The good, the bad: Cholesterol

Nearly 2,300 people die every day due to cardiovascular disease and it is the leading cause of death in the United States, according to the American Heart Association (AHA).

High cholesterol can lead to cardiovascular disease. Reducing the risks can be achieved by managing the body's cholesterol levels through diet, exercise, lifestyle and medications.

There are two types of cholesterol, the 'good' and the 'bad.' Too much of one or not enough of the other can put you at risk for coronary heart disease, heart attacks and strokes.

The AHA recommends, "Everyone should start getting a cholesterol test at age 20, but it's a good idea to start having cholesterol checked at an early age. Even children, especially those in families with a history of heart disease, can have high cholesterol levels."

Evidence exists that children with a family history of heart disease are at greater risk for developing heart disease as adults, advises the AHA. "Lack of regular physical activity, poor dietary habits and genetics can all affect a child's cholesterol levels."

Where is cholesterol found?

According to the AHA, HDL is the 'good' cholesterol which helps keep the LDL 'bad' cholesterol from getting lodged into your artery walls, a cholesterol screening measures the HDL and LDL lipid levels.

Food and the body are the two sources cholesterol comes from. 75 percent of blood cholesterol comes from the body's liver and other cells, the other 25 percent is from the foods we eat, specifically, in animal products.

Michael S. Fenster, M.D., certified interventional cardiologist at Hernando Heart Clinic/Cardiology Specialists of Florida in Brooksville said, "It is a common misconception that people need to consume cholesterol, although it is essential for proper bodily functioning."

Typically, the body makes all the cholesterol it needs, so people do not need to consume it. It is more important to watch the intake of saturated fatty acids, as they are the main culprit in raising blood cholesterol, Fenster added.

"Eating saturated fats, and to a lesser degree dietary cholesterol, can increase your cholesterol level. If high blood cholesterol runs in your family, lifestyle modifications may not be enough to help lower your LDL blood cholesterol, so work with your doctor to find a treatment plan that's best for you," recommends the AHA.

Limiting food high in saturated fat and especially trans fatty acids, may help lower your LDL (bad) cholesterol, because the saturated fatty acids are what the liver uses to manufacture cholesterol, suggests Fenster.

"There are wide genetic variations in both the amount of cholesterol produced as well as the types of lipoproteins produced. The body compensates for cholesterol intake by reducing the amount synthesized," said Fenster.

Everyone is different when it comes to LDL cholesterol being produced naturally by the body. Some inherited genes can cause the body to make too much, adds Fenster.

Intestinal excretion is the only way to get rid of cholesterol in the body. Cholesterol cannot be metabolized. The intestines absorb the cholesterol from food and can also re-absorb about 50 percent of the excreted cholesterol from bile, which is produced by the liver, he added.

Healthy levels of HDL may help protect against heart attack and stroke, while low levels of HDL, less than 40 mg/dL for men and less than 50 mg/dL for women, have been shown to increase the risk of heart disease, advises the AHA.

Triglycerides
Triglycerides are a chemical form in which most fat exist in food as well as in the body. They are also present in plasma, and in association with cholesterol, form the plasma lipids.

Triglycerides in plasma are from fats in eaten foods or made in the body from other energy sources like carbohydrates. Calorie intake from a meal that is not used immediately are converted into triglycerides and transported to fat cells to be stored.

Lack of physical inactivity, cigarette smoking, excess alcohol consumption and a diet very high in carbohydrates, up to 60 percent of total calories or more can cause triglyceride levels to increase, according to the AHA.

Elevated triglyceride levels can be linked to causing coronary artery disease, diabetes and overweight/obesity.

People with high triglycerides often have a high total cholesterol level, including a high LDL (bad) level and a low HDL (good) level. Many people with heart disease and/or diabetes also have high triglyceride levels, according to the AHA.

What causes blockages
Cholesterol itself does not cause blockages in the body. As mentioned, cholesterol is a component of many different lipoprotein molecules, which can vary in both size and number, and that can get into the artery walls.

It's important to note that cholesterol can not dissolve in the blood. It has to be transported to and from cells by these structures called lipoproteins, said Fenster.

"Our bodies manufacture lipoproteins, which can vary with genetic pre-dispositions. These structures contain a lipid, or fat core surrounded by a layer with different proteins and other components that allows them to be transported through the blood stream and into cells, and cholesterol is a component of these structures," he said.

Once these structures enter the lining of the blood vessel, the cholesterol contained within them can be 'oxidized,' which is a type of chemical transformation, Fenster describes. The oxidized molecules cause inflammatory changes, and over time this can lead to plaque being built up, causing narrowing of the arteries. These plaques may also rupture causing a clot to form and blocking the blood flow in the artery.

Lp(a) is the fourth lipid found in the blood, and is a genetic variation of LDL lipids. It is a risk factor for the premature development of fatty deposits in arteries, from the AHA. "Lp(a) isn't fully understood, but it may interact with substances found in artery walls and contribute to the buildup of fatty deposits."

Most of the time high cholesterol has no symptoms. It is important to have cholesterol levels checked by a doctor to help reduce your risk of heart disease and stroke. Even if you have 'good' levels now, it is never too early to develop healthy habits to keep your risk low.