Optional on nutrition label unless added as a nutrient supplement. Helps regulate the use of carbohyrate, fat and protein for energy production. Acid- soluble in water, stable to oxidizing and reducing agents, and labile to dry heat, hot alkali or hot acid. Essential for all living organisms including man, to maintain normal skin, normal growth, and normal development of the central nervous system. Food sources are yeast, meats, egg yolks, dairy products, and green leafy vegetables.