Effect of dietary treatment and fluid intake on the prevention of recurrent calcium stones and changes in urine composition: A meta-analysis and systematic review.

To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) for investigating the effect of dietary treatment and fluid intake on the prevention of recurrent calcium stones and changes in urine composition. PubMed, Web of Science, Embase, EBSCO, and Cochrane Library databases (updated November 2020) were searched for studies with the following keywords: diet, fluid, recurrent, prevention, randomized controlled trials, and nephrolithiasis. The search strategy and study selection process was conducted by following the PRISMA statement. Six RCTs were identified for satisfying the inclusion criteria and enrolled in this meta-analysis. Our result showed that low protein with or without high fiber diet intervention does not decrease the recurrence of stone upon comparing with control groups (RR = 2.32, 95% CI = 0.42-12.85; P = 0.34) with significant heterogeneity among the studies (I2 = 81%, P = 0.02). But normal-calcium, low protein, low-salt diet had recurrences did reduced the recurrence compared to normal-calcium diet. And the fluid intake has a positive effect on prevention of recurrent stone formation (RR = 0.39, 95% CI = 0.19-0.80; P = 0.01) with insignificant heterogeneity among the studies (I2 = 9%, P = 0.30). The different components of urine at baseline were reported in four studies. Upon reviewing the low protein with or without high fiber dietary therapy groups, it was found that there were no obvious changes in the 24-hour urine sodium, calcium, citrate, urea, and sulfate. In conclusion, our study shows that the only low protein with or without fiber does not affect recurrence, but low Na, normal Ca diet has a marked effect on reducing recurrence of calcium stone. And fluid intake shows a significant reduction in the recurrence of calcium stone.

Consejos dietéticos y de estilo de vida en pacientes con litiasis urinarias / Dietetic and lifestyle recommendations for stone formers

La nutrición está fuertemente asociada al riesgo de episodios litiásicos. Aparte de la predisposición genética, una dieta correcta y balanceada podría prevenir la incidencia de litiasis renal. Varios estudios han analizado cada componente de la dieta y diferentes dietas para entender mejor su impacto sobre la recurrencia litiásica. Líquidos: Una alta ingesta de fluidos es el factor más importante para la prevención de la enfermedad litiásica y por cada 200 mL de agua, el riesgo de litiasis se reduce un 13%. Los refrescos parecen estar asociados a un mayor riesgo de eventos litiásicos, mientras que la cafeina y los zumos de cítricos no lo están. Calcio: Normalmente la ingesta diaria de calcio con la dieta no excede los 1,2 g. Un consumo balanceado de productos lácteos es capaz de reducir la absorción intestinal y la excreción urinaria de oxalato si lo comparamos con una dieta pobre en calcio, siendo protector para la enfermedad litiásica. Oxalato: La cantidad exacta de oxalato en las diferentes comidas es difícil de estimar debido a su variabilidad, incluso en el mismo alimento. Además, se demostró que la cantidad de oxalato ingerido era solo un factor de riesgo menor para la enfermedad litiásica, mientras que su absorción intestinal está fuertemente influenciada por factores externos como la ingesta de calcio. La restricción de oxalato en la dieta se aconseja solamente en pacientes con aumento probado en su consumo. Sodio: Una ingesta elevada de sodio se asocia tanto con la hipertensión como con la enfermedad cardiaca y el riesgo de litiasis. El consumo elevado de sodio está directamente asociado con la hipercalciuria, tanto en litiásicos cálcicos como en sujetos sanos. Aunque la restricción dietética de sodio a los valores recomendados es deseable en los pacientes litiásicos, es difícil de conseguir debido al alto uso de sodio en la preparación de las comidas. Proteinas: Las proteinas animales están asociadas a un riesgo aumentado para la formación de litiasis, mientras que las vegetales y las de productos lácteos no. Un aumento de consumo de carne se ha asociado a un pH urinario ácido, balance de calcio negativo y reducción de la excrección urinaria de solutos anti-litogénicos. Frutas y vegetales: Las comidas alcalinizantes son uno de los factores más importantes para la protección ante la litiasis. Su consumo aumenta los solutos anti-litogénicos como el citrato, potasio y magnesio. Una dieta rica en frutas y vegetales es muy recomendable para los pacientes litiásicos. Acido úrico: Un consumo elevado de carne está asociado tanto a un aumento de metabolismo de las purinas como a la carga ácida, favoreciendo la nefrolitiasis úrica al reducir el pH urinario y aumentar la excreción urinaria de ácido úrico, especialmente en pacientes afectados por el síndrome metabólico y diabetes. En conclusión, la dieta más efectiva para proteger contra la litiasis es la rica en frutas y vegetales, pobre en proteinas animales y sal, con un consumo balanceado de productos lácteos y, obviamente, con una alta ingesta de líquidos. Estas características hacen que las dietas vegetarianas y la mediterránea sean protectoras y útiles para los pacientes litiásicos, mientras que la dieta occidental sea una dieta de riesgo para la formación de litiasis

