The Utilization Of Cholesterol
Cholesterol is transported in the plasma predominantly as cholesteryl esters associated with lipoproteins. Dietary cholesterol is transported from the small intestine to the liver within chylomicrons. Cholesterol synthesized by the liver, as well as any dietary cholesterol in the liver that exceeds hepatic needs, is transported in the serum within LDL. The liver synthesizes VLDL and these are converted to LDL through the action of endothelial cell-associated lipoprotein lipase. Cholesterol found in plasma membranes can be extracted by HDL and esterified by the HDL-associated enzyme lecithin-cholesterol acyltransferase, LCAT. The cholesterol acquired from peripheral tissues by HDL can then be transferred to VLDL and LDL via the action of cholesteryl ester transfer protein which is associated with HDL. Reverse cholesterol transport allows peripheral cholesterol to be returned to the liver in LDL. Ultimately, cholesterol is excreted in the bile as free cholesterol or as bile salts following conversion to bile acids in the liver.
What Can Affect My Ldl Level
Things that can affect your LDL level include
- Diet. Saturated fat and cholesterol in the food you eat make your blood cholesterol level rise
- Weight. Being overweight tends to raise your LDL level, lower your HDL level, and increase your total cholesterol level
- Physical Activity. A lack of physical activity can lead to weight gain, which can raise your LDL level
- Smoking.Cigarette smoking lowers your HDL cholesterol. Since HDL helps to remove LDL from your arteries, if you have less HDL, that can contribute to you having a higher LDL level.
- Age and Sex. As women and men get older, their cholesterol levels rise. Before the age of menopause, women have lower total cholesterol levels than men of the same age. After the age of menopause, women’s LDL levels tend to rise.
- Genetics. Your genes partly determine how much cholesterol your body makes. High cholesterol can run in families. For example, familial hypercholesterolemia is an inherited form of high blood cholesterol.
- Medicines. Certain medicines, including steroids, some blood pressure medicines, and HIV/AIDS medicines, can raise your LDL level.
- Other medical conditions. Diseases such as chronic kidney disease, diabetes, and HIV/AIDS can cause a higher LDL level.
- Race. Certain races may have an increased risk of high blood cholesterol. For example, African Americans typically have higher HDL and LDL cholesterol levels than whites.
Medication May Be Needed
For some people, diet and lifestyle changes are not enough. High blood cholesterol levels often have a genetic component. Some people inherit altered genes that cause high cholesterol and this cannot usually be changed sufficiently by lifestyle or diet.
If you are at risk of coronary heart disease and your LDL cholesterol level doesnt drop after scrupulous attention to diet, your doctor may recommend medications to force your blood LDL levels down. Cell cholesterol levels, however, remain normal, so lowering blood cholesterol has no effect on most cell metabolic processes.
Some people get muscle aches from statins, which are the most commonly used medication to lower blood cholesterol. 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.
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How Can I Lower My Cholesterol
If the lifestyle changes alone do not lower your cholesterol enough, you may also need to take medicines. There are several types of cholesterol-lowering drugs available, including statins. If you take medicines to lower your cholesterol, you still should continue with the lifestyle changes.
Some people with familial hypercholesterolemia may receive a treatment called lipoprotein apheresis. This treatment uses a filtering machine to remove LDL cholesterol from the blood. Then the machine returns the rest of the blood back to the person.
NIH: National Heart, Lung, and Blood Institute
What Is Acetyl Coenzyme As Function In The Body
Acetyl Coenzyme A is a processor in your liver which converts nutrients. Its function is to carry out the inter-conversions of nutrients from: carbohydrates, fats, proteins, vitamins, and minerals from your diet, for use as energy. Your bodies essential fat-based substances: cholesterol, triglycerides, phospholipids, eicosanoids , are made by this process. The shortened name of Acetyl Coenzyme A is Acetyl Co-A.
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What Does Cholesterol Do In Your Body
Cholesterol isnt entirely bad for you. In fact, your body uses it to make a few essential hormones, including:
- sex hormones, such as estrogen and progesterone in women, and testosterone in men, which help the sex organs develop and are involved in reproduction
- cortisol, which helps your body respond to stress
- aldosterone, which balances the number of minerals in your body
- vitamin D, which helps your body absorb calcium to strengthen your bones
Cholesterol is also a component of bile, a substance your body needs to digest foods. And its used to build the membrane that surrounds cells.
Cholesterol becomes a problem when you have too much LDL, and too little HDL. LDL bad cholesterol builds up in arteries and forms a sticky goo called plaque .
Over time, plaque hardens blood vessels, making them so rigid that less blood can flow through them. This is called atherosclerosis.
When your arteries are stiff, your heart has to work harder to force blood through them. Over time the heart can get so overworked that it becomes damaged.
Plaques can also break apart, and blood clots can form on the surface.
If a clot becomes lodged in a blood vessel, the clot can cut off your hearts blood supply and cause a heart attack. If a clot instead blocks a blood vessel that supplies your brain, you can have a stroke.
