Cholesterol is a form of fat (lipid) present in animal-derived foods. In humans it may be formed in the body or obtained from food. It is moved around the body in blood where it is bound to proteins.

Cholesterol in blood must be distinguished from cholesterol in food. There is no definite cut-off point below which no coronary heart disease occurs, but it is extremely uncommon below a blood cholesterol concentration of 4.5 millimole per litre. In Australia, it is recommended that total cholesterol in blood be below 5.5, in the USA below 5.2 and in Japan below 5.0 millimole per litre. Sometimes if the blood cholesterol level is above 5.5, it is because of an increase in 'HDL' or high density lipoprotein cholesterol, which is usually a good thing. Most of the blood cholesterol is 'LDL' or low density cholesterol, too much of which tends to deposit in tissues like the arteries.

Food factors which can increase the level of cholesterol in blood (or plasma or serum) include:

Food factors which can decrease the level of cholesterol in blood (or plasma or serum) include:

Some foods can protect against coronary heart disease other than through their effect on blood cholesterol. For example:

(a) reduces the stickiness of blood due to cells known as platelets, allowing it to flow freely,
(b) reduces blood pressure,
(c) decreases likelihood of heart to develop abnormal rhythms;