Nutrition is tightly associated with the risk of stone events. Apart from genetic predisposition, a correct and balanced diet might prevent incident kidney stones. Several studies analyzed each dietary component and different diets to better understand their impact on stone recurrence. Fluids: High fluids intake is the most important factor for preventing kidney stones disease and for every 200 mL of water, the risk of stones is reduced by 13%. Soft drinks seems to be associated to a greater risk of stone events, whereas caffeine and citrus fruits juice are not. Calcium: Normally calcium intake with diet does not exceed 1.2 g/day. A balanced consumption of dairy products is capable of reducing oxalate intestinal absorption and urinary excretion compared to low calcium diet, being protective for stone disease. Oxalate: The exact amount of oxalate contained in different foods is difficult to estimate for its variability, even in the same aliment. In addition, the amount of oxalate consumed was shown to be only a minor risk factor for stone disease, whereas its intestinal absorption is strongly influenced by external factors, such as calcium intake. Dietary oxalate restriction is advisable only in patients with known elevated consumption. Sodium: High sodium intake is both associated with hypertension, heart disease and stone risk. Increased sodium consumption is directly associated to hypercalciuria in both calcium stone formers and healthy subjects. Although dietary sodium restriction to recommended values is always desirable in stone formers, it is difficult to achieve for its broad use in food preparation. Proteins: Animal proteins are associated to increased risk for stone formation, whereas vegetable and dairy proteins are not. Increased meat intake was associated to acidic urine pH, negative calcium balance and reduced anti-lithogenic urinary solutes excretion. Fruits and vegetables: Alkalizing foods are one of the most important factors for stone protection. Their consumption increases anti-lithogenic solutes as citrate, potassium and magnesium. A diet rich in fruits and vegetables is strongly recommended for stone formers. Uric acid: Elevated meat consumption is either associated to increased purine metabolism and acid load, favoring uric acid nephrolithiasis by reducing urine pH and increasing urinary excretion of uric acid, especially in patients affected by metabolic syndrome and diabetes. In conclusion, the most effective diet for stone protection is rich in fruits and vegetables, low in animal proteins and salt, with balanced dairy product consumption and obviously, with elevated fluid intake. These characteristics make vegetarian and Mediterranean diets protective and useful for stone formers, whereas western diet is at risk for stone formation

The Impact of Dietary Modifications and Medical Management on 24-Hour Urinary Metabolic Profiles and the Status of Renal Stone Disease in Recurrent Stone Formers.

BACKGROUND: Dietary modifications and patient-tailored medical management are significant in controlling renal stone disease. Nevertheless, the literature regarding effectiveness is sparse. OBJECTIVES: To explore the impact of dietary modifications and medical management on 24-hour urinary metabolic profiles (UMP) and renal stone status in recurrent kidney stone formers. METHODS: We reviewed our prospective registry database of patients treated for nephrolithiasis. Data included age, sex, 24-hour UMP, and stone burden before treatment. Under individual treatment, patients were followed at 6-8 month intervals with repeat 24-hour UMP and radiographic images. Nephrolithiasis-related events (e.g., surgery, renal colic) were also recorded. We included patients with established long-term follow-up prior to the initiation of designated treatment, comparing individual nephrolithiasis status before and after treatment initiation. RESULTS: Inclusion criteria were met by 44 patients. Median age at treatment start was 60.5 (50.2-70.2) years. Male:Female ratio was 3.9:1. Median follow-up was 10 (6-25) years and 5 (3-6) years before and after initiation of medical and dietary treatment, respectively. Metabolic abnormalities detected included: hypocitraturia (95.5%), low urine volume (56.8%), hypercalciuria (45.5%), hyperoxaluria (40.9%), and hyperuricosuria (13.6%). Repeat 24-hour UMP under appropriate diet and medical treatment revealed a progressive increase in citrate levels compared to baseline and significantly decreased calcium levels (P = 0.001 and 0.03, respectively). A significant decrease was observed in stone burden (P = 0.001) and overall nephrolithiasis-related events. CONCLUSIONS: Dietary modifications and medical management significantly aid in correcting urinary metabolic abnormalities. Consequently, reduced nehprolithiasis-related events and better stone burden control is expected.

