Comparison of Two Diets for the Prevention of Recurrent Stones in Idiopathic Hypercalciuria

Borghi, Loris; Schianchi, Tania; Meschi, Tiziana; Guerra, Angela; Allegri, Franca; Maggiore, Umberto; Novarini, A

doi:10.1056/nejmoa010369

Cited by 860 publications

(558 citation statements)

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“…For patients with Ca oxalate urinary stones who are high oxalate absorbers, the advice to avoid dairy products and to follow a Ca-restricted diet is a recipe for the generation of recurrent Ca oxalate stones. This conclusion, derived from the dependence of the gastrointestinal oxalate absorption from the Ca content of the diet, was recently independently confirmed by a prospective study of 120 patients who formed idiopathic Ca oxalate stones (24).…”

Section: Discussionmentioning

confidence: 73%

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Dependence of Oxalate Absorption on the Daily Calcium Intake

Unruh¹,

Voß

Sauerbruch³

et al. 2004

Journal of the American Society of Nephrology

139

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Abstract. Two to 20% of ingested oxalate is absorbed in the gastrointestinal tract of healthy humans with a daily 800 mg calcium intake. Calcium is the most potent modifier of the oxalate absorption. Although this has been found repeatedly, the exact correlation between calcium intake and oxalate absorption has not been assessed to date. Investigated was oxalate absorption in healthy volunteers applying 0.37 mmol of the soluble salt sodium [ 13 C 2 ]oxalate in the calcium intake range from 5 mmol (200 mg) calcium to 45 mmol (1800 mg) calcium. Within the range of 200 to 1200 mg calcium per day, oxalate absorption depended linearly on the calcium intake. With 200 mg calcium per day, the mean absorption (Ϯ SD) was 17% Ϯ 8.3%; with 1200 mg calcium per day, the mean absorption was 2.6% Ϯ 1.5%. Within this range, reduction of the calcium supply by 70 mg increased the oxalate absorption by 1% and vice versa. Calcium addition beyond 1200 mg/d reduced the oxalate absorption only one-tenth as effectively. With 1800 mg calcium per day, the mean absorption was 1.7% Ϯ 0.9%. The findings may explain why a low-calcium diet increases the risk of calcium oxalate stone formation.For decades, a mainstay in the treatment of patients with calcium (Ca) urinary stones has been a Ca-restricted diet (1). Reduction of the Ca content of the diet reliably reduced the amount of Ca excreted in urine. This reduction was believedbut never proven-to reduce the risk of Ca stone formation. By contrast, already in 1969, a Ca-restricted diet was shown to increase the gastrointestinal absorption of oxalate (2), leading to increased amounts of oxalate in the urine and an increased risk of the formation of Ca oxalate stones. Therefore, to reduce oxalate absorption and the resulting risk of formation of Ca oxalate stones, high-Ca supplements were routinely prescribed to obese patients after ileal bypass surgery (3). The reason why these contradictory and confusing recommendations persisted for so long is the lack of prospective studies and the fact that analysis of oxalate remained unreliable (4) until the mid-1980s. Consequently, the amount of dietary oxalate excreted in urine and its role for renal stone formation were underestimated (5). The fact that a low-Ca diet emerged as a risk factor for Ca oxalate calculi and that a high-Ca diet emerged as a protective factor in two large epidemiologic studies (6,7) is still frequently ignored. Hence, the advice to restrict Ca may still be given to patients with recurrent Ca oxalate urinary stones.We wanted to clear up the confusion generated by the contradictory results as well as the contradictory recommendations, and to answer the following question: To what extent does Ca intake influence the gastrointestinal oxalate absorption? Therefore, we quantitatively measured the dependence of oxalate absorption on Ca intake. The physiologic daily dietary Ca intake lies between approximately 370 and 1200 mg. Intakes of less than 300 mg Ca never occur in adults except in those who reduce food intake to lose weight. ...

