Large of evidence indicating that high dietary protein intake raises urinary calcium excretion. However, there have only been a few studies on the effects of reducing protein consumption and the risk of kidney stones formation. A new research out of Italy indicates that a reduction in dietary protein intake could be effective to prevent renal kidney stones formation. This study evaluated the effects of a moderate protein restriction on calcium metabolism in patients with idiopathic hypercalciuria and renal calculi.
This research involve eighteen volunteers with idiopathic hypercalciuria and renal calculi were prescribed an isoenergetic diet consisting of 0.8 g protein per kg of body weight per day, and 955 mg of calcium for 15 days. They were evaluated for serum and urinary measures of calcium metabolism, uric acid, oxalate, citrate, and prostaglandin E2. However, patients with conditions known to affect calcium metabolism were excluded from the study.
Along with this study, a validated dietary questionnaire was administered to all patients. The mean protein intake was 54 g per day. After this moderate protein restriction, serum urea decreased significantly, creatinine clearance showed a tendency toward reduction, which may indicate a decrease in renal mass, as did urinary calcium, uric acid, phosphate, and oxalate excretion. Venous blood pH values and urinary citrate rose significantly.
This research came up with surprising result; one of important fact is concentration of calcitriol fell significantly while parathyroid hormone levels increased significantly. Researchers inferred that calcitriol production had a primary effect on the diet, and that the increase in parathyroid gland activity was a secondary response.
At last, this research was successful to demonstrate that moderate dietary protein restriction reduces calcium excretion in patients with hypercalciuria and calcium nephrolithiasis. Therefore, controlling dietary protein intake may be an essential component in the prevention of renal kidney stones formation.
Compile and re-written based on article by Sandro Giannini, Martino Nobile, Sartori Leonardo
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