Prevention of recurrent urinary stone disease.

PURPOSE OF REVIEW: Urinary stone disease (USD) is increasing in prevalence and recurrence is common. In pediatrics, most stones are composed primarily of calcium with the highest incidence observed in adolescents. Given the morbidity associated with USD, an in depth review of current management strategies is of paramount importance to highlight the data supporting the recommended treatments and the knowledge gaps which still exist. RECENT FINDINGS: Several interventions for the management of recurrent calcium USD in children have been recommended based on primarily adult studies. These interventions include modification of diet and fluid intake in addition to the utilization of medications such as thiazide diuretics and citrates when supportive care is inadequate. Overall there is conflicting data in the adult literature which is further complicated by our attempts to extrapolate these data to children. SUMMARY: Based on the currently available literature the management of USD in pediatrics should be individualized to each patient and focused on the particular metabolic risk factors that are identified during the course of their evaluation. Several interventions may be required or trialed in a particular patient to show an effect. Well designed trials to assess the efficacy of each intervention in the pediatric population are needed.

Intervención nutricional en el control de la colelitiasis y la litiasis renal / Nutritional intervention in the control of gallstones and renal lithiasis

La colelitiasis y litiasis renal son patologías frecuentes en países desarrollados. Los cálculos biliares pueden ser pigmentarios, de colesterol (75%) o mixtos. La edad, el sexo femenino, la obesidad, la pérdida rápida de peso, el consumo de azúcares refinados, la grasa saturada, la deficiencia de hierro y de vitamina D y la baja ingesta de fibra y vitamina C son factores asociados a mayor riesgo de colelitiasis. Por otro lado, la ingesta de ácidos grasos ω-3, ácido oleico, calcio, magnesio, fibra, frutas y verduras, lácteos, frutos secos, café, un consumo moderado de alcohol, suplementos de vitamina C, ejercicio físico y una alimentación regular desempeñan un papel protector. Las litiasis renales más frecuentes son de oxalato cálcico, seguidas de las mixtas (oxalato y fosfato cálcico), estruvita, ácido úrico y cistina. Se aconseja una elevada ingesta hídrica (> 2,5 l/día), variando el tipo de alimentos recomendados o desaconsejados en función del tipo de cálculo. En litiasis oxálica se recomienda reducir el consumo de carne, moderar el de espinacas, acelgas, espárragos, chocolate y evitar el aporte excesivo de sodio. La administración de probióticos degradantes de oxalato (Lactobacillus) podría reducir su absorción intestinal, aunque son necesarios más estudios para corroborar estos resultados. En las de fosfato cálcico se aconseja dieta acidificante y limitar el consumo de café y té. La prevención de cálculos de úrico está basada en la hidratación con bebidas alcalinizantes y dieta vegetariana, disminuyendo los alimentos ricos en purinas (hígado, riñón, huevas de pescado, anchoas, sardinas y mariscos), y en cálculos de cistina se aconseja el consumo de dietas alcalinizantes. Dado que la formación de cálculos de estruvita se debe a infecciones urinarias, es necesario un tratamiento farmacológico y el consumo de dietas acidificantes, moderar la ingesta de alimentos ricos en fosfatos y limitar el aporte de grasas y cítricos. La intervención nutricional es una medida eficaz en la prevención de la litiasis biliar y renal y para evitar su recurrencia

Cholelithiasis and kidney stones are frequent pathologies in developed countries. Gallstones can be pigmentary, cholesterol (75%) or mixed. Age, female sex, obesity, rapid weight loss, consumption of refined sugars, saturated fat, iron deficiency, vitamin D and low intake of fiber and vitamin C are factors associated with an increased risk of cholelithiasis. On the other hand, the intake of ω-3 fatty acids, oleic acid, calcium, magnesium, fiber, fruits and vegetables, dairy products, nuts, coffee, moderate consumption of alcohol, vitamin C supplements, physical exercise and a regular diet have a protective paper. The most frequent kidney stones are calcium oxalate followed by mixed ones (oxalate and calcium phosphate), struvite, uric acid and cystine. A high water intake is recommended (> 2.5 l / day), varying the type of recommended or unadvisable food depending on the type of calculus. In oxalic lithiasis it is recommended to reduce the consumption of meat, moderate that of spinach, Swiss chard, asparagus, chocolate and avoid excessive sodium intake. The administration of oxalate-degrading probiotics (Lactobacillus) may reduce intestinal absorption, although further studies are necessary to corroborate these results. In calcium phosphate acidifying diet is recommended and limit the consumption of coffee and tea. The prevention of uric calculus is based on hydration with alkalizing drinks and vegetarian diet, decreasing foods rich in purines (liver, kidney, fish eggs, anchovies, sardines and seafood) and in calculus of cystine diet is recommended alkalizing. Since the formation of struvite calculi is due to urinary infections, pharmacological treatment and the consumption of acidifying diets, moderation of the intake of phosphate-rich foods and limiting the contribution of fats and citrus fruits are necessary. The nutritional intervention is an effective measure in the prevention of biliary and renal lithiasis and prevent its recurrence

