The Medicinal Use of Water in Renal Disease
It is reasonable to inquire whether increased water intake might alter the consumption of other dietary constituents, such as protein and sodium, as such alterations could impact renal function, independent of water intake, over the long term. Although clinical trials designed to answer this specific question are lacking, a few studies, summarized in Table 4, provide insights into this issue. All four studies examined urea excretion (a proxy for protein intake), whereas two (one in non-diseased individuals and one in ADPKD patients) examined total urinary solute excretion and non-urea solute excretion and two (one in nephrolithiasis patients and one in ADPKD patients) examined sodium excretion. In all cases, measured analytes were virtually unchanged despite increased water intake, suggesting that the effects attributable to water were not confounded by changes in other dietary constituents.
Water Intake and Its Effect on Other Dietary Constituents
It is reasonable to inquire whether increased water intake might alter the consumption of other dietary constituents, such as protein and sodium, as such alterations could impact renal function, independent of water intake, over the long term. Although clinical trials designed to answer this specific question are lacking, a few studies, summarized in Table 4, provide insights into this issue. All four studies examined urea excretion (a proxy for protein intake), whereas two (one in non-diseased individuals and one in ADPKD patients) examined total urinary solute excretion and non-urea solute excretion and two (one in nephrolithiasis patients and one in ADPKD patients) examined sodium excretion. In all cases, measured analytes were virtually unchanged despite increased water intake, suggesting that the effects attributable to water were not confounded by changes in other dietary constituents.