Cholesterol is a type of fat found in your blood. If you have a raised cholesterol level, it tends to collect in the walls of blood vessels. If this occurs in the arteies that take blood to your heart, it can cause angina or a heart attack. Raised blood levels have been linked to high-fat diets, so reducing the total amount of fat that you eat is very important. However, the three different kinds of fats affect your blood levels in different ways. The major differences in fats are whether they are mainly saturated or unsaturated. The difference lies in their chemical structure.
The more hydrogen atoms present in the fat the more saturated the fat (and more generally the more solid at room temperature).
These are solid at room temperature- are found mostly in foods of animal origin such as meat and dairy produce. These fats are also found in large amounts in processed foods such as pies, pastries and biscuits. Most plant oils have quite a small amount of saturated fat.Some foods, such as eggs and offal, are rich in dietary cholesterol. However the intake of cholesterol in the diet has a smaller effect on blood cholesteral than foods high in saturated fats. So it’s more important to limit foods rich in saturated fat than to cut down on foods rich in dietry cholesterol.
These are liquid at room temperature and are divided into two sub groups:
Monounsaturates: the typical Mediterranean” diet is rich in these fats. The best sources are from olives, avocadoes, nuts and some oils, such as olive oil.
Polyunsaturates: are found in their most concentrated form in vegetable oils and nuts; fish is also a good source. These fats are essential for good health.
Some unsaturated fats are altered in a process known as hydrogenation this is when hydrogen atoms are added to the fat to make it more solid, for example when margarine is made from oil. As a result, it becomes more like saturated fat in the way that it behaves in our bodies. Some people think that these fats could be as damaging to our health as saturated fats. Unlike saturates, the amount of hydrogenated fats does not have to be declared on nutrition labels.
Fats That Are Beneficial To Our Health
There are certain fats that we actually need to eat for good health. This group of fats are known as essential fatty acids (EFAs). They are called essential because they are the only fats that our bodies cannot make and we should therefore include them in our diets. Research has found that EFAs may help prevent blood clots which can lead to heart attack or stroke. Some international studies have shown that diets high in one type of EFA, called omega-3, may also play a protective role in relation to some cancers-although evidence is, as yet, inconclusive. To ensure that youre getting an adequate supply of omega-3 fatty acid, experts recommend eating between one and three portions of oil rich fish every week, such as fresh tuna, herring, mackerel, sardines, lake trout, anchovies and salmon. Other good sources are walnut oil, rapeseed oil, soya oil and walnuts.