Dietary vinegar prevents kidney stone recurrence via epigenetic regulations.

BACKGROUND: Epidemiological evidence of over 9000 people suggests that daily intake of vinegar whose principal bioactive component is acetic acid is associated with a reduced risk of nephrolithiasis. The underlying mechanism, however, remains largely unknown. METHODS: We examined the in vitro and in vivo anti-nephrolithiasis effects of vinegar and acetate. A randomized study was performed to confirm the effects of vinegar in humans. FINDINGS: We found individuals with daily consumption of vinegar compared to those without have a higher citrate and a lower calcium excretion in urine, two critical molecules for calcium oxalate (CaOx) kidney stone in humans. We observed that oral administration of vinegar or 5% acetate increased citrate and reduced calcium in urinary excretion, and finally suppressed renal CaOx crystal formation in a rat model. Mechanism dissection suggested that acetate enhanced acetylation of Histone H3 in renal tubular cells and promoted expression of microRNAs-130a-3p, -148b-3p and -374b-5p by increasing H3K9, H3K27 acetylation at their promoter regions. These miRNAs can suppress the expression of Nadc1 and Cldn14, thus enhancing urinary citrate excretion and reducing urinary calcium excretion. Significantly these mechanistic findings were confirmed in human kidney tissues, suggesting similar mechanistic relationships exist in humans. Results from a pilot clinical study indicated that daily intake of vinegar reduced stone recurrence, increased citrate and reduced calcium in urinary excretion in CaOx stone formers without adverse side effects. INTERPRETATION: Vinegar prevents renal CaOx crystal formation through influencing urinary citrate and calcium excretion via epigenetic regulations. Vinegar consumption is a promising strategy to prevent CaOx nephrolithiasis occurrence and recurrence. FUND: National Natural Science Foundations of China and National Natural Science Foundation of Guangdong Province.

Emerging Mobile Platforms to Aid in Stone Management.

Nephrolithiasis is an increasingly common condition worldwide and mobile technology is revolutionizing how patients with kidney stone are being diagnosed and managed. Emerging platforms include software applications to increase adherence to stone prevention, mobile compatible hardware, online social media communities, and telemedicine. Applications and hardware specifically relevant to increasing hydration, diet modification, medication adherence, and rapid diagnosis (ie, mobile ultrasound and endoscopy) have the greatest potential to reduce stone recurrence and expedite treatment. Social media and online communities have also been rapidly adopted by patients and providers to promote education and support.

La dieta en el paciente litiásico: una guía práctica / Diet in the lithiasic patient: A practical guide

La incidencia y prevalencia de la enfermedad litiásica en los países desarrollados ha aumentado en los últimos años. Debido a que la dieta es uno de los factores de riesgo de la urolitiasis, y tanto esta como el estilo de vida han evolucionado en las últimas décadas, dichos cambios podrían explicarnos el aumento en la causística de la litiasis renal. En el presente trabajo analizamos cuál ha sido el proceder del urólogo en cuanto al papel preventivo de la dieta en el paciente litiásico, qué evidencias científicas existen en cuanto a la relación entre dieta y litiasis y, en base a ello, qué recomendaciones generales dietéticas podemos dar actualmente a nuestros pacientes

The incidence and prevalence of lithiasic disease in developed countries has increased over the last years. Being diet one of the risk factors for urolithiasis, and having it evolved in conjunction with lifestyle over the last decades, such changes could explain the increase in lithiasis case-load. In this article, we analyze how the exercise of the urologist has been regarding the preventive role of diet in the lithiasis patient, what are the scientific evidences on the relationship of diet and lithiasis, and, on this base, what general dietetic recommendations we can give currently to our patients

