21/09/2022
Cholesterol A 27-carbon precursor of steroid hormones and bile acids which is an integral component of cell membranes and plasma lipoproteins; it is a precursor of bile acids and important in the synthesis of steroid hormones. It is the main component of the most common type of gallstones and is a major constituent of arterial atheromas; increased cholesterol is associated with ASHD, CAD, increased risk of death due to acute MIs and strokes.
Sources
Animal fat, bile, blood, brain, milk, egg yolk, myelin sheaths, liver, kidneys, adrenal gland.
Metabolism
Cholesterol is absorbed from ingested foods—diets high in saturated (animal) fats increase cholesterol levels—and synthesised in the liver. HDL-C is metabolised efficiently, and thus is “good” cholesterol; “bad cholesterol”, LDL-C, is inefficently metabolised; when the total cholesterol (TC) is increased (usually = 200 mg/dL), it is common practice to measure the levels of HDL-cholesterol and LDL-cholesterol.
Lab
TC is measured in routine chemistry panels; cholesterol is transported in the circulation by carrier proteins, which are classified according to their density (HDL, LDL, VLDL) based on density-gradient ultracentrifugation.
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
• TC = 5.17–6.18 mmol/L—US: 200–239 mg/dL;
Low risk
• TC < 5.17 mmol/L—US: 200 mg/dL;
• LDL-Cl < 130 mg/dL;
• HDL-C > 55 mg/dL.
Increased in
Hypercholesterolemia, nephrotic syndrome, hypothyroidism, biliary cirrhosis, high saturated fats in diet.
Decreased in
Malnutrition, hyperthyroidism, colorectal CA.
Management, hypercholesterolemia
Diet (decreased saturated fats), weight loss, regular exercise, medications. Medical Doctors