Background Despite epidemiologic evidence for increased cardiovascular morbidity and mortality associated with both high dietary and serum phosphate in humans with normal renal function, no controlled phosphate intervention studies of systemic hemodynamics have been reported. Higher serum 25(OH) vitamin D levels are associated with better cardiovascular outcomes, but vitamin D increases intestinal phosphate absorption.

Methods We conducted a prospective outpatient study with blinded assessment in 20 young adults with normal renal function randomized to high phosphate (regular diet plus 1 mmol/kg body wt per day of Na as neutral sodium phosphate) or low phosphate (regular diet plus lanthanum, 750 mg thrice/day, plus 0.7 mmol/kg body wt per day of Na as NaCl) for 11 weeks. After 6 weeks, all subjects received vitamin D₃ (600,000 U) by intramuscular injection. Outcome parameters were 24-hour ambulatory systolic and diastolic BP (SBP and DBP), pulse rate (PR), biomarkers, and measures of endothelial and arterial function.

Results Compared with the low-phosphate diet group, the high-phosphate diet group had a significant increase in mean±SEM fasting plasma phosphate concentration (0.23±0.11 mmol/L); 24-hour SBP and DBP (+4.1; 95% confidence interval [95% CI], 2.1 to 6.1; and +3.2; 95% CI, 1.2 to 5.2 mm Hg, respectively); mean 24-hour PR (+4.0; 95% CI, 2.0 to 6.0 beats/min); and urinary metanephrine and normetanephrine excretion (54; 95% CI, 50 to 70; and 122; 95% CI, 85 to 159 µg/24 hr, respectively). Vitamin D had no effect on any of these parameters. Neither high- nor low-phosphate diet nor vitamin D affected endothelial function or arterial elasticity.

Conclusions Increased phosphate intake (controlled for sodium) significantly increases SBP, DBP, and PR in humans with normal renal function, in part, by increasing sympathoadrenergic activity.

背景技术尽管流行病学证据表明，高肾功能正常的人饮食和血清磷酸盐水平较高，心血管疾病的发病率和死亡率都会增加，但尚未有关于系统血液动力学的磷酸盐控制干预研究的报道。较高的血清25（OH）维生素D水平与较好的心血管结局相关，但维生素D可增加肠道磷酸盐的吸收。

方法我们对20名肾功能正常的年轻人进行了一项前瞻性门诊研究，并进行了盲法评估，他们随机分配为高磷酸盐（常规饮食加1mmol / kg体重的钠，每天为中性磷酸钠）或低磷酸盐（常规饮食加镧，每天三次，每次750毫克，外加每天0.7毫摩尔/千克体重的NaCl（NaCl），持续11周。6周后，所有受试者均通过肌肉注射获得了维生素D ₃（600,000 U）。结果参数为24小时动态收缩压和舒张压（SBP和DBP），脉搏率（PR），生物标志物以及内皮和动脉功能的测量值。

结果与低磷酸盐饮食组相比，高磷酸盐饮食组的平均±SEM空腹血浆磷酸盐浓度显着增加（0.23±0.11 mmol / L）。24小时SBP和DBP（分别为+4.1； 95％置信区间[95％CI]，为2.1至6.1；和+3.2； 95％CI，分别为1.2至5.2 mm Hg）；平均24小时PR（+4.0; 95％CI，2.0至6.0次/分钟）; 以及尿中肾上腺素和去甲肾上腺素的排泄（分别为54； 95％CI，50至70； 122：95％CI，85至159 µg / 24小时）。维生素D对这些参数均无影响。高磷或低磷饮食和维生素D均不影响内皮功能或动脉弹性。

结论肾功能正常的人增加的磷酸盐摄入量（控制钠盐）可显着增加SBP，DBP和PR，部分原因是通过增加交感神经活性。