Cholesterol is a sticky, waxy, fatty substance found naturally throughout your body. The body manufactures plenty of cholesterol itself, and cholesterol is also found naturally in foods such as eggs and shellfish. Your body needs it to help you digest other foods and to make hormones and vitamin D.
However, when it comes to cholesterol, too much is not a good thing. When an overload of cholesterol sticks to artery walls, it's referred to as plaque and can block and narrow your arteries. Over time this can lead to atherosclerosis, also known as hardening of the arteries.
If you have a high cholesterol level, your risk for heart disease is increased. There are no warning signs that you have high cholesterol, which tends to increase as you age. But there's a good chance that you have a high cholesterol level if you consume a lot of fatty foods, are overweight, or have a family history of high cholesterol.
Cholesterol moves through your bloodstream inside lipoproteins  little fat (lipid) packages on the inside, with proteins on the outside. Two different kinds of lipoproteins carry cholesterol through the blood:
• High-density lipoprotein (HDL) cholesterol is referred to as good cholesterol. It pushes the fatty substance through your body to the liver, which then removes it from your body. If you have a high HDL cholesterol level, your risk of having heart disease is reduced.
• Low-density lipoprotein (LDL) cholesterol is known as bad cholesterol, because it can lead to an increase of cholesterol in your arteries. If you have high LDL levels of cholesterol in your blood, your risk of having heart disease is increased.
Run the Numbers: LDL vs. HDL
When your doctor orders a blood test to check your cholesterol, you'll get results that include a total (serum) blood cholesterol level, an HDL level, and an LDL level. The American Heart Association provides the following guidance for those levels:
• Total blood (serum) cholesterol level:
o Less than 200 mg/dL is considered desirable
o 200 to 239 mg/dL is considered borderline-high risk
o 240 mg/dL and over is a high risk to your health
• HDL (good) cholesterol level:
o Less than 40 mg/dL for men or less than 50 mg/dL for women means a higher risk for heart disease
o For men, 40 to 50 mg/dL is considered average
o For women, 50 to 60 mg/dL is considered average
If you have an HDL cholesterol of 60 mg/dL or higher, you may have added protection from heart disease.
• LDL (bad) cholesterol level:
o Less than 100 mg/dL is optimal
o 100 to 129 mg/dL is near or above optimal
o 130 to 159 mg/dL is considered borderline high
o 160 to 189 mg/dL is high
o 190 mg/dL and above is considered to be very high
Does having a high level of good cholesterol wipe out the negative effect of having a high level of bad cholesterol? The answer to this may be answered more clearly with future research, but for now the answer is  probably not. High LDL cholesterol levels seem to be a reliable marker for higher heart disease risk in most studies of the general population.
