the Regulation of Phosphorus Homeostasis by Dietary Phosphorus Intake in Normal Men

Serum phosphate concentrations are not only associated with cardiovascular and all-cause mortality in chronic kidney disease (CKD) patients, but also associated with the mortality in community population. Thus, maintaining normal serum phosphate and reducing postprandial fluctuation of serum phosphate are essential for healthy people.

The investigators have conducted a study about the effects of normal diet (phosphorus 1500mg) and low-phosphorus diet (phosphorus 500mg) on phosphorus homeostasis in healthy men. The results showed low-phosphorus diet could significantly reduce serum phosphorus and urine phosphorus level compared to normal diet. However, the levels of serum FGF23 and a-klotho were not different between these two groups.Thus, the investigators want to further explore the effects of high-phosphorus diet (phosphorus 2300mg)on phosphorus homeostasis in healthy men.

Therefore, the investigators plan to conduct a crossover clinical study to evaluate the phosphorus homeostasis modulated by native normal diet, restricted phosphorus diet, high phosphorus diet and then to explore the underlying mechanisms.

Inclusion criteria

• Men aged 18-45 years
• Healthy volunteers: no history of chronic diseases; no active symptoms or physical signs; negative results of electrocardiogram and chest X-ray; biochemical indicators of regular medical examination are within 95%-105% of normal range.
• Willingness to sign the consent form approved by an Institutional Review Board and comply with the study protocol.
• Body mass index ranged within 18.5-24 kg/m2.

Exclusion criteria

• Current history of drug or alcohol abuse as assessed by the principal Investigator.
• Subject has blood donations or blood loss more than 300ml within three months
• Allergic to more than two foods or drugs.
• Subject has psycho-disability or body disability.
• Subject has a condition that in the judgment of the Principal Investigator could potentially pose a health risk to the patient while involved in the study.
• Subject has participated in the other clinical trials at the same time.