cholesterol (redirected from Understanding Cholesterol)

cholesterol /cho·les·ter·ol/ (kah-les´ter-ol) a eukaryotic sterol that in higher animals is the precursor of bile acids and steroid hormones and a key constituent of cell membranes. Most is synthesized by the liver and other tissues, but some is absorbed from dietary sources, with each kind transported in the plasma by specific lipoproteins. It can accumulate or deposit abnormally, as in some gallstones and in atheromas. Preparations are used as emulsfiers in pharmaceuticals.

Structure and metabolism of cholesterol.

---

HDL cholesterol , high-density–lipoprotein cholesterol (HDL-C) the serum cholesterol carried on high-density lipoproteins, approximately 20 to 30 per cent of the total.

LDL cholesterol , low-density–lipoprotein cholesterol (LDL-C) the serum cholesterol carried on low-density lipoproteins, approximately 60 to 70 per cent of the total.

---

cho·les·ter·ol (k-lst-rôl, -rl)

n.

A white crystalline substance found in animal tissues and various foods, normally synthesized by the liver and important as a constituent of cell membranes and a precursor to steroid hormones. Its level in the bloodstream can influence the pathogenesis of certain conditions, such as the development of atherosclerotic plaque and coronary artery disease.

---

Cholesterol

A fat-like substance that is made by the human body and eaten in animal products. Cholesterol is used to form cell membranes and process hormones and vitamin D. High cholesterol levels contribute to the development of atherosclerosis.

Mentioned in: Atherosclerosis, Cholesterol-Reducing Drugs, Hypolipoproteinemia, Lipoproteins Test, Rickets, Vitamin D Deficiency

---

cholesterol

[kəles′tərôl]

Etymology: Gk, chole + steros, solid

a waxy lipid soluble compound found only in animal tissues. A member of a group of compounds called sterols, it is an integral component of every cell in the body. It facilitates the absorption and transport of fatty acids. Cholesterol acts as the precursor for the synthesis of various steroid hormones, including cortisol, cortisone, and aldosterone in the adrenal glands, and of the sex hormones progesterone, estrogen, and testosterone. It sometimes precipitates along with other compounds in the gallbladder to form gallstones. Cholesterol is found in foods of animal origin and is continuously synthesized in the body, primarily in the liver. Increased levels of low-density lipoprotein cholesterol may be associated with the pathogenesis of atherosclerosis, whereas higher levels of high-density lipoprotein cholesterol appear to lower the person's risk for heart disease. Normal adult levels of blood cholesterol are 150 to 200 mg/dL or 3.9 to 5.2 mmol/L (SI units). Also called cholesterin. See also high-density lipoprotein, low-density lipoprotein, sterol.

---

cholesterol (k·lesˑ·ter·l),

n organic compound produced in the liver and absorbed from food that is essential to the production of metabolic products and hormones.

Cholesterol.

---

cholesterol (kles´trôl),

n a lipid common to all animal, but not plant, cells. As a sterol, it contains the cyclopentanophenanthrene nucleus. High levels are found in nerve tissue, atheromas, gallstones, and cysts. Normally 140 to 220 mg are present in 100 ml of blood.

---

cholesterol

a steroid alcohol found in animal fats and oils, bile, blood, brain tissue, milk, egg yolk, myelin sheaths of nerve fibers, liver, kidneys and adrenal glands. It is a necessary component of all cell surface and intracellular membranes and a constituent of myelin in nervous tissue; it is a precursor of bile acids and steroid hormones, and it occurs in the most common type of gallstone, in atheroma of the arteries, in various cysts, and in carcinomatous tissue. Most of the body's cholesterol is synthesized, but some is obtained in the diet.

The preoccupation in human medicine with the relationship between cholesterol and the development of atheromatous plaques in the coronary arteries is not reflected in veterinary medicine. The importance of cholesterol to the veterinarian is limited to the measurement of blood cholesterol levels as an indicator of liver disease or thyroid activity.

