"What they do Although water-soluble vitamins have many tasks in the body, one of the most important is helping to free the energy found in the food you eat. Others help keep tissues healthy. Here are some examples of how different vitamins help you maintain health: Release energy. Several B vitamins are key components of certain coenzymes (molecules that aid enzymes) that help release energy from food. Produce energy. Thiamin, riboflavin, niacin, pantothenic acid, and biotin engage in energy production. Build proteins and cells. Vitamins B6, B12, and folic acid metabolize amino acids (the building blocks of proteins) and help cells multiply. Make collagen. One of many roles played by vitamin C is to help make collagen, which knits together wounds, supports blood vessel walls, and forms a base for teeth and bones. Words to the wise Contrary to popular belief, some water-soluble vitamins can stay in the body for long periods of time. You probably have several years’ supply of vitamin B12 in your liver. And even folic acid and vitamin C stores can last more than a couple of days. Generally, though, water-soluble vitamins should be replenished every few days. Just be aware that there is a small risk that consuming large amounts of some of these micronutrients through supplements may be quite harmful. For example, very high doses of B6—many times the recommended amount of 1.3 milligrams (mg) per day for adults—can damage nerves, causing numbness and muscle weakness. A closer look at fat-soluble vitamins Rather than slipping easily into the bloodstream like most water-soluble vitamins, fat-soluble vitamins gain entry to the blood via lymph channels in the intestinal wall (see illustration). Many fat-soluble vitamins travel through the body only under escort by proteins that act as carriers."