" Cholesterol is a little waxy lipid (fat) molecule that happens to be one of the most important substances in the human body. Every cell membrane has cholesterol as a critical structural and functional component. Brain cells need cholesterol to make synapses (connections) with other brain cells. Cholesterol is the precursor molecule for important hormones such as testosterone, estrogen, DHEA, cortisol, and pregnenolone. Cholesterol is needed for making the bile acids that allow us to digest and absorb fats. Cholesterol interacts with sunlight to convert into the all-important vitamin D. Bottom line is that you can’t live without cholesterol, "

― Mark Sisson , The Primal Blueprint: Reprogram Your Genes for Effortless Weight Loss, Vibrant Health, and Boundless Energy