Patients with calcium oxalate kidney stones and enteric hyperoxaluria have significantly higher rates of hypocitraturia, hypomagnesuria, and low urine volume compared to individuals without these conditions, even when consuming a standardized balanced diet.

When the intestine cannot absorb fat properly, it loses bile acids, which causes calcium to bind to fat instead of oxalate. This leaves more oxalate free to be absorbed into the blood, increasing oxalate in the urine. At the same time, the intestine loses bicarbonate, making the blood more acidic. The kidneys respond by excreting more acid and holding onto less citrate, which lowers citrate in the urine. The acidic environment also damages kidney tubules over time, reducing the kidneys' ability to filter fluid, which lowers urine volume. Magnesium levels drop because the body loses it through the gut and cannot retain enough to bind oxalate.