It is widely known when much cholesterol circulates in the blood, the risk of heart attack and stroke increases. Some factors that affect blood cholesterol levels are genetics, diet, and exercise.

Cholesterol

Cholesterol is carried in the blood in protein “packages” called lipoproteins. The form of these lipoproteins determines whether the cholesterol is categorized as "good" (HDL) or "bad" (LDL) cholesterol. Excess body fat and a diet high in saturated fat increase LDL levels. Regular exercise, maintaining appropriate body weight, and not smoking help to increase HDL levels. High fiber foods such as oat bran, apples, carrots, oranges, and legumes, decrease cholesterol levels by inhibiting the absorption of cholesterol into the bloodstream. Fish and fish oils, which contain omega-3 fatty acids, also decrease cholesterol levels.

A high-fat/high-cholesterol diet can cause cholesterol to build up in the bloodstream and accumulate in the walls of the blood vessels. Over time the arteries become narrowed, and the flow of blood is reduced, resulting in heart attack or stroke.

Lipoproteins are “packages” of protein and fat which carry cholesterol through the blood. There’s “good cholesterol” (HDL) – which carries cholesterol away from the arteries – and “bad cholesterol” (LDL), which builds up in the blood vessels, as described above. “Bad cholesterol” or LDL levels increase with a diet high in high saturated fat or trans fat and excess body fat. The best ways to increase “good cholesterol” (HDL) are through regular exercise, maintaining appropriate body weight, and not smoking help.

Where does cholesterol come from?

Most of the cholesterol in your blood is manufactured by your liver – about 1,000 mg. each day. The body uses cholesterol to form hormones and cell membranes. In addition, the average American consumes 400 to 600 mg. of cholesterol daily from food. The U.S. Surgeon General's Office and the American Heart Association recommend a maximum intake of 300 mg of cholesterol per day from food.

The cholesterol derived from dietary sources is essentially the same as the cholesterol the body manufactures. Although dietary cholesterol is found only in animal products, excess fat in the diet (especially saturated fat) increases the amount of cholesterol the body produces.

What determines blood cholesterol levels?

1. Genetics.

Some individuals, no matter how prudent their diet or how regularly they exercise, can't achieve a low cholesterol level without the use of blood cholesterol-lowering medications.

2. Diet.

Foods high in saturated fat increase blood cholesterol levels. These include butter, whole milk products, palm and coconut oils, cheese, beef, pork, and egg yolks. In addition, many packaged and processed foods are high in saturated fat or hydrogenated oils, which also have a cholesterol-raising effect.

A diet low in total fat, with fat intake primarily from unsaturated fat sources, reduces cholesterol levels. Unsaturated fats include olive, corn, safflower, sesame, canola, soybean, and sunflower oils. Increasing the consumption of high fiber foods, such as oat bran, apples, carrots, oranges, and legumes (beans, peas and lentils) can be helpful in decreasing the absorption of cholesterol into the bloodstream. Fish and fish oils, which contain omega-3 fatty acids, also decrease cholesterol levels. Read more about the types of fat in the section on fats.

3. Smoking, stress and some medications also raise cholesterol levels.