Minerals are needed by the body as structural components and regulators of various biological processes. The bioavailability of minerals depends on many factors. Minerals function in a variety of ways in the body. The concentration of these electrolytes must be maintained within certain ranges for cells to function properly. Calcium is important in the maintenance of bones and teeth, where it is primarily found with phosphorous as solid mineral crystals. The major minerals are sodium and chloride, potassium, calcium, phosphorus, magnesium, and sulfur. The major trace minerals are iron, zinc, selenium, iodine, chromium, copper and fluoride. The body needs more water each day than any other nutrient. Water plays an active role in many processes, including hundreds of chemical reactions. In addition, water provides protection, helps remove waste products, and serves as an important solvent and lubricant. Water is an important vehicle for transporting substances throughout the body and for removing waste products from the body.