Riboflavin (vitamin B2)

Riboflavin (vitamin B2), the second B vitamin to be identified, was once called “vitamin G.” Its present name is derivative of its chemical structure, a carbon-hydrogen-oxygen skeleton that includes ribitol (a sugar) attached to a flavonoid (a substance from plants containing a pigment called flavone). Like thiamin, riboflavin is a coenzyme. Without it, your body can’t digest and use proteins and carbohydrates. Like vitamin A, it protects the health of mucous membranes — the moist tissues that line the eyes, mouth, nose, throat, vagina, and rectum. You get riboflavin from foods of animal origin (meat, fish, poultry, eggs, and milk), whole or enriched grain products, brewer’s yeast, and dark green vegetables (like broccoli and spinach).