Answer:
Cholesterol plays important role in cell membrane and synthesizing essential molecules such as fat-soluble vitamins (vitamin D), hormones and bile acids to help us digest our food.
Cholesterol helped to regulate fluidity of membrane over the range of physiological temperatures. Generally, liver makes whole the cholesterol which is needed by our body. But from food (such as eggs, milk and meat) also cholesterol enters to the body.
In our body cholesterol is involves in the synthesis of vitamin D (is important for the growth of cells) and hormones, low level of these affects the health of the brain. If brain cells are not healthy, it leads to depression and anxiety.