Plays an important role in the body's utilization of carbohydrates and fats and in the synthesis of protein for the growth, maintenance, and repair of cells and tissues. It is also crucial for the production of ATP, a molecule the body uses to store energy. Phosphorus is a mineral that makes up 1% of the total body weight. It is present in every cell of the body, but 85% of the body's phosphorus is found in the bones and teeth. Phosphorus works with the B vitamins. It also assists in the contraction of muscles, in the functioning of kidneys, in maintaining the regularity of the heartbeat, and in nerve conduction. The main food sources are the protein food groups of meat and milk. A meal plan that provides adequate amounts of calcium and protein also provides an adequate amount of phosphorus. Although whole-grain breads and cereals contain more phosphorus than cereals and breads made from refined flour, this is a storage form of phosphorus called phytin, which is not absorbed by humans. Fruits and vegetables contain only small amounts of phosphorus.