Biomarker-based studies on the relevance of habitual phosphorus intake and dietary acid load during growth for endocrine and nephrological outcomes in adulthood

• Applicants: Professor Dr. Thomas Remer; Professor Dr. Stefan Alexander Wudy
• Subject Area: Nutritional Sciences ; Anatomy and Physiology ; Nephrology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 464648434

Whether a habitual high phosphorus(P)-intake may result in long-term adverse health outcomes is not yet clarified. Up do now, no population data are available on prospectively examined renal phosphate excretion rates determined in repeatedly – over years – collected 24-h urine samples for the non-invasive assessment of dietary P-intake. Studies are also lacking that examine possible long-term consequences of higher versus lower potential renal acid load (PRAL) for kidney health-relevant outcomes in young adulthood.In the current project, at first, a detailed long-term trend analysis of P intake in healthy children and adolescents in Germany between 1990 and 2019 shall be performed. This analysis will be based on measurements of phosphorus excretion in more than 7000 24-h urine samples collected from 3-17 years old participants of the DONALD study (Dortmund, Germany) during the above period.Potential long-term consequences of a high P-intake during childhood and adolescence will then be examined for different kidney health-relevant outcomes in adulthood. Particularly, specific nephrologic, and endocrine metabolic outcomes, will be analyzed with the aim to assess the prospective importance of higher vs. lower dietary P intake in children and youth. Kidney function in adult DONALD participants will be examined by measuring urinary albumin excretion, glomerular filtration rate, creatinine clearance, renal acid excretion capacity, and circulating uromodulin. The phosphate-regulating hormones parathyroid hormone, fibroblast growth factor 23, and a-Klotho will be additionally determined as well as sympathoadrenergic activity via catecholamine metabolite measurements.Relevant confounding through early life factors, socioeconomic status, anthropometric characteristics, metabolic markers, as well as further potential influencing factors will be allowed for. Additionally, it shall be examined whether at least parts of the observed relationships between P-intake and outcomes could be also explained by a habitual, rather high dietary acid load, quantified – biomarker-based – via PRAL measurements in repeatedly collected 24-h urine samples. Accordingly, preliminary information may be in addition obtained on whether kidney health benefits reported for mainly plant-based, at least partly alkalizing diets like the mediterranean or the DASH diet may be contributorily caused by a habitually reduced dietary acid load.

• DFG Programme: Research Grants