Clinical Nutrition in Gastrointestinal Disease

Alan Buchman, MD, MSPH

Chapter 3: Micronutrient Deficiencies (continued)

Clifford Lo, MD, MPH, ScD

Vitamins are a diverse group of chemical substances that may function as coenzymes or prohormones. They are essential for human life in small quantities (as opposed to macronutrients, which are primarily used for energy) and cannot be synthesized by humans, so they must be provided in the diet. The term “vitamin” was coined by Casimir Funk from “vita-,” or “life,” and “amine,” because they were initially mistakenly assumed to be amines. Later, McCollum separated extracts of the growth factors into fat soluble A and water soluble B, which…