Dietary fat quality and circulating cholesterol levels in humans: a review of actions and mechanisms.

Consumption of saturated fats contributes to elevated circulating cholesterol levels, whilst either polyunsaturated or monounsaturated fats are linked to depressed levels. Since elevated serum cholesterol is a risk factor for coronary heart disease, it is of interest to understand the factors responsible for the responses elicited by dietary fat quality. Changes in faecal sterol excretion, exogenous cholesterol absorption, lipoprotein composition, and lipoprotein catabolism can coincide with changes in fat intake but may not necessary cause them. Whether or not rates of whole-body cholesterol synthesis respond to dietary fat quality is not known. To date, animal studies suggest that shifts in LDL receptor-mediated cholesterol transport are to blame for responses of circulating cholesterol levels to dietary fat.