Urinary oxalic acid excretion differs after oral loading of rats with various oxalate salts

Hossain, Rayhan Zubair; Ogawa, Yoshihide; Morozumi, Makoto; Sugaya, Kimio; Hatano, Tadashi

doi:10.1046/j.1442-2042.2003.00557.x

Cited by 10 publications

(3 citation statements)

References 15 publications

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“…When calcium salts or two different kinds of milk were given immediately prior to oxalic acid, urinary oxalate excretion was significantly decreased, probably due to the well known mechanism of calcium forming a complex with oxalate and thereby preventing its absorption and urinary excretion. This result is also consistent with our previous finding that urinary oxalate excretion was markedly reduced after simultaneous administration of calcium salt and oxalic acid (28). A small decrease in oxalate excretion over time (when compared with the baseline excretion) after administration of milk alone diets was observed despite prolong fasting, however, further study is required to explain the issue.…”

Section: Discussionsupporting

confidence: 92%

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Milk and calcium prevent gastrointestinal absorption and urinary excretion of oxalate in rats

Hossain

Ogawa²,

Morozumi³

et al. 2003

Front Biosci

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Dietary oxalate plays a very important role in the formation of calcium oxalate stones, and dietary intake of calcium may decrease oxalate absorption and its subsequent urinary excretion. The purpose of the present study was to determine the effect on urinary oxalate excretion of an acute oral calcium load, standard milk, or high-calcium low-fat milk followed by a dose of oxalic acid. Male Wistar rats weighing 180-200 g were divided into 7 groups of 6 rats each. All animals were fasted for about 24 hours, anesthetized, and hydrated with normal saline at 3-4 mL/hour. Then the animals were given 1 mL of normal saline [Control], 10 mg (111.1 micromol) of oxalic acid [Ox alone], 2 mL of standard milk (calcium: 1.16 mg or 29 micromol/mL) [NCa milk], 2 mL of high-calcium low-fat milk (calcium: 2.05 mg or 51.3 micromol/mL) [HCa milk], equimolar calcium (4.44 mg or 111 micromol) followed by 10 mg of oxalic acid [Ca + Ox], 2 mL of high-calcium low-fat milk followed by 10 mg of oxalic acid [HCa milk + Ox], or 2 mL of standard milk followed by 10 mg of oxalic acid [NCa milk + Ox]. All treatments were administered via a gastrostomy. Urine samples were collected by bladder puncture just before administration and at hourly intervals up to 5 hours afterwards. Urinary oxalate was measured by capillary electrophoresis, while urinary calcium, magnesium and phosphorus were measured by inductively coupled plasma spectrometry. Urinary oxalate excretion peaked at 1 hour in the Ox alone group, while it peaked at 2 or 3 hours in the Ca + Ox, HCa milk + Ox, and NCa milk + Ox groups. Urinary oxalate excretion decreased significantly when 10 mg of oxalate was administered immediately after the administration of equimolar calcium, high-calcium low-fat milk, or standard milk. The cumulative urinary oxalate excretion over 5 hours was approximately 13.6%, 3.5%, 1.6%, and 2.4% in the Ox alone, Ca + Ox, HCa milk + Ox, and NCa milk + Ox groups, respectively. In conclusions, this study demonstrated that calcium salt, or dairy products containing calcium (especially high-calcium low-fat milk) could decrease the gastrointestinal absorption and subsequent urinary excretion of oxalate.

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Section: Discussionsupporting

confidence: 92%

“…(Ox, 10 mg of oxalic acid; NCa milk, standard milk; HCa milk, high-calcium & low-fat milk; Ca, calcium salt equimolar to 10 mg of oxalate). salts to oxalate-containing meals can reduce urinary oxalate excretion (14,22,(25)(26)(27)(28).…”

Section: Introductionmentioning

confidence: 99%

Milk and calcium prevent gastrointestinal absorption and urinary excretion of oxalate in rats

Hossain

Ogawa²,

Morozumi³

et al. 2003

Front Biosci

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“…Thus oxalate present in the soluble form is more readily absorbed than oxalate present in the form of CaOx crystals [45]. Mixing oxalate-containing foods with diary produce can reduce the availability of oxalate for absorption.…”

Section: Bioavailability Of Oxalatementioning

confidence: 99%

Role of Dietary Intake and Intestinal Absorption of Oxalate in Calcium Stone Formation

Jaeger¹,

Robertson²

2004

Nephron Physiol

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The factors affecting the urinary excretion of oxalate are critical to the risk of forming calcium oxalate stones. This article reviews the role of dietary and intestinal oxalate in determining the level of oxalate excreted in urine. The amount of oxalate available for absorption throughout the intestine is highly dependent on the state of oxalate (a) in the food ingested, and (b) in the intestinal contents at each section of the intestinal tract since only the soluble form of oxalate can be absorbed. In this respect, the solubility of calcium oxalate (CaOx) under the prevailing conditions is paramount in determining the amount of oxalate available for absorption at any particular site. In turn, the main factors that control how much oxalate is in the soluble form are pH and the concentrations of calcium, magnesium and (indirectly) phosphate. Based on these parameters, a model of the intestine has been constructed which brings together the available evidence on the prevailing concentrations of these various factors at different sites in the intestine after allowing for dietary intake and the concentration of the above ions in intestinal secretions. The model then calculates the likely concentration of oxalate that is in the soluble form at each site and therefore available for passive absorption at that site. The model shows that oxalate is likely to be absorbed in the stomach, although it can be also absorbed in the small intestine, particularly at the distal end (after the absorption of calcium), and in the colon, since, on a normal intake of calcium and phosphate, most of the calcium in the large bowel would be anticipated to be precipitated as calcium phosphate under the prevailing alkaline conditions and high concentration of phosphate. The amount of free oxalate in the colon is also controlled by the presence or absence of Oxalobacter formigenes, an anaerobe that has an obligate requirement for oxalate as a source of energy and cellular carbon.

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Intestinal transport of an obdurate anion: oxalate

Hatch¹,

Freel²

2004

Urol Res

102

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In this review, we focus on the role of gastrointestinal transport of oxalate primarily from a contemporary physiological standpoint with an emphasis on those aspects that we believe may be most important in efforts to mitigate the untoward effects of oxalate. Included in this review is a general discussion of intestinal solute transport as it relates to oxalate, considering cellular and paracellular avenues, the transport mechanisms, and the molecular identities of oxalate transporters. In addition, we review the role of the intestine in oxalate disease states and various factors affecting oxalate absorption.

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Urinary oxalic acid excretion differs after oral loading of rats with various oxalate salts

Cited by 10 publications

References 15 publications

Milk and calcium prevent gastrointestinal absorption and urinary excretion of oxalate in rats

Milk and calcium prevent gastrointestinal absorption and urinary excretion of oxalate in rats

Role of Dietary Intake and Intestinal Absorption of Oxalate in Calcium Stone Formation

Intestinal transport of an obdurate anion: oxalate

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