesterol, differing in size and amount required to carry the cholesterol. The protein combining with the cholesterol to form the low density proteins (LDLs) are larger in size so require fewer to carry the cholesterol, making them less dense. These carry cholesterol to the cells.

The proteins in the high density lipoproteins (HDLs) are smaller in size requiring more to transport the cholesterol thus making them denser. They take excess cholesterol from the cells back to the liver for processing or elimination.

If Cholesterol is So Vital, Why All The Negative Talk?

High levels of LDLs (often called ‘bad cholesterol’) in the bloodstream have been linked to heart disease. When the muscle in the arterial wall is damaged through oxidation, LDLs start to build up as part of the repair process. This can lead to a condition known as arteriosclerosis. The build up can reach such a level that the arteries that supply blood to the heart itself, or other major organs such as the brain, become so restricted that the organs receive an inadequate supply of blood to function properly, which can then lead to a heart attack or stroke.

In contrast, high density lipoproteins, coined ‘good cholesterol’ do not build up in the arteries. In fact research indicates that HDLs are able to removed accumulated plaque in the arteries and may even reverse arteriosclerosis.

More and more, research is suggesting that cholesterol ingested from the food we consume does not play a role in cholesterol levels.

Since a high cholesterol level does not present with symptoms, the only way to determine the level is by having a blood test.