What exactly is cholesterol?
It's a waxy fat that is present in our bodies. The liver makes most of it. Only about 20 percent comes from the food we eat.

Why does our liver make something that's bad for us?
Cholesterol is not necessarily bad. Our bodies need a certain amount of cholesterol to function. There are different types of cholesterol, some healthy and some unhealthy. Cholesterol is a problem for many people because they have too much of the unhealthy kind.

Which cholesterol is good and which is bad?
Proteins carry cholesterol through the bloodstream. These protein-cholesterol packages are called lipoproteins. They include "good" HDL (high-density lipoproteins), "bad" LDL (low-density lipoproteins) and "very bad" VLDL (very-low-density lipoproteins).

What makes HDL good and other kinds of cholesterol harmful?
HDLs are stable and don't stick to the walls of our arteries. They help prevent heart disease by getting rid of bad cholesterol. LDLs can break apart and stick to the walls of the arteries. They can cause hardening of the arteries (atherosclerosis) and coronary artery disease. Such problems can lead to a stroke or heart attack.

Which foods have cholesterol?
Only animal products (meat, fish, dairy, eggs) contain cholesterol. Note: Foods that don't contain cholesterol aren't necessarily better for you. For example, salmon is far more nutritious than cholesterol-free cookies or chips.

So only animal products can affect my cholesterol?
No. Saturated fats such as coconut oil and vegetable shortening raise LDL. Sugar and other simple carbs can have a negative effect on cholesterol and triglycerides (a type of fatty acid).

What are trans fats?
Trans fatty acids, or trans fats, are present in small amounts in foods such as butter but are most abundant in hydrogenated shortenings. Many processed foods used to be loaded with trans fats but are being reformulated because the U.S. government now requires that food labels list the amount of trans fats.

Why are trans fats dangerous?
They increase bad cholesterol and decrease good cholesterol.

What is "plant cholesterol"?
Phytosterols are vegetable fats whose chemical structure resembles cholesterol. Eating phytosterols may lower LDL cholesterol. These substances are found naturally in foods such as soy, peanuts, peas, rice bran, sunflower seeds, sesame seeds and flaxseed. They are added to some processed foods, such as certain margarines.

So should I add foods with phytosterols to my diet?
For many people, phytosterol-containing foods are healthy ones. But soybeans and flaxseed contain compounds (phytoestrogens) that mimic the effect of the female hormone estrogen. Women at risk of estrogen-related health problems such as breast cancer should talk to their doctor first.

How do I find out what my cholesterol level is?
Basic cholesterol information comes from a simple blood test you can get from your doctor or at health screenings offered at shopping malls, fairs and other such places.

What should my cholesterol level be?
The U.S. government advises a total cholesterol level of less than 200 mg/dL (milligrams per deciliter) and LDL of less than 100 mg/dL. HDL should be at least 40 mg/dL, preferably 60 mg/dL or more.

What is a cholesterol ratio?
That's your total cholesterol divided by your HDL. A general goal is to keep this ratio below five to one, meaning your total cholesterol should be less than five times your good cholesterol.

How can I improve my cholesterol levels?
For decades, the emphasis has been on lowering LDL with low-fat diets and medications. Now some doctors are urging a focus on increasing HDL as well. Ways of improving cholesterol levels include exercising, not smoking, losing extra weight, consuming modest amounts of alcohol (for example, a daily glass of wine) and eating good fats such as olive oil, tuna and other oily fish, nuts, and avocados. In addition to healthy lifestyle changes, your doctor may recommend a cholesterol-lowering drug.