The importance of cholesterol levels and the effect on fitness and longevity is a comparatively recent health issue. Medical wisdom has it that certain types of cholesterol are good for us and other types are not. High levels of some cholesterols can contribute to heart disease and circulatory problems such as hypertension and strokes. Because of this many doctors believe that everyone should monitor their cholesterol levels.
Cholesterol risk factors
Cholesterol checks are even more important if a family history of heart disease or strokes exists, or before the age of 65 if related to existing heart problems. Men who are overweight or obese, who smoke, have diabetes or high blood pressure, have an increased risk of health problems.
The role of cholesterol in disease is not as straight forward as it may first appear. Research has shown that about half of all men suffering heart attacks do not have high cholesterol levels (there is a lot of work looking at the role of inflammation in heart disease). Moreover, some countries with typically high fat diets (e.g. France) also report high levels of cholesterol in the population, yet have low rates heart disease.
What is cholesterol?
Cholesterol is found naturally in the blood stream and body cells. Cholesterol, a soft waxy lipid (fat) that cannot be dissolved in the blood, is important for, amongst other things, cell membrane production and some hormone production. It comes from two sources:
1) We take in fats when we eat animal products such as meat, fish, poultry, eggs, butter, whole milk and cheese.
2) Our own bodies produce it. Some foods, although they do not contain animal fats may contain trans-fats that cause the body to produce cholesterol.
2 Main Types of Cholesterol
LDL the 'bad' cholesterol (Low density lipoprotein)
LDL cholesterol (Low density lipoprotein) is considered the 'bad' cholesterol. This is the type that can block arteries. Cholesterol builds up inside the blood vessel walls in the form of plaques (known as arteriosclerosis). The plaques can restrict blood flow to the heart and if they burst the contents spill out, clots can form and travel around the body in the blood stream. The clots can block the small blood vessels in the heart leading to a heart attack. If they block vessels in the brain they cause a stroke.
HDL the good cholesterol (high density lipoprotein)
HDL cholesterol is considered to be the 'good' cholesterol. Research suggests that this type protects the body and reduces the chances of a heart attack.