Phosphate

Phosphate is an electrolyte formed when the mineral phosphorus binds with oxygen. In the body it exists as ions and helps carry electrical charges within bodily fluids and tissues.

Physiological role

Phosphate occurs as three ionic species: dihydrogen phosphate (H2PO4^-), hydrogen phosphate (HPO4^2-) and phosphate (PO4^3-). About eighty-five percent of the body’s phosphate is bound in bones and teeth as calcium phosphate, while the remainder circulates in cells and extracellular fluid where it forms part of phospholipids, nucleotides and adenosine triphosphate (ATP). This electrolyte works alongside calcium to build bones and teeth and helps regulate muscle and nerve function. Phosphate also helps maintain acid-base balance by acting as a buffer. The kidneys, bones and intestines regulate phosphate levels tightly because both deficiency and excess can be harmful. Low phosphate can result from malnourishment or prolonged use of antacids and can weaken muscles and bones. High phosphate often relates to reduced kidney function or massive cell destruction, and excess phosphate circulating in the blood can disrupt calcium levels.

Food sources and practical notes

Foods provide ample phosphate. Animal foods such as meat, poultry, fish, milk, yogurt and cheese are rich sources. Nuts, seeds, legumes and whole grains are also good sources, although certain plant compounds can reduce absorption. Most adults need around 700 mg of phosphate per day, and typical diets exceed this amount. Sports drinks occasionally include phosphate salts such as sodium phosphate to maintain acidity and support energy systems, but the amounts used are small compared with everyday foods. People with kidney disease should monitor phosphate intake because impaired kidneys may have trouble removing excess.

A brief summary: phosphate is an important intracellular anion that stabilizes bone, fuels metabolic reactions and buffers acids. Because it is abundant in food and regulated by the kidneys, most athletes obtain sufficient phosphate without supplementation, though small amounts are used in sports drink formulas.

Related Terms: sodium chloride, sodium citrate, potassium chloride, magnesium citrate, calcium chloride