Cholesterol is a combination of two acetate molecules that join to form a waxy substance. It is found in animals because it's produced by the liver. Plants do not have any cholesterol.

It is needed by the body to produce hormones and steroids and is used in the production of cell membranes. We need cholesterol to live.

But the amount of cholesterol in our bodies, and the balance between the two main types of cholesterol and other molecules like homocysteine, triglycerides, and free radicals, can predict whether we are at risk for diseases like atherosclerosis, heart disease, or stroke. Too much of the wrong kind of cholesterol can increase the risk of disease. And the way cholesterol interacts with other substances in the body increases disease risk, too.

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Cholesterol must combine with a protein and a fat in order to travel through the bloodstream. These combinations of molecules are called lipoproteins. There are two main types of lipoproteins: high-density and low-density (also known as HDL and LDL).

Total cholesterol levels of up to 200 mg/dL (milligrams per decaliter) are considered normal. Depending on your health and other risk factors, your doctor may want this level to be lower. If your level falls between 200 and 239 mg/dL, you'll want to evaluate your LDL/HDL ratio. The American Heart Association has different recommendations for tests and treatment depending on the combination of these factors.

Cholesterol levels will vary depending on your genetics, age, and even gender. The levels rise as we age. Men usually have higher levels than premeno-pausal women, but after menopause women's cholesterol counts increase.

HDL Cholesterol

HDL, or high density lipoprotein, is known as the “good” cholesterol because it removes LDL cholesterol from the bloodstream and takes it to the liver to be metabolized into bile salts and excreted. This type of cholesterol may actually scour your arteries, helping remove LDL cholesterol and reducing atherosclerosis and plaque formation. Here are some foods that increase HDL levels:

• Olive oil

• Nuts

• Avocados

• Peanut butter

• High-fiber foods

• Moderate alcohol consumption

• Dried beans

• Whole grains

• Citrus fruits

• Dark chocolate

For a healthy body, your HDL cholesterol levels should be above 40 mg/dL. Fortunately, your diet and lifestyle, including the right foods and exercise, can have a significant impact on HDL levels.

LDL Cholesterol

LDL, or low density lipoprotein, is known as the “bad” cholesterol because it transports cholesterol from the liver to the bloodstream. Research indicates that plaque, which can form on arterial walls and narrow the arteries, may be filled with LDL cholesterol. Here are some foods that reduce LDL levels:

• Oatmeal and oat bran

• Orange juice

• Apples

• Walnuts and almonds

• Flaxseed

• Fatty fish

• Legumes

• Barley

• Cherries

• Vegetables

Your LDL cholesterol levels should be less than 100 mg/dL. Over 160 mg/dL is considered high. The level of this type of cholesterol responds well to changes in diet and the addition of exercise.

The Total/HDL Cholesterol Proportion

The proportion of total cholesterol to HDL in your blood is an important risk predictor for heart disease. To calculate this, divide your total cholesterol level by your HDL level. The ratio you want to reach is below 3.5 to 1. Anything about 5 to 1 or higher indicates an increased risk of heart disease.