Cholesterol diet and cvd treatment

Cholesterol is transported in the blood as lipoproteins because it is insoluble and cannot dissolve in plasma.

High-density lipoproteins (HDLs) carry cholesterol from the tissues to the liver, where it is broken down, whereas low-density lipoproteins (LDLs) carry cholesterol from the liver to the tissues, and high levels of LDL can deposit cholesterol in the artery walls.

A favourable HDL:LDL ratio matters more than total cholesterol alone, and a high LDL level is causally linked to cardiovascular disease (CVD).

This causal link is supported by several types of evidence: epidemiological studies, the genetics of familial hypercholesterolaemia, animal experiments and intervention trials. Together these meet several of the Bradford-Hill criteria for establishing causation.

People can lower their risk of coronary heart disease through diet (eating less saturated fat and salt, and more unsaturated fats and fibre), taking regular exercise and not smoking.

Obesity is monitored using the body mass index, calculated as mass ÷ height², and the waist-to-hip ratio, with central abdominal fat being especially harmful.

When lifestyle changes alone are insufficient, four classes of drug are used to treat CVD: antihypertensives, statins, anticoagulants and platelet inhibitors.

Antihypertensives lower blood pressure, while statins reduce blood LDL levels by inhibiting the enzyme HMG-CoA reductase, which is needed for cholesterol synthesis in the liver. Anticoagulants prevent the formation of dangerous blood clots, and platelet inhibitors reduce platelet aggregation.

Each drug carries both benefits and side effects, so doctors must balance these against the patient's individual risk profile when deciding on treatment.