Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Vitamins, one of the six nutrients considered to be vital to life, have a wide variety of biochemical functions such as regulating the mineral metabolism, cell and tissue growth and acting as antioxidants and, as they cannot be synthesized in sufficient quantities by the organism, must be taken in with diet. Learn more about vitamin B, a group of compounds that play an important role in cell metabolism, enhance the function of immune and nervous systems and maintain healthy skin, hair and muscle tone in the following pages.