INTERACTION BETWEEN DIETARY PHOSPHATE AND CARBOHYDRATE ON GLUCOSE AND PHOSPHATE METABOLISMS IN HEALTHY YOUNG MEN.

Abstract

Interaction between the nutrients should be considered to understand the relationship between nutrient intake and disease. Here, we investigated the effects of combination of dietary phosphate and carbohydrate (glycemic index; GI) on urinary phosphate excretion, serum glucose, insulin, phosphate, PTH levels after the digestion of experimental meal in 11 young healthy men. We employed 4 different meals; high GI and high phosphate (HGHP), high GI and low phosphate (HGLP), low GI and high phosphate (LGHP), and low GI and low phosphate (LGLP). Barley was used for staple food in low GI meals, inversely white rice in high GI meals. Low phosphate meals contained 400 mg of phosphate, high phosphate meals contained 1200 mg of phosphate added as sodium phosphate. This study was performed as a crossover study, and approved by the ethical committee of the University of Tokushima. Ingestion of HGHP meal revealed higher postprandial phosphate excretion than LGHP meal. This difference was not observed between HGLP and LGLP meals. HGHP meals was also involved in higher postprandial increases in blood glucose and insulin than HGLP. Meanwhile intact PTH level in the ingestion of LGHP meals was significantly higher than that in HGHP. No significant difference in serum phosphate level between HGHP and LGHP groups. These data indicate that interaction between dietary phosphate and carbohydrate affected postprandial changes in serum glucose and phosphate handling in healthy young men.