Cholesterol being a fat substance is not soluble in blood and hence it is carried by proteins. This combination of fats and proteins are called the lipoproteins. Lipoproteins are of varies types and have various functions in the body. These are further classified depending on their density as low density lipoprotein, high density lipoprotein, very-low density lipoprotein and intermediate density lipoprotein.
The low density lipoprotein or LDL is commonly known as the badcholesterol carries cholesterol to the arteries which causes deposition of cholesterol in the walls of the arteries and thus causes narrowing of the lumen within the arteries, this may also lead to clogging up of arteries with a plague ultimately resulting in a heart attack or stroke. Hence, high LDL levels are considered an important indicator of cardiovascular and cerebrovascular disease. Thickening of arteries and narrowing of their lumen may also cause diminished supply of blood to the limbs also known as peripheral vascular disease. LDL level of 100 mg/dl or below are considered optimal. Levels of 190mg/dl require treatment. Necessity of treatment is calculated based on a 10 year risk calculation.
The high density lipoprotein or HDL is also termed as the goodcholesterol .Unlike LDL, cholesterol carried by the HDL does not get deposited in the arterial walls. In fact, it may even reduce any additional cholesterol already present in the arterial wall, reducing the size of a plaque. HDL keeps the cholesterol in a dissolved state and moves it safely through the body. HDL carries the cholesterol to liver where it is broken down or removed from the body. Hence higher levels of HDL are desirable. HDL level of 60 mg/dl or above are considered optimal and protective against heart disease.
Lowering your LDL level and elevating HDL levels:
A diet low in saturated fats, low in cholesterol in which less than 7 per cent of calories are obtained from saturated fat and contains less than 200mg of dietary cholesterol per day is recommended. It may contain variety of nutritious foods including fruits, vegetables, whole grains, low-fat or no-fat dairy products, fish, poultry without the skin, and lean meats. It is recommended to consume only enough calories to equate the requirement and avoid weight gain. If LDL is not lowered enough by reducing saturated fat and cholesterol intake, the amount of soluble fibre in your diet has to be increased. Food products that contain naturally occurring substances found in some plants like cholesterol-lowering margarines can also be added.
If you are overweight, lowering your weight can help lower LDL and is especially important for those with other risk factors that like high triglyceride or low HDL levels or body mass index is greater than 30 kg/m2 or a waist measurement more than 40 inches for men or more than 35 inches for women.
Regular physical activity with a minimum duration of 3o minutes is recommended for everyone.
Lifestyle changes have to be inculcated and maintained even if treatment with drugs is started. Lifestyle modifications not only help in maintaining a lower dosage of drugs but also in reducing other risk factors. There are several types of cholesterol-lowering drugs available, including:
they reduce the levels of cholesterol by preventing its synthesis in the liver.
Bile acid sequestrants:
they decrease the amount of fat absorbed from food
Cholesterol absorption inhibitors:
they decrease the amount of cholesterol absorbed from food and lower triglycerides
it prevents loss of HDL from the liver and lowers triglycerides.
Omega-3 fatty acids:
they increase the level of HDL and lowers triglycerides in blood.