Cholesterol is present in the blood and in most of cells, and is a part of substances called lipids. In the blood, cholesterol is bound to certain proteins what makes lipoproteins. Roughly, they are two types of lipoproteins:

• LDL = Low Density Lipoproteins that contain a lot of cholesterol (what makes them low density). This is denoted as LDL cholesterol and is called “bad” cholesterol since, when in excess, it deposits on the inner arterial walls, building plaques called atheromas that harden and clog arteries. The disorder is known as atherosclerosis (from Greek atheroma = cholesterol plaque; sclerosis = hardening of arterial wall).
• HDL = High Density Lipoproteins that contain small amount of cholesterol denoted as HDL cholesterol that takes excessive cholesterol from LDL and carry it away from the blood, so it is called “good” cholesterol. 

Blood cholesterol is uptaken by cells that use it to build cell membranes, hormones, vitamin D and bile acids among other. It is good to have some cholesterol of both types in the blood.

High level of LDL cholesterol in the blood is a strong risk factor for atherosclerosis that is a major cause of stroke and heart attack. 

How to Lower High LDL Blood Levels?

By exercise and some restriction in diet.

Exercise

Exercising for at least 30 minutes a day every day helps to reduce LDL holesterol level in the blood. Any exercise that speed up your heart rate and is appropriate to your health status and age can be helpful.

Diet

 and related juices

Foods to avoid in high LDL:

• Red meat, especially pork, and other fatty meat
• Egg yolk
• Dairy like whole fat milk, cheese, butter, cream
• Products with trans fats like margarines and chips with “hydrogenated fats”
• Chocolate, cocoa

To try:

• Oatmeal
• Morning cereals
• Whole grains
• Whole meal or whole grain bread
• Salads
• Rice
• Potatoes
• Pasta
• Plant sterols and stanols (added in fortified foods like orange juice)
• Fruits like bananas and citruses
• Vegetables like salads, legumes

References:

1. How to lower cholesterol  (ehealthmd.com)