Pharmaceutical Drugs And Niacin
Pharmacological therapy to increase the level of HDL cholesterol includes use of fibrates and niacin. Fibrates have not been proven to have an effect on overall deaths from all causes, despite their effects on lipids.
Niacin increases HDL by selectively inhibiting hepatic diacylglycerol acyltransferase 2, reducing triglyceride synthesis and VLDL secretion through a receptor HM74 otherwise known as niacin receptor 2 and HM74A / GPR109A,niacin receptor 1.
In contrast, while the use of statins is effective against high levels of LDL cholesterol, most have little or no effect in raising HDL cholesterol.Rosuvastatin and pitavastatin, however, have been demonstrated to significantly raise HDL levels.
Lovaza has been shown to increase HDL-C. However, the best evidence to date suggests it has no benefit for primary or secondary prevention of cardiovascular disease.
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The Difference Between Good And Bad Cholesterol
If cholesterol is so necessary, why is it sometimes described as “bad” and at other times as “good?”
Your liver packages cholesterol into so-called lipoproteins, which are combinations of lipids and proteins. Lipoproteins operate like commuter buses that carry cholesterol, other lipids like triglycerides, fat-soluble vitamins, and other substances through the bloodstream to the cells that need them.
- Low-density lipoproteins, sometimes called bad cholesterol, gets its bad reputation from the fact that high levels of it are associated with increasing your risk of heart disease. LDL contains more cholesterol than protein, making it lighter in weight. LDL travels through the bloodstream and carries cholesterol to cells that need it. When it becomes oxidized, LDL can promote inflammation and force lipids to accumulate on the walls of vessels in the heart and rest of the body, forming plaques. These plaques can thicken and may limit or completely block blood and nutrients to affected tissues or organs.
- HDLor high-density lipoproteinsis also commonly referred to as “good cholesterol.” HDL is heavier than LDL because it contains more protein and less cholesterol. HDL gets its good reputation from the fact that it takes cholesterol from the cells and brings it to the liver. Having higher levels of HDL may also help lower your risk of developing cardiovascular disease.
What Complications Are Possible If You Dont Treat High Cholesterol Levels In Your Blood
The main reason to treat high cholesterol is to prevent or treat coronary heart disease , also called coronary artery disease or CAD. CHD happens when heart is not able to get enough oxygen-rich blood to function well and kills more people in the U.S. than any other cause of death. CHD usually refers to the large arteries, but there is also a condition called coronary microvascular disease that affects the small vessels and causes damage.
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Myth: Eating Foods With A Lot Of Cholesterol Will Not Make My Cholesterol Levels Go Up
Fact: It can be complicated. We know that foods with a lot of cholesterol usually also have a lot of saturated fat. Saturated fats can make your cholesterol numbers higher, so its best to choose foods that are lower in saturated fats. Foods made from animals, including red meat, butter, and cheese, have a lot of saturated fats.
Instead, aim to eat foods with plenty of fiber, such as oatmeal and beans, and healthy unsaturated fats, such as avocados, olive oil, and nuts. Learn more about healthy diets and nutrition at CDCs nutrition, physical activity, and obesity website.
Talk with your health care provider about ways to manage your cholesterol. Learn more about medicines to lower cholesterol.
Why Is High Cholesterol So Important
There appears to be an association between elevated cholesterol and risk of premature death from cardiovascular disease.
210 mg/dl is the average cholesterol level for those in developed countries. This level predicts a 50% chance of premature death due to atherosclerosis. Bummer.
Going from 200 mg/dl to 260 mg/dl bumps up chance of death by 500%. The Framingham study showed that no one has died of cardiovascular disease while having a cholesterol level below 150 mg/dl.
Just getting blood cholesterol right under 200 mg/dl might not be enough. 35% of heart attacks that occurred in the Framingham study were in those with normal cholesterol, between 151 mg/dl and 200 mg/dl.
Some have argued that the association between cholesterol and cardiovascular disease, part of a theory of heart disease known as the lipid hypothesis, is minimal at best.
Still, other experts have stated that maintaining a low cholesterol level can protect us against cardiovascular disease.
Regularly maintaining a cholesterol level of less than 150 mg/dl makes one practically heart attack proof and insures against further progression of the disease.Dr. Caldwell Esselstyn
Gosh, it seems like lower is always better. Not so fast.
Some data indicate that low cholesterol levels are associated with depression and cerebral hemorrhage.
While cholesterol seems to play an important role in cardiovascular disease, its definitely not the only factor involved.
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What Happens To Cholesterol And Fat In Your Body
When you eat, cholesterol and fats from the food get broken down in your small intestine. They combine with bile salts, then lipases, and eventually get repackaged with other components before entering the bloodstream as lipoproteins.
Though some cholesterol components are stored in the liver and gallbladder, the main storage area for excess lipoproteins is in fat cells called adipocytes.
When you have too much cholesterol, these cells swell up and you gain weight. Too much cholesterol can be caused by eating too much unhealthy fat or carbohydrates.
Your body also uses some cholesterol to make bile, the greenish-brown fluid your liver produces to aid in food digestion. Bile is stored in your gallbladder.
