Although elevated cholesterol levels can lead to health problems, in particular those related to the heart, both cholesterol and triglycerides - another type of lipid - have essential physiological roles to play in maintaining a healthy body.
Cholesterol is an essential component of cell membranes, which are the structures that border every cell in the human body.1 Without cholesterol, T-cells (a type of white blood cell), for example, would not maintain their cell membranes, leading to rupturing of the cells.
Cholesterol is also needed for the manufacture of steroid-based hormones, particularly sex hormones like testosterone and progesterone2. Other hormones, produced mainly by the adrenal gland, also require cholesterol for production. Aldosterone (the hormone that makes the kidneys retain water) and cortisol (the hormone that is important in suppressing inflammation in the body) are two such examples. Cholesterol must also be present for the skin to manufacture vitamin D, which plays a role in how the body handles calcium and assists in maintaining bone density.3
Cholesterol also enables the body to form bile acids, which are needed to help breakdown fats in the digestive tract so that they can be absorbed into the body.4 In addition, triglycerides are an important source of energy for the body, particularly when glucose is deficient.5