Adecuación de la dieta por razones de salud: intervención enfermera en pacientes con litiasis renal / Adapting the diet due to health reasons: Nursing intervention in patients with renal lithiasis

La litiasis urinaria, de gran incidencia en la actualidad, como la ocasionada por formaciones de cálculos de ácido úrico, tiene una gran relación con nuestros estilos de vida, entre ellos, los hábitos dietéticos. A través de un caso clínico se pretende revisar las principales actuaciones de enfermería que pueden acontecer ante dicha patología. Para lograrlo, se exponen los datos recogidos en la exploración física y valoración enfermera según el modelo de Virginia Henderson, al mismo tiempo que se desarrolla el plan de cuidados completo. Los resultados arrojan la necesidad de instaurar ante esta patología intervenciones estandarizadas de educación para la salud en relación a la alimentación limitada en purinas de las personas que la padecen. La multitud de complicaciones y otros problemas asociados a la estancia hospitalaria dada la reincidencia de litiasis por desconocimiento suponen un riesgo para la calidad de vida de la persona y el mantenimiento de su independencia

The urolithiasis, with a high incidence nowadays, including formations caused by gallstone of uric acid, has a high correlation to our lifestyles and dietary habits. Through a clinic case, it is intended to review the main nursing actions that may occur with this pathology. To achieve this, the data collected on physical examination and nursing assessment on the model of Virginia Henderson, while the full care plan is developed. The results show the need to establish a standardized healthy education intervention, related to a low-pruine healthy diet for people that suffer this disease. The amount of complications and problems associated with recidivism of hospital accommodation because of the ignorance of gallstone cases increase the risk of reducing the quality of life of the patients

[Nutritional management of kidney diseases in children].

The prevalence of various kidney diseases in children remains high in recent decades. Adequate nutrition management can enhance the effectiveness of drug treatment, slow the frequency of relapses andprevent the progression of the disease. The article is devoted to modern approaches to diet therapy in various kidney diseases in children with the defeat of tubular and glomerular appa ratus. For the first time the therapeutic diets for children with various kidney diseases are presented. Particular attention is paid to diet therapy in nephrotic syndrome (steroid-responsive and steroid-refractory). Dietary approaches with modern formulas for enteral nutrition in cases of steroid therapy complications in children with renal insufficiency (in predialysis stage and on dialysis) are described. Differentiated nutritional approaches for patients with different types of crystalluria are separately presented.

Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults: a clinical practice guideline from the American College of Physicians.

DESCRIPTION: The American College of Physicians (ACP) developed this guideline to present the evidence and provide clinical recommendations on the comparative effectiveness and safety of preventive dietary and pharmacologic management of recurrent nephrolithiasis in adults. METHODS: This guideline is based on published literature on this topic that was identified using MEDLINE, the Cochrane Database of Systematic Reviews (through March 2014), Google Scholar, ClinicalTrials.gov, and Web of Science. Searches were limited to English-language publications. The clinical outcomes evaluated for this guideline include symptomatic stone recurrence, pain, urinary tract obstruction with acute renal impairment, infection, procedure-related illness, emergency department visits, hospitalizations, quality of life, and end-stage renal disease. This guideline grades the quality of evidence and strength of recommendations using ACP's clinical practice guidelines grading system. The target audience for this guideline is all clinicians, and the target patient population is all adults with recurrent nephrolithiasis (≥1 prior kidney stone episode). RECOMMENDATION 1: ACP recommends management with increased fluid intake spread throughout the day to achieve at least 2 L of urine per day to prevent recurrent nephrolithiasis. (Grade: weak recommendation, low-quality evidence). RECOMMENDATION 2: ACP recommends pharmacologic monotherapy with a thiazide diuretic, citrate, or allopurinol to prevent recurrent nephrolithiasis in patients with active disease in which increased fluid intake fails to reduce the formation of stones. (Grade: weak recommendation, moderate-quality evidence).

[Nephrolithiasis: metabolic defects and terapeutic implications]. / Nefrolitiasi: aspetti metabolici e implicazioni terapeutiche.

