High phosphorus intake only slightly affects serum minerals, urinary pyridinium crosslinks and renal function in young women

Abstract

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 20–30 y.

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 β-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.

European Journal of Clinical Nutrition (2001) 55, 153–161