Yeh J K, Aloia J F, Semla H M, Chen S Y
J Nutr. 1986 Feb;116(2):273-80. doi: 10.1093/jn/116.2.273.
Mineral metabolism was studied by the metabolic balance technique in rats with and without administration of caffeine. Caffeine was injected subcutaneously each day at either 2.5 mg or 10 mg/100 g body weight for 2 wk before the balance studies. Urinary volume excretion was higher in the group given caffeine than in the control group, but the creatinine clearance was not different. Urinary excretion of potassium, sodium, inorganic phosphate, magnesium and calcium, but not of zinc and copper, was also higher in the rats given caffeine. The rank order of the difference was the same as the percent of ingested mineral excreted in urine in the absence of caffeine. Caffeine caused a negative balance of potassium, sodium and inorganic phosphate. There was no significant difference from the control levels and in the apparent metabolic balance of calcium and magnesium. The urinary and fecal excretion of zinc and copper were found to be unaffected by caffeine. It is suggested that chronic administration of caffeine may lead to a tendency toward deficiency of those minerals that are excreted primarily in urine.
采用代谢平衡技术，对给予和未给予咖啡因的大鼠的矿物质代谢进行了研究。在平衡研究前2周，每天以2.5毫克或10毫克/100克体重的剂量皮下注射咖啡因。给予咖啡因组的尿量排泄高于对照组，但肌酐清除率无差异。给予咖啡因的大鼠尿中钾、钠、无机磷酸盐、镁和钙的排泄量也较高，但锌和铜的排泄量没有变化。差异的排序与未给予咖啡因时尿中排泄的摄入矿物质百分比相同。咖啡因导致钾、钠和无机磷酸盐出现负平衡。钙和镁的表观代谢平衡与对照水平无显著差异。发现锌和铜的尿排泄和粪排泄不受咖啡因影响。提示长期给予咖啡因可能导致主要经尿液排泄的那些矿物质出现缺乏倾向。
