Phosphorus is a major mineral that partners with calcium to build and maintain strong bones and teeth. It is also a core part of ATP – the molecule your cells use for energy – and of the phospholipids that make up cell membranes, helping every cell in your body function and communicate properly. Because phosphorus is widespread in foods like meat, dairy, fish, nuts, seeds, and whole grains, most people meet their needs through diet. The main focus is usually on balance with other minerals, especially calcium, rather than aiming for very high supplemental intakes.