During my university years, one of my friends used to frustrate his parents by throwing away egg yolks and eating only the whites. He thought that he was reducing the risk of heart disease by avoiding cholesterol. How about you? Are you afraid of cholesterol or having high cholesterol? Are you throwing away egg yolks because you think they're bad for your health?
Let’s learn more about cholesterol. Cholesterol is a chemical compound that is naturally produced by the body and is structurally a combination of lipid (fat) and steroid. Cholesterol is a building block for cell membranes and for hormones like estrogen and testosterone. The main sources of dietary cholesterol are 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.
Cholesterol is not a deadly poison, but a substance that you need to be healthy. High cholesterol itself does not cause heart disease. People who have low blood cholesterol have the same rates of heart disease as people who have high blood cholesterol. The cholesterol found in your blood comes from two sources: cholesterol in food that you eat and cholesterol that your liver makes from other nutrients. The amount of cholesterol that your liver produces varies according to how much cholesterol you eat. Normally, liver produces 75% of the cholesterol that circulates in our blood. The other 25% comes from food. If you eat a lot of cholesterol, your liver produces less. After a meal, dietary cholesterol is absorbed from the intestine and stored in the liver. If you don't eat much cholesterol, your liver produces more. This is why a low cholesterol diet does not typically decrease a person's blood cholesterol by more than a few percent.
Types of Cholesterol
There are two types: Bad" and "Good" Cholesterol. Particles called lipoproteins carry cholesterol in the blood. There are two kinds of lipoproteins you need to know about: LDL and HDL.
Low-density lipoproteins (LDL) cholesterol makes up the majority of the body's cholesterol. LDL is known as "bad" cholesterol because having high levels can lead to a buildup in the arteries and result in heart disease. It is very important to keep LDL levels low. LDLs are produced by the liver and carry cholesterol and other lipids (fats) from the liver to different areas of the body, like muscles, tissues, organs, and the heart.
High-density lipoproteins (HDL) cholesterol absorbs cholesterol and carries it back to the liver, which flushes it from the body. High levels of HDL, or "good" cholesterol, reduce the risk of heart disease and stroke.
Very low density lipoproteins (VLDL) are lipoproteins that carry cholesterol from the liver to organs and tissues in the body. They are formed by a combination of cholesterol and triglycerides. VLDLs are heavier than low density lipoproteins, and are also associated with atherosclerosis and heart disease.
What Boosts Your Risk?
Several health factors, lifestyle and genetic factors can make you more likely to develop high cholesterol:
• Condition
– Age: everyone's risk for high cholesterol increases with age. Women's LDL ("bad" cholesterol) levels rise more quickly than do men's.
– Diabetes: Having diabetes can also make you more likely to develop high cholesterol. Diabetes affects the body's use of a hormone called insulin. This hormone tells the body to remove sugar from the blood. With diabetes, the body either doesn't make enough insulin, can't use its own insulin as well as it should, or both. This causes sugars to build up in the blood.
• Behavior
– Diet: Certain foods raise your cholesterol levels. These foods tend to contain saturated fats, trans fatty acids (trans fats), dietary cholesterol, or triglycerides.
– Weight: being overweight can raise LDL, lower HDL, and raise total cholesterol levels.
– Physical inactivity: Not getting enough exercise can make you gain weight, which can lead to increased cholesterol levels.
• Heredity
High cholesterol can run in families. People who have an inherited genetic condition, called familial hypercholesterolemia, have very high LDL cholesterol levels beginning at a young age.
Diseases linked to high cholesterol
Diseases linked to high cholesterol
• Coronary heart disease: If your cholesterol is too high, it builds up on the walls of your arteries. Over time, this buildup (called plaque) causes hardening of the arteries (atherosclerosis).
• Stroke can result if the blood supply to part of the brain is reduced.
• Peripheral vascular disease: High cholesterol also has been linked to peripheral vascular disease (PAD), which refers to diseases of blood vessels outside the heart and brain.
• Type 2 diabetes is another disease linked to high cholesterol because diabetes can affect the different cholesterol levels.
• High blood pressure (hypertension) and high cholesterol also are linked.
• Leriche syndrome: there is a block in the lower part of the aorta just before the starting point of the common iliac arteries leading to Claudication, Impotence and Decreased pulses
Diseases linked to low cholesterol
• American researchers found that low cholesterol predicts an increased risk of dying from diseases of the stomach, the intestines and the lungs. Most of such diseases are infectious.
• Low Cholesterol Predisposes To HIV And AIDS
• Low cholesterol levels have been shown to increase the risk for cancer.
• Low cholesterol over the long term may lead to depression, increased risk of stroke, and numerous problems related to hormonal imbalances. If you are not getting enough vitamin D from your diet, having low cholesterol may lead to vitamin D deficiency, as sunlight creates vitamin D in your body by acting on cholesterol found in your skin.
• Smith-Lemli-Opitz Syndrome: children with this syndrome are born with very low cholesterol because an enzyme that is necessary for the body’s synthesis of cholesterol does not function properly.
The Positive Roles of Cholesterol
Actually, cholesterol is essential for survival and plays many vital roles in the body.
• Cholesterol is integral part of membranes and membrane integrity depends on the obligate presence of cholesterol.
• Cholesterol is required for the synthesis of several hormones including the sex hormones.
• Vitamin D is synthesized in the body from cholesterol and it is now known that the roles of vitamin D go beyond bone formation.
• Bile salts are essential for the digestion of the fats consumed and this compound is also produced from cholesterol.
• Cholesterol is anti-inflammatory.
• Cholesterol’s presence is required for the normal functioning of the serotonin receptors. Since serotonin is a mood elevator, low cholesterol levels produce aggressive behaviour and mood swings.
Now the question is do you need Cholesterol? Definitely, you do. The cholesterol is an essential biological molecule present in our body and survival without this compound, is not possible.
The cholesterol is required to form the bile acids and salts, required to digest the fats which you consume. A wide variety of steroid hormones are produced, with the cholesterol as the precursor. It also leads to the formation of vitamin D, required for keeping your bones healthy. So, don’t be afraid of cholesterol. It is a problem only when you have more than what is needed by you.
The essential point is we need to keep ourselves healthy and not just get treated when we our cholesterol levels go badly. I am working as a Bioinformatician in INFOVALLEY since more than four years and was involved in the FH project which resulted in a high density FH1536 chip which is able to diagnose the molecular basis of Hypercholesterolemia, screening for at risk individuals, prognostic about the heart attack and stroke and also advise the doctor the most appropriate medicine. FH genotyping screening can be undergone by subjects of all ages.
Reference:
http://www.medicinenet.com/cholesterol/page2.htm#what_is_cholesterol
http://www.ravnskov.nu/the%20benefits%20of%20high%20C.htm
http://vnsatakopan.hubpages.com/hub/Does-Cholesterol-Deserve-All-the-Blame-it-Gets
http://www.ravnskov.nu/cholesterol.htm#a
http://drbenkim.com/articles-cholesterol.html
http://www.medicinenet.com/cholesterol_levels_pictures_slideshow/article.htm
By Kavitha IS, Bioinformatician
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