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Chiming in on Cholesterol |
What's all the talk about Cholesterol these days? It's a major topic of conversation…and confusion these days, but here's what rings true:
Cholesterol is a soft, waxy substance found among the lipids (fats) in the bloodstream and in all body cells. It's essential to healthy bodies because it's transmitted through the blood and used to form cell membranes and some hormones.
However, a high level of Cholesterol in the blood can lead to a 911 emergency. It can overload the body's circulatory system and cause coronary heart disease, which leads to heart attack. Since Cholesterol and other fats can't dissolve in the blood, the build-up deprives the heart of the blood and oxygen it needs to function properly and efficiently.
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How?
Think of the heart as a phone, arteries as a cell tower and Cholesterol as the phone calls.Too many phone calls (too much Cholesterol) going into the cell tower (the arteries) will overload the system and prevent all the calls from going through to the phone line (the heart). The result: An "All circuits are busy" message. When Cholesterol and fats clog the arteries, the same thing occurs; causing a heart attack and/or stroke since rich, oxygenated blood is blocked from getting through.
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In the bloodstream, Cholesterol and fats are transported to and from the cells by special carriers called lipoproteins. There are several kinds of Cholesterol, but the ones to focus on are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).
What is LDL Cholesterol? (A Bad Cell Signal)
A bad cell signal is not only for cell phones, it can also apply to Low-Density Lipoprotein (LDL), the major Cholesterol carrier in the blood. If too much LDL Cholesterol circulates in the blood, it can slowly build up in the walls of the arteries that feed the heart and brain. Together with other substances it can form plaque, a thick, hard deposit that can clog those arteries. This condition is known as atherosclerosis. A clot that forms near this plaque can block the blood flow to part of the heart muscle and cause a heart attack. If a clot blocks the blood flow to part of the brain, a stroke results.
A high level of LDL Cholesterol reflects an increased risk of heart disease. That's why LDL Cholesterol is called "bad" Cholesterol. Lower levels of LDL Cholesterol reflect a lower risk of heart disease.
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What is HDL Cholesterol? (A Good Cell Signal)
About one-third to one-fourth of blood Cholesterol is carried by HDL. Medical experts think HDL tends to carry Cholesterol away from the arteries and back to the liver, where it's passed from the body. Some experts believe HDL removes excess Cholesterol plaques and thus slows their growth. HDL Cholesterol is known as "good" Cholesterol because a high HDL level seems to protect against heart attack. The opposite is also true: a low HDL level indicates a greater risk. A low HDL Cholesterol level also may raise stroke risk.
What is Lp(a) Cholesterol?
Lp(a) is a genetic variation of plasma LDL. A high level of Lp(a) is an important risk factor for developing atherosclerosis prematurely. How an increased Lp(a) contributes to heart disease isn't clear. The lesions in artery walls contain substances that may interact with Lp(a), leading to the buildup of fatty deposits.
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People get Cholesterol in two ways.
- The body — mainly the liver —which is often influenced by heredity, produces varying amounts, usually about 1,000 milligrams a day
- Foods. Animal foods contain Cholesterol - Especially egg yolks, meat, poultry, fish, seafood and whole-milk dairy products
Plant foods do not contain Cholesterol - For example, fruits, vegetables, grains, nuts and seeds.
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- Individuals with a family history of high Cholesterol
- People who don't eat the RDA of fruits and vegetables
- People making poor food choices or having unhealthy eating habits
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Sources:
USDA - Nutrient Data Lab (Sept. 1996)
USDA School Meals Initiative for Healthy Children
US Dept of health and Human Services, Guidelines for School health programs to Promote Lifelong Healthy Eating, June 1996
CNN.com, Food Resource Planner
2004 President and Fellows of Harvard College.
AHA Science Advisory: Stanol/Sterol Ester-Containing Foods and Blood Cholesterol Levels, #71-0201 Circulation. 2001;103:1177
Physicians Committee for Responsible Medicine, School Lunch Report, August 2004
WebMD Health
National Institutes of Health, Office of Dietary Supplements
AHA Conference Proceedings: Summary of the Scientific Conference on Dietary Fatty Acids and Cardiovascular Health, #71-0200 Circulation. 2001;103:1034-1039
Journal of Epidemiology (May, 1992)
The Vitamin and Nutrition Center, 2004 |
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