Study of Gut Absorption of Oxalate in Adults with Calcium Oxalate Kidney Stones Compared to Healthy Adults Testing Effects of Low and High Oxalate Diets and Soluble Oxalate Test

What this Trial Is About

Researchers are evaluating whether patients with idiopathic calcium oxalate kidney stones absorb more dietary oxalate, which may cause increased oxalate in their urine. The study includes adults with a history of calcium oxalate kidney stones and healthy volunteers without stones. The aim is to understand oxalate absorption using diets with different oxalate levels and a soluble oxalate test. Participants will follow fixed diets a low-oxalate diet under 60 mgday and a moderately high-oxalate diet 250-300 mgday, each with normal calcium levels. They will complete a soluble oxalate gut absorption test by ingesting labeled oxalate and sucralose. The study involves three phases screening and low-oxalate diet with urine collection a 13C2-oxalate absorption test with blood, urine, breath, and stool samples and a high-oxalate diet phase with urine and blood testing. During the study, participants will provide multiple samples including urine, blood, stool, and breath to measure oxalate absorption and synthesis. They will keep fixed diets for several days and collect urine at home. Researchers will monitor urinary oxalate excretion and absorption of soluble oxalate. The total participation includes diet periods, tests, and sample collections lasting over several weeks, with safety monitoring and wash-out periods between diets.

Gut Oxalate Absorption in Calcium Oxalate Stone Disease