Cholesterol

Friend or foe?

By Xavier Fox

Understanding cholesterol is very important for maintaining a healthy body, especially a sound cardiovascular system. Though often mentioned in passing in articles on nutrition it’s time you became more intimately acquainted with its good and bad aspects.

Cholesterol exists in our bodies as a “fatty” like substance and is used in many cell functions. Throughout the day, your body manufactures enough cholesterol to satisfy its needs, indeed 70% of the cholesterol in your system is made in your liver.
Cholesterol also plays an important role in hormone production. It is the precursor for steroid hormones, bile acids and pro-vitamin D. Bile acids are used by the body to digest fats. In addition to being the building block for steroid hormones, cholesterol is also a component of the cell membrane. It is the component responsible for permitting steroid hormones to enter a cell, bind to the hormone receptor and stimulate the required genes. So, your body does need cholesterol. Not all cholesterol is bad. It is also very important to those who want to add muscle. The key is to keep your total cholesterol levels under control.
Studies have shown that diets high in saturated fats are the culprits for increased amounts of cholesterol in the blood. This is why it is recommended that only 10% of total daily calories should come from saturated fats. Keeping your diet low in fat, especially saturated fat, decreases plaque build-up on the artery walls.
How many times have you heard people refer to their cholesterol levels when talking about their latest visit to the doctor? Do you have any idea what this level means? First of all, a high cholesterol level is a convincing statistic when it comes to predicting that a person will be susceptible to coronary heart disease. Therefore, if you have an elevated total cholesterol level, you are at risk for coronary heart disease. This is mostly caused by the cholesterol causing a build-up of plaque in the arteries, which causes high blood pressure. As the plaque builds up, the walls of the artery become thicker and make the pathway through the artery smaller. (Imagine if you narrowed the inside of a straw. It would take more pressure than before to get the same amount of liquid through the straw in the same amount of time due to less free space being available inside of the straw.)
Plaque can build to a point where the vessels completely close and block blood flow, causing a heart attack. The last time I checked, heart attacks were not synonymous with good health and will not help you get bigger and stronger. So, what are the levels that are predictors for these situations? As levels rise above 180 mg/dl, the risk for developing coronary heart disease increases. A cholesterol value of 220 mg/dl correlates to almost twice the number of people with coronary heart disease as compared to the 180 mg/dl level. As a matter-of-fact, by simply reducing your cholesterol value by a mere 1%, you can reduce your risk for coronary artery disease by 2% for levels over 200 mg/dl.
Levels should not reach above the 220 mg/dl level. Levels higher than that would put you into the top 10% of people at risk for coronary heart disease. If your levels range between 200 and 240 mg/dl then you should change your diet to one much lower in fat. In addition, if you have other heart disease risk factors such as cigarette smoking, obesity or high blood pressure, you should have a doctor do a complete lipid profile. If you are tested and are above the 240 mg/dl level, then you should immediately receive more comprehensive testing and get treatment.
Now, before you get your self all stirred up and feel like you need to run to your physician’s office and get tested right away, there is more to the story. There are two main types of cholesterol that make up your total cholesterol level, so the total cholesterol level may not tell the complete story (although it is a very good indicator). Do you remember the part that said cholesterol can build up in your arteries and be deposited as plaque? (You better remember, you only read it two minutes ago!) Well, that is due to the form of cholesterol known as low density lipoprotein (LDL), or better known as bad cholesterol. The other type, good cholesterol, is high density lipoprotein (HDL). (I bet you saw that name coming.) You see, cholesterol is not water-soluble. Therefore, it needs help getting through the blood stream. HDL helps little packets of cholesterol to form and be transported through the blood stream to the liver where it can be processed. This sounds kind of contradictory, but low density lipoprotein contains more cholesterol than high density lipoprotein and does not aid in transporting cholesterol through the system. LDL is why you get plaque build up in your arterial walls. Another thing that sounds counter-intuitive is that the smaller LDL particles have shown to increase the risk of coronary heart disease over the larger LDL particles.
Although the total cholesterol level (TC = HDL + LDL) is a reliable way to predict cardiovascular disease, the real indicator should be the ratio of HDL to total cholesterol (HDL/TC). If two people each have a TC of 200mg/dl but one has a HDL ratio of 75% while the other has 30%, the one with the higher HDL level will be at a lot less risk of coronary heart disease even though they both have the same TC level. HDL levels are inversely related to the risk of coronary heart disease. The higher the HDL level, the lower the risk. HDL levels are also four times better at predicting coronary heart disease than LDL levels and eight times more effective than the total cholesterol reading alone. The ratio of TC to HDL that is recommended is between 4.0 and 4.5 (that means that at most, your total cholesterol level should only be about 4 times greater than your HDL level, or your HDL makes up at minimum a quarter of your total cholesterol level). The higher that ratio becomes, the more at risk you are. The following table lists some measurements of risk related to TC/HDL ratios:
When cholesterol circulating in the blood stream reaches elevated levels, the cells’ ability to make their own cholesterol becomes inhibited due to the system shutting down the liver enzyme that is responsible for producing cholesterol. Thus, the entire cholesterol synthesis process gets interrupted. Incoming LDL-derived cholesterol promotes the storage of cholesterol in the cell by activating an enzyme which reattaches a fatty acid to excess cholesterol molecules. This results in cholesterol esters that are deposited in storage droplets. When the body senses that cholesterol is accumulating in the cell, it sends a signal to stop the production of new LDL receptors. Since our bodies are highly adaptive, the cell will actually change the amount of its receptors so only enough cholesterol is transported to satisfy the body’s needs.
Chylomicrons are large lipoprotein molecules that transport ingested cholesterol from the intestinal tract into our body and to the liver. Once they have gone into the liver, chylomicrons are broken down and the liver then secretes cholesterol in the form of very low density lipoprotein (VLDL). Cholesterol is one of VLDL’s fundamental ingredients. The VLDL molecules are then discharged into the blood stream to be transported to the tissues requiring them. VLDL is then converted into low density lipoprotein (LDL) once it penetrates into fat tissues storage areas. LDL is the major transport form for cholesterol. In the LDL form, cholesterol is transported from the fat tissues to many different bodily tissues. high density lipoprotein (HDL) is involved in the transport of cholesterol from the tissues to the liver, which is the opposite direction of flow to LDL.
In addition to keeping body fat and fat ingestion low, it is helpful to eat adequate amounts of dietary fibre. Fibre binds to bile acids, which are made up of cholesterol, and then removes the cholesterol from the body by waste. The fibre actually changes the chemical composition of the bile acids created from LDL cholesterol and slows cholesterol synthesis. Aerobic exercise also helps you to keep your LDL levels in the safe range.
As you can see, cholesterol plays a very important role in a bodybuilder’s development. It plays a key role in the development of steroid hormones, which in turn helps you to develop muscle. Cholesterol also acts as a “guardian” component of the cell membranes by deciding what is permitted to enter or leave a cell. It even aids in the digestion of fat. Keeping your diet low in saturated fat is a great way to maintain healthy cholesterol levels so you won’t have to worry about high blood pressure or coronary disease. Your liver will produce all the cholesterol your body needs, so limiting the amount of saturated fats you consume will not affect the production of this vital lipid.