Objective: Assessment of the physiological effects of a diet rich in phosphorus in young women.
Design: Control period I--commercial basic diet containing 1700 mg P and 1500 mg Ca/day for 4 weeks. Supplementation period--a 6 week high-phosphorus period of 3008 mg P and 1995 mg Ca/day. Control period II--4 weeks washout with basic diet as in period I.
Setting: Institute of Nutritional Science, Friedrich Schiller University, Jena.
Subjects: Ten healthy women, aged 20-30y.
Interventions: Orange juice and tablets, containing supplements of Ca5(PO4)3OH and NaH2PO4, totalling 1436 mg elemental phosphorus per day.
Results: There was an increase of 10.7+/-13.7 pg/ml in serum PTH, a decrease of 0.6+/-0.6 ng/ml in serum osteocalcin, an increase of 73.6+/-136.6 nmol/mmol creatinine in urinary pyridinoline and of 19.3+/-36.0 nmol/ mmol creatinine in urinary deoxypyridinoline, and a decrease of 2.6+/-9.3 mg/l in urinary microalbumin. All changes were insignificant. There were no changes in serum levels of Ca, PO4 or Zn, in serum concentration of 1,25-(OH)2D3, and in urinary beta-2-microglobulin excretion. Phosphorus supplementation caused intestinal distress, soft stools or mild diarrhoea.
Conclusions: In spite of a high phosphorus supplementation no significant changes in bone-related hormones, pyridinium crosslinks as markers of bone resorption and parameters of renal function in young women were found.