Cholesterol is a conditionally essential nutrient, which is needed for brain health, cell membranes, and making steroid hormones such as Vitamin D, estrogen, testosterone, cortisol, aldosterone, and progesterone. It is also important for intra-cellular signaling between neurons.
Dietary sources of cholesterol are only from animals. Vegans are at increased risk of deficiency.
It is possible for cholesterol to be too high, leading to cardiovascular complications, or too low. The exact healthy range is controversial, and may be tied to a patient's APO-E genetics.