Mono- and polyphosphates have similar effects on calcium and phosphorus metabolism in healthy young women.

PURPOSE

Phosphate (Pi) salts, often mono- (MP) or polyphosphates (PP), are commonly used as additives in the food industry. Previous studies have shown that the effects of MP and PP on calcium (Ca) and phosphorus (P) metabolism may differ. The aim of this study was to determine whether the effects of MP and PP salts differ on markers of Ca and P metabolism in young women.

METHODS

Fourteen healthy women 19-31 years of age were randomized into three controlled 24-h study sessions, each subject serving as her own control. During each session, the subjects received three doses of MP, PP or a placebo with meals in randomized order. Both Pi salts provided 1,500 mg P/d, and the diet during each session was identical. Markers of Ca and P metabolism were followed six times over 24 h.

RESULTS

During both MP and PP sessions, we found an increase in serum phosphate (S-Pi, p = 0.0001), urinary phosphate (U-Pi, p = 0.0001) and serum parathyroid hormone (S-PTH, p = 0.048 MP, p = 0.012 PP) relative to the control session. PP decreased U-Ca more than did MP (p = 0.014).

CONCLUSIONS

The results suggest that PP binds Ca in the intestine more than does MP. Based on the S-Pi, U-Pi and S-PTH results, both Pi salts are absorbed with equal efficiency. In the long run, increased S-PTH, caused by either an MP or PP salt, could have negative effects on bone metabolism.