---

cholesterol pneumonia

see endogenous-lipid pneumonia.

---

cholesterol

Biochemistry A precursor of steroid hormones and bile acids; it is an integral component of cell membranes and plasma lipoproteins, and found in animal fats, bile, blood, brain, milk, egg yolk, myelin sheaths, liver, kidneys, and adrenal glands; it is absorbed from the diet and synthesized in the liver; diets high in saturated–animal fats ↑ cholesterol levels; it is the main component of the most common type of gallstones, and integral to arterial atheromas, in cysts and in malignancy; it is a precursor of bile acids and important in the synthesis of steroid hormones; diets low in saturated fats ↓ cholesterol levels, as does exercise; ↑ cholesterol is associated with ASHD, CAD, ↑ risk of death due to acute MIs and strokes; total cholesterol–TC is measured in routine chemistry panels; cholesterol is transported in the circulation by carrier proteins, which are classified according to their density–high-density lipoprotein—HDL, LDL, VLDL, based on density gradient ultracentrifugation; HDL-C is metabolized efficiently, and thus is 'good' cholesterol; 'bad cholesterol,' LDL-C, is inefficently metabolized High risk for ASHD TC > 6.21 mmol/L–US > 240 mg/dL; LDL-C > 160 mg/dl, HDL-C
< 35 mg/dl Borderline risk 5.17-6.18 mmol/L–US: 200-239 mg/dL Low risk < 5.17 mmol/L–US 200 mg/dL, LDL-Cl < 130 mg/dL, HDL-C > 55 mg/dL ↑ in Hypercholesterolemia, nephrotic syndrome, hypothyroidism, biliary cirrhosis ↓ in Malnutrition, hyperthyroidism, colorectal CA Management, ↑ cholesterol Diet–↓ saturated fats, weight loss, regular exercise, medications. See Bad cholesterol, Fish, Good cholesterol, HDL, Hypercholesterolemia, LDL, RLP, VLDL.

---

Patient discussion about Understanding Cholesterol.

Q. How can I increase my HDL cholesterol levels? My Doctor told me that my cholesterol levels are not good and that I should lower my LDL and higher my HDL. I understand how to lower the cholesterol, but how can I increase the HDL?

A. Here are a few things you can do in order to raise your HDL levels:
Aerobic exercise
Lose weight
Stop smoking
Cut out the trans fatty acids from your diet.
Alcohol: one or two drinks per day can significantly increase HDL levels
Increase the monounsaturated fats in your diet.
Add soluble fiber to your diet.

Q. Can omega-3 make my cholesterol lower? My doctor told me that I have too much cholesterol in my blood, and that it can cause heart attack or stroke, but if I keep it low than my risk will be lower. He told me that because it’s not that high level I can try to change my diet before I have to start taking medication. I heard that omega-3 can make my cholesterol level low. Is that true? Do I have to take it in pills? Is it safe?

A. You can consume omega-3 either as pills or in fish oil, fatty fish (such as salmon) and vegetarian food such as flaxseed and flaxseed oil, canola oil, soybean oil, and nuts.

Q. What is a cholecystectomy and how is it done? My Doctor diagnosed me with gallstones and said I have to have a cholecystectomy surgery. What is this and how is it done?

A. Cholecystectomy is a surgery in which the gallbladder is removed. Don't be alarmed since you can live without your gallbladder. When the gallbladder is gone, bile flows directly from the liver into the small intestine.
You will probably have a laparoscopic cholecystectomy, which means a surgeon will make a small slit in your abdomen, then insert a tubelike instrument which has a camera and surgical instruments attached. This is used to take out the gallbladder with the stones inside it.
This procedure causes less pain than open surgery, is less likely to cause complications, and has a faster recovery time. This surgery is performed in an operating room and you will be under general anesthesia. It usually takes 20 minutes to one hour.