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Section: Discussionmentioning

confidence: 73%

“…These increases of urinary Ca in volunteers were by no means critical with respect to Ca oxalate supersaturation. In patients who form Ca stones, however, Ca excretion should be monitored (1,24).…”

Section: Discussionmentioning

confidence: 99%

Dependence of Oxalate Absorption on the Daily Calcium Intake

Unruh¹,

Voß

Sauerbruch³

et al. 2004

Journal of the American Society of Nephrology

139

View full text Add to dashboard Cite

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“…Taken as a whole, these data indicate that patients with hypercalciuria are at risk for bone loss; as a consequence their bone density, as a proxy for calcium balance, should be monitored. A low-calcium diet is not effective in reducing the risk of stone recurrence and poses a substantial risk to maintenance of bone health (137,138).…”

Section: Dent Disease (X-linked Recessive Nephrolithiasis) Dent and mentioning

confidence: 99%

Molecular Mechanisms of Primary Hypercalciuria

Frick¹,

Bushinsky²

2003

Journal of the American Society of Nephrology

127

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“…Studies in mice have shown that induction of acidosis leads to decreased renal tubular expression of the distal tubular apical calcium channel, TRPV5; mice in which the TRPV5 gene was inactivated did not have an increase in calcium excretion with acidosis [33]. Decreasing protein intake (together with a lower salt intake) has been shown to decrease urine calcium excretion and recurrence of calcium stones [34]. However, urine calcium is higher in patients with IH than among normals at comparable levels of acid excretion suggesting that high protein intake worsens but does not usually cause IH.…”

mentioning

confidence: 99%

New Insights Into the Pathogenesis of Idiopathic Hypercalciuria

Worcester

Coe

2008

Seminars in Nephrology

146

125

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Idiopathic hypercalciuria (IH) is the commonest metabolic abnormality in patients with calcium kidney stones. It is characterized by normocalcemia, absence of diseases that cause increased urine calcium, and calcium excretion that is above 250 mg/day in women and 300 mg/day in men. Subjects with IH have a generalized increase in calcium turnover, which includes increased gut calcium absorption, decreased renal calcium reabsorption, and a tendency to lose calcium from bone. Despite the increase in intestinal calcium absorption, negative calcium balance is commonly seen in balance studies, especially on a low calcium diet. The mediator of decreased renal calcium reabsorption is not clear; it is not associated with either an increase in filtered load of calcium or altered PTH levels. There is an increased incidence of hypercalciuria in first-degree relatives of those with IH, but IH appears to be a complex polygenic trait with a large contribution from diet to expression of increased calcium excretion. Increased tissue vitamin D response may be responsible for the manifestations of IH in at least some patients. Definition of HypercalciuriaCalcium, the most abundant cation in human beings, is an important participant in many physiologic processes, including hormonal secretion, cardiac contraction, blood clotting, and neurotransmission. In addition, growth and repair of our skeleton demands an adequate supply of calcium, and careful maintenance of extracellular calcium concentrations. For this reason, prevailing levels of intracellular and extracellular calcium are tightly regulated, by a complex system of control mechanisms. These mechanisms control calcium absorption by gut and renal tubular epithelia, as well as fluxes of calcium on and off bone, during varying dietary calcium intakes. In healthy, non-pregnant adults, whose skeleton is no longer growing, net intestinal calcium absorption is matched by renal excretion, and provides sufficient calcium for skeletal maintenance; however, under pathologic conditions, some urine calcium may derive from bone loss.Abnormalities of calcium homeostasis could result in a number of undesired consequences, including abnormally high or low serum calcium levels, or inadequate maintenance of bone mineral. Hypercalciuria might be defined as any level of urine calcium that exceeds net intestinal absorption, leading to net loss of calcium. However, in practice net intestinal absorption is seldom measured, and under the assumption that urine calcium is primarily derived from intestinal absorption, the working definition of hypercalciuria is urine calcium excretion that exceeds that found in the majority of healthy adults eating their usual diets. In practice, this is usually defined as a daily calcium excretion over 250 mg/day in women or 300Mailing address: Elaine Worcester, M.D., Nephrology Section, Suite 511 / MC 5100, University of Chicago, 5841 S. Maryland Avenue, Chicago, Illinois 60637, Phone: 773-702-7459, Fax: 773-702-5818. Publisher's Disclaimer: This is a PDF file ...

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Comparison of Two Diets for the Prevention of Recurrent Stones in Idiopathic Hypercalciuria

Abstract: In men with recurrent calcium oxalate stones and hypercalciuria, restricted intake of animal protein and salt, combined with a normal calcium intake, provides greater protection than the traditional low-calcium diet.

Cited by 860 publications

References 44 publications

Dependence of Oxalate Absorption on the Daily Calcium Intake

Dependence of Oxalate Absorption on the Daily Calcium Intake

Molecular Mechanisms of Primary Hypercalciuria

New Insights Into the Pathogenesis of Idiopathic Hypercalciuria

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