Acute Effect of High Fat Intake on Urinary Acidification Parameters

Introduction: . We tested whether the provision of free fatty acids (FFAs) as an alternative nonnitrogen energy source (substrate switch) reduces renal ammoniagenesis in uric acid stone formers (UASFs) compared with non-stone forming controls (Ctrls). Methods: Seven UASFs and 8 Ctrls were equilibrated on a fixed metabolic diet for 4 days. After sampling fasting urine and blood, the subjects received oral fat load over 10 hours, with blood and urine samples collected every 2 hours. Results: = 0.002) and decreased significantly in both groups during the 10-hour fat load. Conclusion: excretion defect consistent with lipotoxic impairment of proximal tubule function. Although dietary fat affects ammoniagenesis or excretion, dietary fat restriction alone is likely insufficient for managing the aciduria in UASFs.