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Different dietary calcium intake and relative supersaturation of calcium oxalate in the urine of patients forming renal stones.

Abstract

1. Dietary calcium restriction, an efficient practice in reducing urinary calcium excretion, has been reported to induce either an increase or no change in oxalate excretion, questioning its use in hypercalciuric stone-forming patients. In addition, calcium restriction has been previously demonstrated to induce other urinary changes which might influence the relative supersaturation of calcium oxalate. So the overall effect of calcium deprivation on the relative supersaturation of calcium oxalate is unpredictable. 2. The aim of the study was to evaluate the effect of dietary calcium restriction on the relative supersaturation of calcium oxalate in the urine of stone-forming patients utilizing a computer methodology which takes into account the main soluble complex species of oxalate. 3. We studied 34 stone-forming patients on both a free-choice diet, whose Ca and oxalate content (24 and 1.2 mmol respectively) was assessed by dietary inquiry, and after 30 days on a prescribed low-calcium and normal oxalate diet (11 and 1.1 mmol respectively). Under both conditions, the excretion of the main urinary parameters related to dietary composition, electrolytes, oxalate and daily citrate urinary excretion, were measured. The relative supersaturation of calcium oxalate was calculated by means of an iterative computer method which takes into account the main soluble complex species on which the solubility of calcium oxalate is dependent. In addition, intact parathyroid hormone and 1,25-dihydroxyvitamin D blood levels were also evaluated. In 13 of the patients intestinal calcium absorption was evaluated during both a free- and a low-calcium diet, utilizing kinetics methodology. 4. The low-calcium diet induced, together with an expected reduction of calcium excretion, a marked increase in oxalate urinary output. This finding was independent of the presence or otherwise of hypercalciuria and of the serum levels of parathyroid hormone and vitamin D. Intestinal calcium absorption was also stimulated by calcium deprivation and its levels were well correlated with oxalate excretion. Minor changes in magnesium and citrate excretion were also observed. The overall effect on the relative supersaturation of calcium oxalate consisted in a substantial increase in this parameter during the low-calcium diet. 5. In conclusion, our data reinforce the concept that dietary calcium restriction has potentially deleterious effects on lithogenesis, by increasing the relative supersaturation of calcium oxalate.

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  • Authors+Show Affiliations

    ,

    Nephrology, Dialysis and Transplantation Department, Ospedale S. Maria della Misericordia, Udine, Italy.

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    Source

    MeSH

    Adult
    Calcium
    Calcium Oxalate
    Calcium, Dietary
    Citric Acid
    Female
    Humans
    Hydroxyproline
    Intestinal Absorption
    Kidney Calculi
    Magnesium
    Male
    Middle Aged
    Oxalates
    Uric Acid
    Urine

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    9337641

    Citation

    Messa, P, et al. "Different Dietary Calcium Intake and Relative Supersaturation of Calcium Oxalate in the Urine of Patients Forming Renal Stones." Clinical Science (London, England : 1979), vol. 93, no. 3, 1997, pp. 257-63.
    Messa P, Marangella M, Paganin L, et al. Different dietary calcium intake and relative supersaturation of calcium oxalate in the urine of patients forming renal stones. Clin Sci. 1997;93(3):257-63.
    Messa, P., Marangella, M., Paganin, L., Codardini, M., Cruciatti, A., Turrin, D., ... Mioni, G. (1997). Different dietary calcium intake and relative supersaturation of calcium oxalate in the urine of patients forming renal stones. Clinical Science (London, England : 1979), 93(3), pp. 257-63.
    Messa P, et al. Different Dietary Calcium Intake and Relative Supersaturation of Calcium Oxalate in the Urine of Patients Forming Renal Stones. Clin Sci. 1997;93(3):257-63. PubMed PMID: 9337641.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Different dietary calcium intake and relative supersaturation of calcium oxalate in the urine of patients forming renal stones. AU - Messa,P, AU - Marangella,M, AU - Paganin,L, AU - Codardini,M, AU - Cruciatti,A, AU - Turrin,D, AU - Filiberto,Z, AU - Mioni,G, PY - 1997/10/24/pubmed PY - 1997/10/24/medline PY - 1997/10/24/entrez SP - 257 EP - 63 JF - Clinical science (London, England : 1979) JO - Clin. Sci. VL - 93 IS - 3 N2 - 1. Dietary calcium restriction, an efficient practice in reducing urinary calcium excretion, has been reported to induce either an increase or no change in oxalate excretion, questioning its use in hypercalciuric stone-forming patients. In addition, calcium restriction has been previously demonstrated to induce other urinary changes which might influence the relative supersaturation of calcium oxalate. So the overall effect of calcium deprivation on the relative supersaturation of calcium oxalate is unpredictable. 2. The aim of the study was to evaluate the effect of dietary calcium restriction on the relative supersaturation of calcium oxalate in the urine of stone-forming patients utilizing a computer methodology which takes into account the main soluble complex species of oxalate. 3. We studied 34 stone-forming patients on both a free-choice diet, whose Ca and oxalate content (24 and 1.2 mmol respectively) was assessed by dietary inquiry, and after 30 days on a prescribed low-calcium and normal oxalate diet (11 and 1.1 mmol respectively). Under both conditions, the excretion of the main urinary parameters related to dietary composition, electrolytes, oxalate and daily citrate urinary excretion, were measured. The relative supersaturation of calcium oxalate was calculated by means of an iterative computer method which takes into account the main soluble complex species on which the solubility of calcium oxalate is dependent. In addition, intact parathyroid hormone and 1,25-dihydroxyvitamin D blood levels were also evaluated. In 13 of the patients intestinal calcium absorption was evaluated during both a free- and a low-calcium diet, utilizing kinetics methodology. 4. The low-calcium diet induced, together with an expected reduction of calcium excretion, a marked increase in oxalate urinary output. This finding was independent of the presence or otherwise of hypercalciuria and of the serum levels of parathyroid hormone and vitamin D. Intestinal calcium absorption was also stimulated by calcium deprivation and its levels were well correlated with oxalate excretion. Minor changes in magnesium and citrate excretion were also observed. The overall effect on the relative supersaturation of calcium oxalate consisted in a substantial increase in this parameter during the low-calcium diet. 5. In conclusion, our data reinforce the concept that dietary calcium restriction has potentially deleterious effects on lithogenesis, by increasing the relative supersaturation of calcium oxalate. SN - 0143-5221 UR - https://www.unboundmedicine.com/medline/citation/9337641/Different_dietary_calcium_intake_and_relative_supersaturation_of_calcium_oxalate_in_the_urine_of_patients_forming_renal_stones_ L2 - http://clinsci.org/cgi/pmidlookup?view=long&pmid=9337641 DB - PRIME DP - Unbound Medicine ER -