Lipids in the Bloodstream

The amount of lipids, or fats, in the bloodstream directly influences the health of a person's cardiovascular system. Two main types of lipids circulate through the bloodstream: cholesterol and triglycerides.



High levels of overall cholesterol or triglycerides can lead to heart attacks. The National Cholesterol Education Council (NCEC) recommends that people 20 years of age or older have a complete fasting blood lipid profile every five years.

Cholesterol

• Cholesterol, a waxy fat that the human body uses to produce bile, also builds cell walls and assists in the manufacture of hormones. The liver manufactures 80 percent of the body's cholesterol. A diet heavy in animal products such as meat, eggs and dairy, results in the ingestion of additional cholesterol.

  A healthy total cholesterol level remains below 200. A level over 240 is considered high, and puts the patient at risk for artery plaque formation. Decreasing consumption of high-cholesterol foods and increasing exercise can reduce a person's levels of harmful blood lipids and contribute to a healthier heart and longer lifespan. Sometimes, a doctor must prescribe cholesterol-lowering medications to achieve this result.

Triglycerides

• Triglycerides, another type of lipid, flow through the blood plasma. They are the chemical form of most fats found in food and what fat deposits within the body are made of. Triglycerides account for 95 percent of the body's fatty tissue.

  Triglycerides enter the body through the consumption of fatty foods, and form within the body after eating too much of other types of foods, especially carbohydrates. When a person ingests too many calories during a meal, the body converts the excess energy into triglycerides and transports it to fat cells for storage. Later, hormones regulate the release of triglycerides from these fat stores to meet the body's requirement for energy between meals.

  Normal triglyceride levels range from 40 to 160 mg/dL for men and 35 to 135 mg/dL for women. Levels greater than 199mg/dL are considered high. Excess triglycerides contribute to cardiovascular disease and can result from other conditions, such as diabetes.

Lipoproteins

• Often referred to as "good" and "bad" cholesterol levels, HDL and LDL aren't just another type of cholesterol. Lipoproteins are cholesterol or triglycerides coupled with special proteins called apolipoproteins. For lipids to move through the bloodstream, they must first attach to these special proteins.

  High-density lipoproteins (HDLs) benefit the body. They resist sticking to artery walls, move easily through the blood, and carry cholesterol back to the liver so that it may be processed out of the body.

  Unstable low-density lipoproteins (LDLs) fall apart easily and the cholesterol they carry doesn't return to the liver. It sticks to and damages artery walls instead. The danger in having high LDL levels is that these damaged artery cells attract fatty clotting substances, which, over time, create artery-blocking plaque.

  A healthy HDL level is 40 or greater, while LDL should be below 100.