What Health Problems Can High Cholesterol Cause
If you have large deposits of plaque in your arteries, an area of plaque can rupture . This can cause a blood clot to form on the surface of the plaque. If the clot becomes large enough, it can mostly or completely block blood flow in a coronary artery.
Plaque also can build up in other arteries in your body, including the arteries that bring oxygen-rich blood to your brain and limbs. This can lead to problems such as carotid artery disease, stroke, and peripheral arterial disease.
What Are Normal Levels Of Cholesterol
Normal levels of cholesterol are different depending on your age and sex. These guidelines show desirable total, non-HDL,LDL and HDL levels by age and sex.
Table 1: Target cholesterol levels by age and sex
|Age and sex|
People aged 19 years and younger Men aged 20 years and olderWomen aged 20 years and older
The table above spells out the numbers for normal cholesterol levels. The table below shows you cholesterol levels that are higher than normal. High cholesterol numbers vary by age group and sex, and may be different for those who have heart disease. These guidelines represent high cholesterol numbers for those who do not have heart disease.
Table 2: High total, non-HDL and LDL cholesterol levels by age and sex
|Age and sex|
|People aged 19 years and younger|
Borderline: 170-199 mg/dL
High: Greater than or equal to 200 mg/dL
Borderline: 120-144 mg/dL
High: Greater than or equal to 145 mg/dL
Borderline: 110-129 mg/dL
High: Greater than or equal to 130 mg/dL
High: Greater than or equal to 239 mg/dL
Near optimal or above optimal: 100-129 mg/dL
Borderline high: 130-159 mg/dL
Very high: Greater than 189 mg/dL
High: Greater than or equal to 239 mg/dL
Near optimal or above optimal: 100-129 mg/dL
Borderline high: 130-159 mg/dL
Very high: Greater than 189 mg/dL
LDL cholesterol levels
If you do not have heart disease or blood vessel disease, and you are not at high risk for developing heart disease, the optimal number is less than 100 mg/dL.
What Can Raise My Risk Of High Cholesterol
A variety of things can raise your risk for high cholesterol:
- Age. Your cholesterol levels tend to rise as you get older. Even though it is less common, younger people, including children and teens, can also have high cholesterol.
- Heredity. High blood cholesterol can run in families.
- Weight. Being overweight or having obesity raises your cholesterol level.
- Race. Certain races may have an increased risk of high cholesterol. For example, African Americans typically have higher HDL and LDL cholesterol levels than whites.
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Limit Meat Processed Foods Trans Fats And Dairy
Lots of meat and trans fat seem to be a bad deal for blood cholesterol. Some grass-fed, organic type of meat is fine, but if the factory raised stuff is the foundation of your diet, you may run into cholesterol issues. For trans fat, processed foods and dairy aim for as little as possible to maximize your cholesterol control.
Why Cholesterol Matters
Cholesterol circulates in the blood. As the amount of cholesterol in your blood increases, so does the risk to your health. High cholesterol contributes to a higher risk of cardiovascular diseases, such as heart disease and stroke. Thats why its important to have your cholesterol tested, so you can know your levels.
The two types of cholesterol are: LDL cholesterol, which is bad, and HDL, which is good. Too much of the bad kind, or not enough of the good kind, increases the risk cholesterol will slowly build up in the inner walls of the arteries that feed the heart and brain.
Cholesterol can join with other substances to form a thick, hard deposit on the inside of the arteries. This can narrow the arteries and make them less flexible a condition known as atherosclerosis. If a blood clot forms and blocks one of these narrowed arteries, a heart attack or stroke can result.
When it comes to cholesterol, remember: check, change and control. That is:
- Check your cholesterol levels. Its key to know your numbers and assess your risk.
- Change your diet and lifestyle to help improve your levels.
- Control your cholesterol, with help from your doctor if needed
High cholesterol is one of the major controllable risk factors for coronary heart disease, heart attack and stroke. If you have other risk factors such as smoking, high blood pressure or diabetes, your risk increases even more.
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A View From Evolution
Cholesterol synthesis is an evolutionary very old pathway, so that 7-dehydrocholesterol was already available in early marine organisms, such as phyto- and zooplankton . These species use the photochemical reaction resulting in vitamin D as a protection against UV-B-induced DNA damage, i.e., the historically first role of vitamin D was that of an inert molecule acting as a sunscreen. Since plankton is a major component in the marine food chain, vitamin D accumulates in the liver of many deep-water fish, such as cod. Vitamin D obtained endocrine functions when animals moved out of the water and needed to develop a stable skeleton based on calcium . Therefore, only vertebrates have a full vitamin D endocrine system, composed of plasma transport proteins, such as the vitamin D binding protein, metabolizing enzymes, such as CYP27B1 and CYP24A1, and a specific high-affinity nuclear receptor, such as VDR.
Martin Kohlmeier, in, 2015
Why Is Cholesterol Needed By The Body
With all of the bad publicity cholesterol gets, people are often surprised to learn that its actually necessary for our existence.
Whats also surprising is that our bodies produce cholesterol naturally. But cholesterol isnt all good, nor is it all bad its a complex topic and one worth knowing more about.
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