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Effect of orange juice consumption on urinary stone risk factors
1Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas 75235-8885.
Abstract:
The value of orange juice consumption in kidney stone prevention was examined in 8 healthy men and 3 men with documented hypocitraturic nephrolithiasis. They underwent 3 phases of a metabolic study, a placebo phase and 2 treatment phases in which they ingested either 1.2 l. orange juice (containing 60 mEq. potassium and 190 mEq. citrate per day) with meals or potassium citrate tablets (60 mEq. per day) with water and meals. Compared to potassium citrate, orange juice delivered an equivalent alkali load and caused a similar increase in urinary pH (6.48 versus 6.75 from 5.71) and urinary citrate (952 versus 944 from 571 mg. per day). Therefore, orange juice, like potassium citrate, decreased urinary undissociated uric acid levels and increased the inhibitor activity (formation product) of brushite (calcium phosphate). However, orange juice increased urinary oxalate and did not alter calcium excretion, whereas potassium citrate decreased urinary calcium without altering urinary oxalate. Thus, orange juice lacked the ability of potassium citrate to decrease urinary saturation of calcium oxalate. Overall, orange juice should be beneficial in the control of calcareous and uric acid nephrolithiasis.
Insights
Orange juice may help prevent kidney stones by increasing urinary citrate and pH, similar to potassium citrate. However, it also increases urinary oxalate, potentially limiting its benefit for calcium oxalate stones.
Area of Science:
- Nephrology
- Urology
- Nutritional Science
Background:
- Kidney stones are a common ailment.
- Hypocitraturic nephrolithiasis is a specific type characterized by low urinary citrate.
- Dietary interventions are explored for kidney stone prevention.
Purpose of the Study:
- To evaluate the efficacy of orange juice in preventing kidney stones.
- To compare the effects of orange juice with potassium citrate supplementation.
- To assess the impact on urinary citrate, pH, oxalate, and calcium levels.
Main Methods:
- A metabolic study involving 11 men (8 healthy, 3 with hypocitraturic nephrolithiasis).
- Three study phases: placebo, orange juice consumption (1.2 L/day), and potassium citrate tablets (60 mEq/day).
- Analysis of urinary pH, citrate, oxalate, and calcium excretion.
Main Results:
- Orange juice and potassium citrate provided equivalent alkali loads and increased urinary pH and citrate.
- Both interventions reduced undissociated uric acid and increased brushite inhibitor activity.
- Orange juice increased urinary oxalate, while potassium citrate decreased urinary calcium.
Conclusions:
- Orange juice demonstrates potential benefits for calcareous and uric acid nephrolithiasis due to increased urinary citrate.
- Orange juice's increase in urinary oxalate may limit its effectiveness for calcium oxalate stone prevention.
- Potassium citrate is more effective in reducing urinary calcium and preventing calcium oxalate stones.