When most people hear the word “cholesterol” they think of health problems like blocked arteries, heart attacks and strokes, but cholesterol is actually an essential chemical in the human body and has many vital functions. We don’t need to eat cholesterol though, because our bodies make all the cholesterol that we need. If we do eat foods containing cholesterol our bodies normally compensate by making fewer cholesterol molecules.
If a blood test shows that you have a high level of cholesterol in your blood this may not indicate a problem. It depends on what type of cholesterol predominates in the blood. All cholesterol molecules are the same, but they are carried in the blood by different types of lipoprotein molecules.
Low density lipoproteins attached to cholesterol form LDL cholesterol. Low density lipoproteins carry cholesterol from the liver, where it’s made, to the cells, which need it. However, if there is too much cholesterol to be transported, there will be too much LDL cholesterol. The cholesterol may be deposited in artery walls, where it forms part of a deposit called plaque. Plaque production can lead to blocked arteries. Interestingly, researchers have found that for most people eating food containing cholesterol doesn’t make the blood level of LDL cholesterol rise. Eating a lot of saturated fat or trans fats does, however.
On the other hand, high density lipoproteins pick up cholesterol from the arteries and take it to the liver to be processed. The liver converts cholesterol to other substances or excretes it into the small intestine. The combination of high density lipoproteins and cholesterol is known as HDL cholesterol. It’s considered desirable to have a high level of HDL cholesterol (known as the “good” cholesterol) in the blood and a low level of LDL cholesterol (the "bad" cholesterol). Two techniques to increase the level of HDL cholesterol in the body include getting regular exercise and losing weight if necessary.
To increase the ratio of HDL cholesterol to LDL cholesterol we should avoid smoking, since smoking lowers HDL cholesterol. We should also change the types of fats that we eat. Saturated fat should be limited and trans fats avoided. Trans fats have been found to lower HDL cholesterol. Instead, we should eat foods containing monounsaturated fats (such as olive oil and almonds) which lower LDL cholesterol. Eating soluble fiber also lowers LDL cholesterol. Foods containing soluble fiber include oatmeal, barley, and a range of fruits and vegetables.