Do you associate "obesity" with "cholesterol"? Cholesterol is an indispensable compound in the human body. It is a necessary ingredient in the production of various hormones, cell membranes and bile acid, which is needed to digest food fat. Cholesterol is a fatty lipid excreted into the blood by the liver, and at elevated levels may build up along the blood vessels walls forming plaques and constricting the flow of blood to and from the heart, and the condition known as atherosclerosis. Two lipoproteins that attach to cholesterol have been shown to control the concentration of cholesterol in the blood. HD Lipoprotein (HDL) attaches to cholesterol to form HDL cholesterol, known as "good cholesterol" which transports the attached cholesterol out of the blood steam. LD Lipoprotein carries cholesterol into the blood stream as LDL cholesterol or "bad cholesterol", which is thought to promote the formation of blood vessel plaques.

LDL cholesterol becomes particularly  harmful once it has become oxidized. Oxidized low-density lipoprotein (ox-LDL) is the principal lipoprotein found in atherosclerotic lesions. The powerful anti-oxidative action of tea catechins can prevent this from happening. Tea catechins therefore function in two ways. They make it difficult to absorb LDL cholesterol into the blood stream, and also protect LDL cholesterol from oxidation.