Your body needs a certain amount of cholesterol to function properly but high cholesterol levels in your bloodstream can lead to health problems. More than 100 million American adults had high cholesterol levels in 2010, according to the Centers for Disease Control and Prevention. More than 35 million of those people had levels high enough to put them at risk for heart disease. You can reduce your cholesterol and your risk for heart disease and other medical conditions.
Function
Cholesterol is a naturally-occurring substance and a necessary component in the production of bile acids used in digestion. Bile production accounts for most of the cholesterol in your body; very little cholesterol enters the bloodstream. Cholesterol is present in the structure of every cell membrane. Your body uses cholesterol to create skin oils, hormones such as estrogen and testosterone, and to metabolize vitamins A, D, E and K.
Source
Your liver creates most of the bile in your body. You gained the rest through the foods you consume. People do not need to eat cholesterol for the body to function properly- the liver would simply produce more to make up the difference. Animals produce cholesterol in their livers. Only animal products, like meat, eggs, milk and cheese contain cholesterol. Food made only from plant sources does not contain cholesterol.
Lipoproteins
Cholesterol moves from the liver to the cells of the body via the bloodstream. Cholesterol is a lipid, which is a fat-like substance that does not dissolve well into the watery plasma of blood. The body overcomes this by packaging lipids onto special proteins to create lipoproteins, capable of moving well through the bloodstream. Low-density lipoproteins carry cholesterol from the gut to the awaiting cells, thusly earning its reputation for causing heart disease by introducing more cholesterol into the bloodstream. High-density lipoproteins, or HDL, scrape cholesterol from arterial walls and carry it back to the liver, where it is processed and eliminated from the body.
High Cholesterol
A poor diet including an excessive amount of fat and cholesterol is the primary reason for high blood cholesterol levels. High levels of cholesterol in the bloodstream are closely associated with increased risk for heart disease. Excess cholesterol accumulates in the bloodstream and builds up inside blood vessels. This accumulation injures blood vessels and prevents oxygen-rich blood from reaching vital organs, like the heart, brain and kidneys.
Risks
High blood cholesterol levels are associated with several medical conditions, including heart disease and kidney disease. Every 1 percent drop in blood cholesterol levels reduces risk for heart disease by 2 percent, according to Cleveland Clinic. The Fisher Center for Alzheimer's Research Foundation cites a study by Kaiser Permanente that links mildly elevated cholesterol levels in midlife with Alzheimer's in later years. The Kaiser Permanente study shows cholesterol levels as low as 220 mg/dL increases risk for Alzheimer's.
