Dietary risk factors for hyperoxaluria in calcium oxalate stone formers

• Published in: Kidney international Vol. 63; no. 3; pp. 1037 - 1043
• Main Authors: Siener, Roswitha, Ebert, Dagmar, Nicolay, Claudia, Hesse, Albrecht
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.03.2003; Nature Publishing; Elsevier Limited
• Subjects: Adult; Biological and medical sciences; Calcium - blood; Calcium Oxalate - metabolism; calcium oxalate stone formation; Case-Control Studies; dietary oxalate intake; Female; Follow-Up Studies; Humans; Hyperoxaluria - diet therapy; Hyperoxaluria - epidemiology; Hyperoxaluria - metabolism; Magnesium - urine; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Nutrition Assessment; Oxalates - pharmacokinetics; Potassium - urine; renal stones; Risk Factors; Uric Acid - blood; Urinary Calculi - diet therapy; Urinary Calculi - epidemiology; Urinary Calculi - metabolism; Urinary lithiasis; urinary oxalate excretion; calcium oxalate stone formation; urinary oxalate excretion; dietary oxalate intake; renal stones; Kidney disease; Human; Urinary system disease; Renal function; Pathophysiology; Oxalate; Metabolic diseases; Exploration; Enzymopathy; Kidney; Urinary stone; Genetic disease; Diet; Lithiasis; Hyperoxaluria
• ISSN: 0085-2538; 1523-1755
• DOI: 10.1046/j.1523-1755.2003.00807.x

Dietary risk factors for hyperoxaluria in calcium oxalate stone formers. Hyperoxaluria is a major predisposing factor in calcium oxalate urolithiasis. The aim of the present study was to clarify the role of dietary oxalate in urinary oxalate excretion and to assess dietary risk factors for hyperoxaluria in calcium oxalate stone patients. Dietary intakes of 186 calcium oxalate stone formers, 93 with hyperoxaluria (≥0.5 mmol/day) and 93 with normal oxalate excretion (<0.4 mmol/day), were assessed by a 24-hour weighed dietary record. Each subject collected 24-hour urine during the completion of the food record. Oxalate content of foods was measured by a recently developed analytical method. The mean daily intakes of energy, total protein, fat and carbohydrates were similar in both groups. The diets of the patients with hyperoxaluria were estimated to contain 130 mg/day oxalate and 812 mg/day calcium as compared to 101 mg/day oxalate and 845 mg/day calcium among patients without hyperoxaluria. These differences were not significant. The mean daily intakes of water (in food and beverages), magnesium, potassium, dietary fiber and ascorbic acid were greater in patients with hyperoxaluria than in stone formers with normal oxalate excretion. Multiple logistic regression analysis revealed that urinary oxalate excretion was significantly associated with dietary ascorbate and fluid intake, and inversely related to calcium intake. Differences of estimated diet composition of both groups corresponded to differences in urinary parameters. These findings suggest that hyperoxaluria predominantly results from increased endogenous production and from intestinal hyperabsorption of oxalate, partly caused by an insufficient supply or low availability of calcium for complexation with oxalate in the intestinal lumen.