TIWhat is cholesterol?
Cholesterol is a fatty substance (a ) that is an important part of the outer lining (membrane) of cells in the body of animals. Cholesterol is also found in the blood circulation of humans. The cholesterol in a person's blood originates from two major sources; dietary intake and liver production. Dietary cholesterol comes mainly from meat, poultry, fish, and dairy products. Organ meats, such as liver, are especially high in cholesterol content, while foods of plant origin contain no cholesterol. After a meal, cholesterol is absorbed by the intestines into the blood circulation and is then packaged inside a coat. This cholesterol-protein coat complex is called a .
The liver is capable of removing cholesterol from the blood circulation as well as manufacturing cholesterol and secreting cholesterol into the blood circulation. After a meal, the liver removes chylomicrons from the blood circulation. In between meals, the liver manufactures and secretes cholesterol back into the blood circulation.
What are LDL and HDL cholesterol?
LDL cholesterol is called "bad" cholesterol, because elevated levels of LDL cholesterol are associated with an increased risk of . LDL lipoprotein deposits cholesterol on the artery walls, causing the formation of a hard, thick substance called cholesterol plaque. Over time, cholesterol plaque causes thickening of the artery walls and narrowing of the arteries, a process called .
HDL cholesterol is called the "good cholesterol" because HDL cholesterol particles prevent atherosclerosis by extracting cholesterol from the artery walls and disposing of them through the liver. Thus, high levels of LDL cholesterol and low levels of HDL cholesterol (high LDL/HDL ratios) are risk factors for atherosclerosis, while low levels of LDL cholesterol and high level of HDL cholesterol (low LDL/HDL ratios) are desirable.
Total cholesterol is the sum of LDL (low density) cholesterol, HDL (high density) cholesterol, VLDL (very low density) cholesterol, and IDL (intermediate density) cholesterol.
What determines the level of LDL cholesterol in the blood?
The liver not only manufactures and secretes LDL cholesterol into the blood; it also removes LDL cholesterol from the blood. A high number of active LDL receptors on the liver surfaces is associated with the rapid removal of LDL cholesterol from the blood and low blood LDL cholesterol levels. A deficiency of LDL receptors is associated with high LDL cholesterol blood levels.
Both heredity and diet have a significant influence on a person’s LDL, HDL and total cholesterol levels. For example, (FH) is a common inherited disorder whose victims have a diminished number or nonexistent LDL receptors on the surface of liver cells. People with this disorder also tend to develop atherosclerosis and heart attacks during early adulthood.
Diets that are high in saturated fats and cholesterol raise the levels of LDL cholesterol in the blood. Fats are classified as saturated or unsaturated (according to their chemical structure). Saturated fats are derived primarily from meat and dairy products and can raise blood cholesterol levels. Some vegetable oils made from coconut, palm, and cocoa are also high in saturated
What are “normal” cholesterol blood levels?
There are no established “normal” blood levels for total and LDL cholesterol. In most other blood tests in medicine, normal ranges can be set by taking measurements from large number of healthy subjects. For example, normal fasting blood sugar levels can be established by performing blood tests among healthy subjects without mellitus. If a patient’s fasting blood falls within this normal range, he/she most likely does not have , whereas if the patient’s fasting blood sugar tests higher than the normal range, he/she probably has diabetes mellitus and further tests can be performed to confirm the diagnosis. Medications, such as or oral diabetes medications can be prescribed to lower abnormally high blood sugar levels.
Unfortunately, the normal range of LDL cholesterol among “healthy” adults (adults with no known coronary heart disease) in the United States may be too high. The atherosclerosis process may be quietly progressing in many healthy adults with average LDL cholesterol blood levels, putting them at risk of developing coronary heart diseases in the future.
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Cholesterol doesn’t kill, ignorance does
Why High Blood Cholesterol Is Dangerous
Cholesterol, like fat, cannot move around the bloodstream on its own because it does not mix with water. The bloodstream carries cholesterol in particles called lipoproteins that are like blood-borne cargo trucks delivering cholesterol to various body tissues to be used, stored or excreted.
But too much of this circulating cholesterol can injure arteries, especially the coronary ones that supply the heart. This leads to accumulation of cholesterol-laden “plaque” in vessel linings, a condition called atherosclerosis.
