Understanding Cholesterol

What is cholesterol?

Cholesterol is a waxy, fat like substance found in the body's cells and in the blood stream. It is important for the body to function properly. Unfortunately, when cholesterol levels become too high, it can lead to an increased risk of heart disease and stroke.

Where does cholesterol come from?

Approximately eighty percent of cholesterol is made in the liver. The remaining twenty percent is absorbed from the food we eat, such as meat, poultry, fish, dairy products and sweets.

Are there different kinds of cholesterol?

Yes, when you have your cholesterol levels checked, three readings are important.

• LDL - Low Density Lipoprotein - commonly referred to as 'bad' cholesterol because it can build up in the arteries increasing the risk of a heart attack or stroke
• HDL - High Density Lipoprotein - referred to as 'good' cholesterol because it helps to lower cholesterol levels
• Triglycerides - High levels of triglycerides can also lead to heart attack and stroke.

How does cholesterol help the body to function properly?

LDL is used by the body to:

• become part of cell membranes
• form a protective covering over nerves
• form Vitamin D
• produce a number of the body's hormones
• produce some of the enzymes that help us break down our food
• to form bile acids, which help us absorb fat into the body

HDL carries the extra cholesterol that the body does not need back to the liver to be broken down and removed from the body. It is also believed that HDL possibly removes some cholesterol from plaques, slowing their growth.

If cholesterol is necessary for a healthy functioning body, why is it important to have low cholesterol levels? When there is too much LDL in the body and not enough HDL to get rid of the excess, LDL cholesterol begins to build up in artery walls in the form of hard plaques. Arteries are important for carrying oxygen and nutrients throughout the body. The plaques cause arteries to become narrow and hardened, decreasing the blood flow to important organs. Arteries may even become blocked, causing a heart attack, stroke, kidney damage or blindness, depending on which artery is blocked. Arteries can become blocked by:

• the plaque growing until it fills the artery
• a piece of plaque breaking away and traveling to a smaller artery, blocking it
• a blood clot forming around a plaque

Some people report having levels of cholesterol that are 5 while others report cholesterol levels of 200 or more. Do cholesterol levels really vary by that much?

No, some labs report cholesterol levels and triglyceride levels in mg/dl, while other labs report levels as mmol/L. The mg/dl measurements are the larger numbers and mmol/L smaller ones. You can convert measurements from one to the other easily.

To convert cholesterol levels from mg/dl to mmol/L you need to divide by 39.
To convert cholesterol levels from mmol/L to mg/dl you need to multiply by 39.

To convert triglyceride levels from mg/dl to mmol/L you need to divide by 89.
To convert triglyceride levels from mmol/L to mg/dl you need to multiply by 89.