Division of Nephrology, National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Division of Nutrition, National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
Key Lab of Medical Molecular Virology & Institute for Basic Research on Aging and Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.
J Ren Nutr. 2021 Sep;31(5):448-458. doi: 10.1053/j.jrn.2020.11.004. Epub 2021 Feb 25.
During the past few decades, phosphorus intake has dramatically increased along with higher protein intake and overuse of inorganic phosphate additives worldwide. The detrimental effects of overconsumption of phosphorus are well recognized for patients with chronic kidney disease (CKD), and dietary phosphorus restriction was recommended for these patients. However, the effects of dietary phosphorus restriction in healthy people have not been fully studied.
In this open-label crossover study, healthy adult men (n = 12) consumed normal phosphorus diet (NPD, 1,500 mg/d) for five days. After a 10-day washout period, healthy adults took low phosphorus diet (LPD, 500 mg/d) for another five days. On the fifth day of each intervention, blood, urine and saliva samples were collected at ten time points, and fecal specimens were collected for bacterial taxa identification.
We found that 24-h mean levels of serum phosphate (Pi), urinary Pi, serum parathyroid hormone and fibroblast growth factor 23 decreased, while serum calcium (Ca) and 1,25-dihydroxy vitamin D increased significantly under LPD compared with those under NPD. Dietary phosphorus intake did not change salivary Pi, urinary Ca, salivary Ca and magnesium (Mg) metabolism. Compared with NPD, LPD increased the relative abundance of beneficial microbes including Bacteroidetes, Ruminococcaceae and Lachnospiraceae, indicating that multiple bacterial metabolic pathways have been shifted.
Full-scale data of dietary phosphorus restriction on Pi, Ca and Mg metabolism in healthy male adults are provided. More importantly, for the first time, dietary phosphorus restriction was found to reshape the intestinal microbiome, which provides information for benefits of dietary phosphorus restriction in healthy people, and potential clues for treating patients with CKD.
在过去几十年中，随着全球范围内蛋白质摄入量的增加和无机磷酸盐添加剂的过度使用，磷的摄入量大幅增加。对于慢性肾脏病（CKD）患者，过度摄入磷的有害影响已得到充分认识，建议这些患者限制饮食中的磷。然而，饮食中限制磷对健康人群的影响尚未得到充分研究。
在这项开放标签的交叉研究中，健康成年男性（n=12）连续 5 天摄入正常磷饮食（NPD，1500mg/d）。在 10 天洗脱期后，健康成年人又摄入 5 天低磷饮食（LPD，500mg/d）。在每个干预的第 5 天，在 10 个时间点采集血液、尿液和唾液样本，并收集粪便标本进行细菌分类鉴定。
我们发现，与 NPD 相比，LPD 可使 24 小时平均血清磷酸盐（Pi）、尿 Pi、血清甲状旁腺激素和成纤维细胞生长因子 23 水平降低，而血清钙（Ca）和 1,25-二羟维生素 D 水平升高。饮食磷摄入量并未改变唾液 Pi、尿 Ca、唾液 Ca 和镁（Mg）代谢。与 NPD 相比，LPD 增加了有益微生物的相对丰度，包括拟杆菌门、瘤胃球菌科和毛螺菌科，表明多种细菌代谢途径发生了转变。
提供了饮食限制磷对健康成年男性 Pi、Ca 和 Mg 代谢的全面数据。更重要的是，首次发现饮食限制磷可重塑肠道微生物群，为饮食限制磷对健康人群的益处提供了信息，并为治疗 CKD 患者提供了潜在线索。
