There are two main types of cholesterol in the body which are known as LDL and HDL cholesterol. LDL stands for low density lipoprotein and is commonly referred to as ‘bad cholesterol’. HDL stands for high density lipoprotein and is commonly referred to as ‘good cholesterol’. Both LDL and HDL cholesterol enable transport of different fat molecules around the body. LDL particles however, can transport cholesterol into artery walls, where it can build up to form plaques, resulting in heart disease. HDL’s role is to remove this build up from arteries. It is therefore preferable to have lower levels of LDL cholesterol and higher levels of HDL cholesterol to protect against heart disease.
Cholesterol in the diet is obtained from animal foods such as meat, dairy and eggs. All plant foods are cholesterol free. Contrary to popular belief, cholesterol from foods causes only a small increase in total cholesterol and LDL cholesterol, substantially less than saturated fat and trans fat intake. In fact, the majority of people don’t respond to dietary cholesterol.
Approximately 25% of the population have been dubbed ‘hyper-responders’ because their blood levels do increase with dietary cholesterol. It is important to note however, that dietary cholesterol has been shown to increase HDL cholesterol (the good cholesterol) which is important for heart health. Dietary cholesterol has also been shown to increase the size of both LDL and HDL particles making LDL cholesterol less likely to build up in arteries and cause heart disease and making HDL particles more effective at removing cholesterol from the arteries.
In the past, it was thought eating foods containing cholesterol would increase the concentration of cholesterol in the blood. High blood cholesterol is linked to an increased risk of heart disease. Cholesterol is only found in animal products, and this led to people altering the types of food they consumed.
Recent research has shown that it is in fact the saturated fat in our food that affects cholesterol, increasing both total and LDL (‘bad’) levels. Studies have shown eating up to six eggs a week provides some nutritional benefits without increasing the risk of heart disease. The New Zealand Heart Foundation recommends that people at high risk of heart disease limit their intake of eggs to three per week as part of a diet low in saturated fat.
More information about cholesterol and eggs.