Cholesterol

general

A waxy substance found in animal-based foods and produced by the liver.

Definition

A waxy substance found in animal-based foods and produced by the liver. Needed for cell membranes and hormones. Dietary cholesterol has less impact on blood levels than previously believed. DV is 300mg/day.

What Is Cholesterol?

Cholesterol is a waxy, fat-like sterol found in every cell of the body. It is essential for producing cell membranes, bile acids needed for fat digestion, steroid hormones (including estrogen, testosterone, and cortisol), and vitamin D. The liver synthesizes approximately 75–80% of the body's cholesterol; the remaining 20–25% comes from dietary sources such as meat, poultry, eggs, and dairy products.

Because cholesterol is not water-soluble, it is transported in the bloodstream by lipoproteins — protein-lipid particles that carry fats through the aqueous environment of blood.

LDL, HDL, and Cardiovascular Risk

The two most clinically relevant lipoproteins are:

  • LDL (Low-Density Lipoprotein): Often called "bad" cholesterol, elevated LDL-C is a major risk factor for atherosclerosis. Optimal LDL-C is generally below 100 mg/dL; levels above 160 mg/dL are considered high.
  • HDL (High-Density Lipoprotein): Often called "good" cholesterol, HDL transports cholesterol back to the liver for excretion. Higher HDL-C (above 60 mg/dL) is associated with reduced cardiovascular risk.

Total cholesterol below 200 mg/dL is considered desirable; 200–239 mg/dL is borderline high; 240 mg/dL and above is high.

Diet and Cholesterol

Dietary cholesterol has a smaller effect on blood cholesterol than once thought. Saturated and trans fats are more potent drivers of elevated LDL-C. Current dietary guidelines have removed strict numeric limits on dietary cholesterol for most people. Soluble fiber (found in oats, legumes, and apples), plant sterols, and unsaturated fats from olive oil, nuts, and fatty fish are evidence-based dietary strategies for improving the cholesterol profile.