Effect of Salt Intervention on Serum Levels of Fibroblast Growth Factor 23 (FGF23) in Chinese Adults: An Intervention Study

BACKGROUND: Fibroblast growth factor 23 (FGF23), a prominent regulator of phosphate and calcium metabolism, regulates sodium excretion in distal tubules through sodium-chloride cotransporter. This effect regulates blood pressure. Salt intake exerts effects on serum levels of FGF23 in mice. The aim of this study was to explore whether salt intervention affects serum concentrations of FGF23 in Chinese adults. MATERIAL/METHODS: We enrolled 44 participants from Lantian, a rural community of Shaanxi, China. All participants were maintained on a three-day normal diet, which was sequentially followed by a seven-day low-Na(+) diet and seven-day high-Na(+) diet. Serum FGF23 concentrations were assessed by ELISA. RESULTS: Serum FGF23 concentrations elevated during low-salt diet compared with levels at baseline (66.20±44.21 pg/mL versus 86.77±53.74 pg/mL, p<0.05) and remarkably decreased when changed from low to high salt intake (86.77±53.74 pg/mL versus 49.26±42.67 pg/mL, p<0.001). Responses of FGF23 to salt intervention were more prominent in normotensive, older than 60 years, BMI <24 kg/m(2) and salt-resistant individuals. Furthermore, a significant inverse correlation was observed between 24-hour urinary sodium and serum concentrations of FGF23 after adjusting age, sex, BMI and hypertension status. CONCLUSIONS: Dietary salt intervention significantly affects serum FGF23 in Chinese adults.