Cholesterol – The Good, the Bad and the Ugly

Hypercholesterolemia is the presence of abnormally high levels of cholesterol in the blood. Cholesterol is an essential molecule from which hormones and steroids are made. It is also used in maintaining nerve cells. Approximately 75 percent of the cholesterol that circulates in a person’s bloodstream is made by the person’s liver. The remainder is acquired from outside sources. Cholesterol is found in animal sources of food and not found in plant sources.
A normal cholesterol level is less than 200 milligrams per decilitre (mg/dL) of blood. A range between 200 to 239 mg/dL is considered borderline for blood cholesterol. Hypercholesterolemia is a condition whereby the cholesterol levels exceed 240 mg/dL. Cholesterol can be divided into 2 major categories: low-density lipoprotein (LDL), also known as the "bad" cholesterol and high density lipoprotein (HDL), the "good" cholesterol.

 

 

Triglycerides, HDL and LDL cholesterol

LDL molecules are the major carriers of cholesterol and each one contains approximately 1500 cholesterol esters. Cholesterol is used by the cells for the synthesis of cell membranes. Cholesterol is taken into the cells through receptors present on the cell membrane. When the amount of cholesterol in the cells is in abundance, the synthesis of the receptors is down-regulated to prevent further uptake of cholesterol into the cells. When this happens, there will be excessive amounts of LDL molecules in the blood. These LDL molecules are oxidised and taken up by the macrophages, which becomes engorged and turns into foam cells. Foam cells become trapped in the walls of the blood vessels and contribute to the formation of atherosclerotic plaque. These plaques are the main causes of heart attacks, strokes and other serious medical conditions, leading the association of the LDL cholesterol with “bad” cholesterol. HDL cholesterol is responsible for the transport of cholesterol to the liver for excretion or to other tissues that use cholesterol for hormone synthesis through a process known as reverse cholesterol transport. High amount of HDL cholesterol present correlates to better health outcomes as it removes excessive cholesterol, thus lowering the risks of the formation of atherosclerotic plaques. Therefore it is known as the “good” cholesterol.
Triglycerides are a type of fat that is found in the blood. It is an ester derived from glycerol and three fatty acids. They are the components of very low density lipoproteins (VLDL) and chylomicrons, playing an important role in metabolism as energy sources and transporters of dietary fats. They contain more than twice as much energy as carbohydrates and proteins. High levels of triglycerides in the bloodstream have been associated with increase risks of atherosclerosis, heart diseases and strokes.
Diet, exercise, smoking, alcohol and certain illnesses can affect the levels of both types of cholesterol. Eating a high fat diet will cause LDL cholesterol to increase while exercising and reducing body weight will increase HDL cholesterol and lower LDL cholesterol.

Causes of hypercholesterolemia

The most common cause of hypercholesterolemia is eating foods that are rich in saturated fats or contains high levels of cholesterol. It may also be caused by underlying diseases that elevates blood cholesterol levels such as diabetes mellitus, kidney disease, liver disease or hypothyroidism. It can also be caused by an inherited disorder in which cholesterol is not properly metabolised by the body. Obesity, generally resulting from eating a high fat diet, also may lead to raised levels of blood cholesterol. This is because obesity itself causes the body to produce excessive amounts of cholesterol.

Dangers of having high blood cholesterol levels

Hypercholesterolemia increases the risks of heart disease. High levels of circulating cholesterol cause deposits to form inside the blood vessels. These deposits, called plaques, consist of fat deposits from the bloodstream. When the plaques become large enough, they block the blood vessels and decrease blood flow. This result in a disease process called atherosclerosis, which causes blood clots to form that ultimately will stop blood flow. If it happens in the brain, it results in a stroke in a portion of the brain. If it occurs in the arteries supplying the heart, a heart attack occurs. Below is an image of an athersclerotic plaque on an artery supplying blood to the heart.

Symptoms of high cholesterol

Hypercholesterolemia is asymptomatic. There are no symptoms visible to the naked eye. It is diagnosed in a blood test or after a heart attack or stroke occurs.

Treatment of hypercholesterolemia

Initial treatment usually requires dietary changes to reduce the consumption of total fats, saturated fat and cholesterol. It is recommended to increase the intake of food containing soluble fibers such as bran, whole grains and indigestible fibers such as lignin. Omega 3 fatty acids and fish oils have shown to increase the levels of HDL and lower triglycerides. It would be ideal if the person can reduce weight so that it is close to the ideal Body Mass Index (BMI). In addition to diet, a lifestyle change is necessary. The person need to incorporate regular exercise and if the person is a smoker, to stop smoking.

The purpose of treating elevated cholesterol levels is to reduce the risks of complications. For every 1 percent reduction in cholesterol level, the risk of heart disease is reduced by 2 percent. If the dietary and lifestyle change does not reduce the person’s cholesterol levels, medications may be required.

Alternative treatments

There are advocates of treatments using vitamins, minerals and antioxidants in relatively high dosages. Advocates of such therapies also emphasize increased levels of exercises, achieving a BMI that is ideal or close to ideal and increasing the intake of dietary fiber. There are treatments that use garlic, soy and isoflavinoids to lower serum cholesterol levels. In 2003, green tea was found to be an effective addition to low-fat diet for lowering cholesterol. Other than green tea, red yeast rice also helps to maintain healthy cholesterol levels.

Prevention

There are several steps that are suggested to maintain serum cholesterol within normal limits. They include:
• Maintaining an ideal weight appropriate for the height or reducing weight if it is inappropriate
• Changes in dietary habits such as reducing the intake of fat and cholesterol rich foods, and increasing the intake of dietary fiber
• Avoid or stop smoking
• Regular aerobic exercise
Food is readily available nowadays and people are often spoilt for choice. Most of the time, people make wrong food choices. Food is now so palatable that people tend to overeat. There are easy steps on how people can make the correct choices and eat the correct servings. There are also easy ways for people to stay healthy by incorporating exercise into their lifestyle without drastic changes to their lives.