Types of fat and the role of cholesterol
Types of fatThere are two main types of fats found in food: saturated and unsaturated fats.
Saturated fatFats that are saturated tend to be solid at room temperature and can be found in greater amounts in whole milk, cream, butter, hard cheese, meats, coconut oil, and palm oil. Saturated fats increase the risk of cardiovascular disease by raising the “bad” cholesterol in your blood. Fatty processed meats, baked cereal-based foods such as cakes, pastries and biscuits, and whole milk products are sources of saturated fats in the Australian diet.
Unsaturated fatFats that are unsaturated tend to be liquid at room temperature, such as those found in vegetable oil and soft margarines. Unsaturated fats consist of both monounsaturated fats and polyunsaturated fats.
What is monounsaturated fat?Monounsaturated fats are the most common fats found in plant-based oils such as olive, canola and peanut oils, in monounsaturated soft margarines, avocados and nuts. Unlike saturated fats, monounsaturated fats help lower cholesterol levels in your blood. It is advised that people replace saturated and trans fats in their diet with monounsaturated or polyunsaturated fats which help to lower blood cholesterol levels. This can be achieved by eating less high fat foods and more fresh fruit and vegetables.
What is polyunsaturated fat?Polyunsaturated fats are essential for your health. There are two types of polyunsaturated fat: omega-6 and omega-3. Omega-6 type fats are found in vegetable oils such as canola and sunflower and are essential for growth, cell structure, and maintaining a healthy immune system. Omega-3 type fats are found in oils from cold water fish such as salmon, tuna and sardines and in grass-fed Australian beef. Other types are also found in flax seeds (linseed oil). Omega-6 fats help to lower the risk of cardiovascular disease. Omega-3 fats have a role in regulating blood pressure and blood clotting, in helping to maintain a healthy immune system, and assists in brain and spinal cord function.
Replacing saturated fat in your diet with monounsaturated and polyunsaturated fat can help reduce your risk of cardiovascular disease.
What is trans fat?Trans fat is a type of unsaturated fat that because of its structure acts like saturated fat, causing your blood cholesterol levels to rise. Trans fats occur naturally in small amounts in meat and some dairy products, but are mainly found in manufactured processed foods such as cakes, biscuits, pies, and some fatty take-aways. Food containing trans fat should be avoided as much as possible.
It is advised that people replace saturated and trans fats in their diet with monounsaturated or polyunsaturated fats, which help lower blood cholesterol levels. This can be achieved by eating less high fat foods and more fresh fruit and vegetables. However, even the healthier fats need to be enjoyed in moderation.
The role of cholesterolCholesterol is a fat-like substance that has a number of important functions in the body. It is required for the production of some hormones, such as the sex hormones oestrogen and testosterone, and occurs in very high concentrations in the brain and nervous system. Cholesterol also helps to assist with the absorption of fat from food. Too much cholesterol in our blood however, can damage our arteries and lead to heart disease.
Most of our body’s cholesterol needs are met through the cholesterol that is made in our liver from saturated fats; the remainder of the cholesterol comes from some of the foods we eat. Cholesterol containing foods are animal-based foods, not plant foods. Foods high in cholesterol include offal meats like liver and kidney, egg yolk, and some seafoods such as prawns.
Although it is important to limit the amount of cholesterol containing foods that you eat, for most people dietary cholesterol doesn’t have a major impact on blood cholesterol levels. Studies have found that diets high in saturated fat have a greater impact on a person’s blood cholesterol levels and associated health risks, than the intake of dietary cholesterol alone. However high cholesterol intake is not generally encouraged.Diets high in saturated fat – butter, cream, fast food, chocolate etc – will elevate your cholesterol level and thereby increase your risk of cardiovascular disease.