cholesteol

Cholesterol, often misspelled as cholesteol, is a lipid molecule essential to many biological processes. It is a sterol found in animal tissues and is not produced by plants. In humans, most cholesterol is synthesized in the liver, with smaller amounts absorbed from animal-based foods. Plasma cholesterol travels in lipoprotein particles, including low-density lipoprotein (LDL), high-density lipoprotein (HDL), very-low-density lipoprotein (VLDL), and chylomicrons.

Cholesterol is a structural component of cell membranes, modulating fluidity and microdomain organization. It is also a precursor for steroid hormones (such as cortisol and sex hormones), bile acids, and vitamin D.

Endogenous synthesis is regulated by HMG-CoA reductase; statin medications inhibit this enzyme. Clinically, cholesterol is measured as total cholesterol and as lipoprotein fractions: LDL-C and HDL-C. High LDL-C is a major risk factor for atherosclerotic cardiovascular disease; HDL-C is considered protective. Target values depend on overall risk profile.

Dietary cholesterol impacts blood levels variably; saturated fats and trans fats tend to raise LDL-C, while plant sterols can reduce absorption. Management of high cholesterol typically combines lifestyle changes (healthy diet, regular exercise, weight control) with, if needed, medications such as statins, ezetimibe, or PCSK9 inhibitors.