Total body phosphorus content is 11 to 14 g/kg lean body mass, which accounts for ~1% of total body mass. The normal range of serum phosphate levels is 0.9 to 1.6 mmol/L (2.8-5 mg/dL). The daily dietary phosphate intake is 19.4 to 29.0 mmol (600-900 mg) and depends on the quantity of dietary protein.
Gastrointestinal absorption of phosphate is increased by 1,25(OH)2D3 and parathyroid hormone (PTH)—mediated by 1,25(OH)2D3—and decreased by high quantities of dietary calcium and magnesium and by intake of substances that bind inorganic phosphate. A total of 90% to 95% of phosphate filtrated in the glomeruli undergoes reabsorption in the renal tubules. Urinary excretion of phosphate is increased by PTH, phosphatonins, nonrespiratory acidosis, and glucocorticoids, and decreased by PTH deficiency and physiologic concentrations of 1,25(OH)2D3.
Phosphorus-rich foods include fresh and canned fish, milk, cheese, cold meats, offal (brain, liver, kidney), dry fruit, chicken eggs, porridge, cereal, and bran.