The Water-Soluble Vitamins and Choline

• Most water-soluble vitamins are more readily excreted from the body than are fat-soluble vitamins

• Since any excess generally ends up in the urine or stool and very little is stored, consuming good sources of the water-soluble vitamins regularly is important

• Because they dissolve in water, large amounts of these vitamins can be lost during food processing and preparation

• Light cooking methods, such as stir-frying, steaming and microwaving, best preserve vitamin content

• B Vitamins are thiamin, riboflavin, niacin, pantothenic acid biotin, vitamin B-6, folate, and vitamin B-12

• B vitamins function as coenzymes, small molecules that interact with enzymes to enable enzymes to function

• In essence, the coenzymes contribute to enzyme activity

• As coenzymes, B vitamins play many key roles in metabolism

• The metabolic pathways used by carbohydrates, fats, and amino acids all require input from B vitamins

• After being ingested, the B vitamins are first broken down from their coenzyme forms into free vitamins in the stomach and small intestine

• The vitamins are then absorbed, primarily in the small intestine

• Once inside cells, the coenzyme forms are resynthesized

• Although some vitamins are sold in the coenzyme forms in health-food stores, there is no need to consume the coenzyme forms themselves

• These are broken down during digestion and we make them when needed

Category: Biochemistry Notes