Dietary cholesterol is the cholesterol that arrives in food — inessential cholesterol which is not synthesized by the liver, but passes into the body from animal products such as egg yolk, offal, shellfish, and full-fat dairy. For decades it was treated as a direct driver of blood cholesterol and heart disease, and dietary guidelines capped it tightly. Modern nutrition has softened that view: for most people, blood cholesterol responds more to saturated and trans fats than to cholesterol eaten, because the liver simply makes less when more arrives in food — though a minority of “hyper-responders” are more sensitive. Current guidance therefore focuses on overall dietary patterns rather than a single number. The story of dietary cholesterol is a case study in nutrition science revising itself as the evidence on metabolism matured.