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Heart Disease: How To Reduce The Risk

What You Should Know About Cholesterol

Thursday, March 29, 2012 - 22:00

Contributing Author: Guy Slowik FRCS

Cholesterol is necessary for our bodies to function, and it is found in every cell in our body. About 80 percent of the cholesterol in our bodies is manufactured by the liver, while the other 20 percent comes from the foods that we eat.

However, a diet high in cholesterol can cause our bodies to make too much cholesterol, resulting in high levels of blood cholesterol. When blood cholesterol levels get too high, it can clog arteries and increase our risk for coronary heart disease.

What is cholesterol?

How does high cholesterol increase your risk of coronary heart disease?

The different types of cholestero

What affects blood cholesterol levels?

Do all types of fats raise blood cholesterol levels?

Does cholesterol in foods raise blood cholesterol?

What Is Cholesterol?

Cholesterol is a waxy substance that is made in our bodies by the liver. Cholesterol forms part of every cell in the body. Our bodies need cholesterol to:

  • Maintain healthy cell membranes
  • Make hormones
  • Make vitamin D
  • Make bile acids, which aid in fat digestion

Sometimes, however, our bodies make too much cholesterol. When we eat too much saturated fat - the kind of fat found in hardened fat products like most margarines, vegetable shortening, and animal-based foods such as meat and dairy products - our bodies can make too much cholesterol.

We also get cholesterol from the foods we eat. Only animal-based foods such as meat, eggs, and dairy products contain cholesterol. Plant foods do not contain cholesterol.

How Does High Cholesterol Increase Your Risk For Heart Disease?

When we get too much cholesterol - either because our body makes too much or because we eat too many foods rich in saturated fat - the surplus cholesterol circulates in the bloodstream.

  • Deposits of cholesterol and other fat-like substances can build up in the inner lining of these blood vessels and become coated with scar tissue, forming a cholesterol-rich bump in the blood vessel wall known as plaque.
  • Plaque build-up narrows and hardens the blood vessel; a process called atherosclerosis, or hardening of the arteries.

Need To Know:

A high blood cholesterol level is especially dangerous for smokers and those with high blood pressure.

The Different Types Of Cholesterol

Cholesterol travels through the body in packages called lipoproteins, which consist of cholesterol and proteins. Some lipoproteins contain another type of fat, called triglycerides.

  • High-density lipoproteins (HDLs) contain mostly protein
  • Low-density lipoproteins (LDLs) contain mostly cholesterol
  • Very-low-density lipoproteins (VLDLs) contain mostly cholesterol and triglycerides.

Not all cholesterol is harmful. High-density lipoprotein (HDL) cholesterol is a good type of cholesterol that actually helps to remove cholesterol from the walls of arteries and transports it to the liver for elimination. HDL cholesterol helps the body get rid of low-density lipoprotein (LDL) cholesterol and very-low-density lipoprotein (VLDL) cholesterol, the bad types of cholesterol that are most likely to clog blood vessels.

LDL and VLDL are commonly known as "bad" cholesterol and HDL as "good" cholesterol.

Need To Know:

You should also have your blood level of another type of fat, triglycerides, measured at the same time you have your blood cholesterol levels checked. High blood triglyceride levels can also increase risk for coronary heart disease. Fortunately, these levels can be quickly lowered with weight control and more exercise.

What Affects Blood Cholesterol Levels?

Many things affect the cholesterol level in your blood:

  • What you eat: You can lower your cholesterol level by cutting down on animal fat and other fats and eating foods rich in starch and fiber, such as fresh fruits, vegetables, and whole grains.
  • Your hormones: Women get a natural boost in their HDL cholesterol from their hormones until they reach menopause. After menopause, taking estrogen can help maintain higher HDL cholesterol ("good" cholesterol) levels.
  • Medications: For most people, diet and exercise is the best way to control cholesterol levels. For some individuals, doctors may prescribe medication to reduce blood cholesterol levels, especially if high levels of cholesterol run in your family.
  • Other factors: Being overweight, inactive, and smoking all increase levels of the harmful type of cholesterol.

Do All Types Of Fats Raise Blood Cholesterol Levels?

There are three main types of fats in food:

  • Saturated fat: A type of fat found in animal foods like beef, pork, lamb, and dairy products; in tropical oils such as palm and coconut oil; and in vegetables oils that have been chemically changed to make them solid at room temperature (a process called hydrogenation).
  • Monounsaturated fat: A type of fat found in plant oils such as olive oil and canola oil.
  • Polyunsaturated fat: A type of fat found in plant oils such as safflower, sunflower, corn, or soybean oil.

Although all fats are concentrated sources of calories and can contribute to weight gain (and thus, high blood cholesterol levels), saturated fat is the most harmful. Saturated fat is the main cause of high blood cholesterol levels. When you eat it, your body may react by making more cholesterol than it needs, and the surplus ends up in your blood.

Nice To Know:

Fish, especially cold water fish, contain a special type of polyunsaturated fat called omega-3 fat that may help protect against coronary heart disease by slowing blood clotting.

Does Cholesterol In Foods Raise Blood Cholesterol?

Although a diet high in saturated fat is the main cause of high blood cholesterol levels, high cholesterol in the diet can also raise blood cholesterol levels.

Like people, animals also make cholesterol and carry cholesterol throughout their bodies. If we eat meat or dairy products, we cannot avoid cholesterol. If you eat modest amounts of lean meats and dairy products, your cholesterol intake will not be too high. However, you should limit foods such as egg yolks and liver, which contain high amounts of cholesterol.

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