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 Ð commercial basic diet containing 1700 mg P and 1500 mg Caaday for 4 weeks. Supplementation period Ð a 6 week high-phosphorus period of 3008 mg P and 1995 mg Caaday. Control period II Ð 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 Ca 5 (PO 4 ) 3 OH and NaH 2 PO 4 , totalling 1436 mg elemental phosphorus per day. Results: There was an increase of 10.7 AE 13.7 pgaml in serum PTH, a decrease of 0.6AE 0.6 ngaml in serum osteocalcin, an increase of 73.6 AE 136.6 nmolammol creatinine in urinary pyridinoline and of 19.3 AE 36.0 nmola mmol creatinine in urinary deoxypyridinoline, and a decrease of 2.6 AE 9.3 mgal in urinary microalbumin. All changes were insigni®cant. There were no changes in serum levels of Ca, PO 4 or Zn, in serum concentration of 1,25-(OH) 2 D 3 , and in urinary b-2-microglobulin excretion. Phosphorus supplementation caused intestinal distress, soft stools or mild diarrhoea. Conclusions: In spite of a high phosphorus supplementation no signi®cant changes in bone-related hormones, pyridinium crosslinks as markers of bone resorption and parameters of renal function in young women were found.

Nutritional aspects of the prevention and treatment of osteoporosis

“…Moreover, similarly elevated PTH levels have been reported in diets that were low in calcium without being high in phosphorus (47). A controlled trial in young women found no adverse effects of a phosphorus-rich diet (3,000 mg/day) on bone-related hormones and biochemical markers of bone resorption when dietary calcium intakes were maintained at almost 2,000 mg/ day (48). At present, there is no convincing evidence that the dietary phosphorus levels experienced in the U.S. adversely affect bone mineral density.…”

The Impact of Protein Intake on Renal Function Decline in Women with Normal Renal Function or Mild Renal Insufficiency

“…This relation is important because a highphosphorus diet has been shown to cause nephrocalcinosis, tubular damage, and interstitial fibrosis in dogs (34). However, studies in humans addressing this concern are limited, and those that have been performed have yielded conflicting results (35,36). Nonetheless, because of these concerns, we included dietary phosphorus intake in all models to assess the independent effects of protein.…”

Understanding Sources of Dietary Phosphorus in the Treatment of Patients with Chronic Kidney Disease

“…Frequent or sustained elevations of PTH levels can have adverse effects on bone mineral content and architecture, although the significance of such borderline or temporary hyperparathyroidism without kidney dysfunction is unclear (24). A controlled trial of young women found no adverse effects of a P-rich diet of up to 3000 mg/d on bone-related hormones and biochemical markers of bone reabsorption as long as dietary calcium intakes were maintained at almost 2000 mg/d (25). At present, there is no convincing evidence that the usual P intake in the United States adversely affects bone mineral density in individuals without CKD; however, a recent study that used a food frequency questionnaire showed that higher dietary P intake or P-toprotein ratio was associated with increased 5-year death risk in 224 prevalent hemodialysis patients (26).…”