When blood flow to the heart is impeded, the heart muscle becomes starved for oxygen, causing chest pain (angina). If a blood clot completely obstructs a coronary artery affected by atherosclerosis, a heart attack (myocardial infarction) or death can occur.
Are you at risk? Cardiovascular disease is still one of the greatest health problem affecting western countries. According to the American Heart Foundation, over 70 million Americans have cardiovascular disease (CVD). The national cost of is nearly $400 billion and every 45 seconds an American has a stoke.
Certain risk factors increase your chances of developing cardiovascular disease.
* High blood cholesterol
* Insufficient physical activity
* High blood pressure
* Excessive alcohol intake
Many people have multiple risk factors for heart disease and the level of risk increases with the number of risk factors. By reducing these risk factors you can largely prevent the onset of cardiovascular disease. On its own elevated blood cholesterol is not necessarily a problem, but coupled with one or more other risk factors for heart disease, it is often the straw that breaks the camel’s back.
It is, therefore, very important to know what your cholesterol levels are and to keep them at a healthy level before you have any problems.
High risk cholesterol
If your total cholesterol level is 240 or more, it's definitely high. You have a higher risk of heart attack and stroke. In fact, you should have your LDL and HDL cholesterol tested. Ask your doctor for advice. Close to 20 percent of the U.S. population has high blood cholesterol levels.
People whose total cholesterol is 200 to 239 mg/dL have borderline-high cholesterol. About a third of American adults are in this group, while almost half of adults have total cholesterol levels below 200 mg/dL. In fact, people who have a total cholesterol of 240 mg/dL have twice the risk of coronary heart disease as people whose cholesterol level is 200 mg/dL. Does physical activity affect cholesterol?
Other factors that affect blood cholesterol levels:
Heredity – High cholesterol often runs in families. Even though specific genetic causes have been identified in only a minority of cases, genes still play a role in influencing blood cholesterol levels. If your parents have high cholesterol, you need to be tested to see if your cholesterol levels are also elevated.
Age and gender – Before menopause, women tend to have total cholesterol levels lower than men at the same age. Cholesterol levels naturally rise as men and women age. Menopause is often associated with increases in LDL cholesterol in women.
Stress – Studies have not shown stress to be directly inked to cholesterol levels. But experts say that because people sometimes eat fatty foods to console themselves when under stress, this can cause higher blood cholesterol.
Excess weight – Being overweight tends to increase blood cholesterol levels. Losing weight has been shown to help lower levels. A greater risk of increased cholesterol levels occurs when that extra weight is centred in the abdominal region, as opposed to the legs or buttocks.
- Source: Adapted From Herbalife Today Magazine
Further articles on cholesterol:
How to Lower Your Cholesterol
Healthy eating can do wonders for your cholesterol levels. The healthy eating messages below are from the brochure called: Enjoy Healthy Eating: a guide to keeping your blood cholesterol in check.
Use margarine spreads instead of butter or dairy blends.
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Don’t cut out all dairy foods
Some people believe that cutting out dairy foods altogether is the safest option, but this isn’t true. Dairy foods are an important part of the daily diet and contribute many essential nutrients, especially calcium. You should switch to low fat types, which will reduce the risk from saturated fats.
You don’t need to avoid eggs and seafood
Some foods are high in cholesterol but they’re fine to eat in moderation, as long as your overall diet is low in saturated fats. For example:
Some studies have suggested that eating oats and legumes may lower LDL cholesterol. Food components like saponins (found in chickpeas, alfalfa sprouts and other foods) and sulphur compounds (like allicin – found in garlic and onions) may also have a positive effect on cholesterol levels.
Plant sterols can lower cholesterol levels
Plant sterols are found naturally in plant foods including sunflower and canola seeds, vegetable oils and (in smaller amounts) in nuts, legumes, cereals, fruit and vegetables. Some margarine has concentrated plant sterols added to it. Plant sterol enriched margarines may help to lower LDL cholesterol.
Medication may be needed
For some people diet and lifestyle changes are not enough. High blood cholesterol levels are also linked to genetics. Some people inherit altered genes that cause high cholesterol, and this can usually not be changed by lifestyle or diet.
If you are at risk of coronary heart disease and your LDL cholesterol level doesn’t drop after scrupulous attention to diet, your doctor may recommend medications to force your LDL levels down. However, diet and exercise will still be important, even if you are taking medication. Your doctor may also refer you to a specialist who treats cardiovascular disease.
Where to get help