When you have too much LDL cholesterol in your body it can build up in your arteries, clogging them and making them less flexible. Hardening of the arteries is called atherosclerosis.
Lowered production of thyroid hormone (hypothyroidism) leads to an increase in total and LDL cholesterol. Excess thyroid hormone (hyperthyroidism) has the opposite effect.
High blood cholesterol on its own has also been implicated in the loss of memory and mental function. Having high blood cholesterol may accelerate the formation of beta-amyloid plaques, the sticky protein deposits that damage the brain in people with Alzheimer’s disease.
In the digestive system, cholesterol is essential for the production of bile — a substance that helps your body break down foods and absorb nutrients in your intestines. But if you have too much cholesterol in your bile, the excess forms into crystals and then hard stones in your gallbladder.