Over the past 10 years, major progress has been made in the knowledge of urinary lithogenesis, including the potential pathogenetic role of Randall's plaques and renal tubular crystal retention. Urine supersaturation is the driving force of this process and can be induced by some risk factors, including low urine volume, high urinary excretion of calcium oxalate and uric acid and low urinary excretion of citrate. Primary hypercalciuria can be due to intestinal overabsorption renal leak and bone reabsorption of calcium. Prophilaxis is mainly conducted with thiazides and low calcium diet which is indicated only in the intestinal form. Primary hyperoxaluria is treated with pyridoxine and may require in the severe forms simultaneous renal and liver transplantation. Enteric hyperoxaluria is secondary to fatty acids malabsorption and requires diet, oral calcium and cholestiramine. Hyperuricosuria is caused by diet endogenous overproduction, mainly due to enzymatic defects or high renal excretion of uric acid. Urine alkalinization with K or K and Mg citrate can prevent stone formation even in idiopathic uric acid nephrolithiasis, in which a defect of urine acidification is supposed to be the main abnormality, and in hypocitraturic patients. Cystinuria is a rare inherited defect with an intense clinical impact. It can be classified in three forms and urinary stone formation is the role. Increased solubility and conversion of cystine in a more soluble form are the main goals of the prophylaxis which includes K citrate and thiol agents administration. Tiopronin is preferred to D-penicillamine due to its lower side effects.

Carbonate apatite nephrolithiasis associated with Corynebacterium urealyticum urinary tract infection in a dog.

BACKGROUND: Urinary tract infections caused by Corynebacterium urealyticum are uncommon in veterinary medicine. Encrusted cystitis, encrusted pyelitis and uroliths have been described as complications in humans, but only encrusted cystitis and cystoliths have been reported in dogs so far. Because C. urealyticum is usually resistant to all standard antibacterial drugs, antimicrobial treatment and elimination of this microorganism are challenging. CASE REPORT: An 11-month-old female spayed mixed-breed dog was evaluated because of a C. urealyticum urinary tract infection, mineralisation within both renal pelvises and failure of antimicrobial treatment. Physical examination, haematology and biochemistry were unremarkable. Radiographic and ultrasonographic examinations confirmed bilateral nephrolithiasis. Voided uroliths were composed of 100% carbonate apatite. Urinalysis was indicative of bacterial infection. Aerobic culture of the urine and 16S rRNA sequencing identified significant growth of C. urealyticum and susceptibility testing revealed sensitivity to only vancomycin and linezolid. CONCLUSION: Treatment with the oxazolidinone antibacterial, linezolid, in combination with a urine-acidifying diet resulted in elimination of this multiresistant microorganism and complete resolution of nephrolithiasis.

Dietary interventions for preventing complications in idiopathic hypercalciuria.

BACKGROUND: Idiopathic hypercalciuria is an inherited metabolic abnormality that is characterised by excessive amounts of calcium excreted in the urine by people whose calcium serum levels are normal. Morbidity associated with idiopathic hypercalciuria is chiefly related to kidney stone disease and bone demineralisation leading to osteopenia and osteoporosis. Idiopathic hypercalciuria contributes to kidney stone disease at all life stages; people with the condition are prone to developing oxalate and calcium phosphate kidney stones. In some cases, crystallised calcium can be deposited in the renal interstitium, causing increased calcium levels in the kidneys. In children, idiopathic hypercalciuria can cause a range of comorbidities including recurrent macroscopic or microscopic haematuria, frequency dysuria syndrome, urinary tract infections and abdominal and lumbar pain. Various dietary interventions have been described that aim to decrease urinary calcium levels or urinary crystallisation. OBJECTIVES: Our objectives were to assess the efficacy, effectiveness and safety of dietary interventions for preventing complications in idiopathic hypercalciuria (urolithiasis and osteopenia) in adults and children, and to assess the benefits of dietary interventions in decreasing urological symptomatology in children with idiopathic hypercalciuria. SEARCH METHODS: We searched the Cochrane Renal Group's Specialised Register (23 April 2013) through contact with the Trials' Search Co-ordinator using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE and EMBASE. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) and quasi-RCTs that investigated dietary interventions aimed at preventing complications of idiopathic hypercalciuria, compared with placebo, no intervention, or other dietary interventions regardless of route of administration, dose or amount. DATA COLLECTION AND ANALYSIS: Studies were assessed for inclusion and data extracted using a standardised data extraction form. We calculated risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes, both with 95% confidence intervals (CI). MAIN RESULTS: We included five studies (379 adult participants) that investigated a range of interventions. Lack of similarity among interventions investigated meant that data could not be pooled. Overall, study methodology was not adequately reported in any of the included studies. There was a high risk of bias associated with blinding (although it seems unlikely that outcomes measures were unduly influenced by lack of intervention blinding), random sequence generation and allocation methodologies were unclear in most studies, but selective reporting bias was assessed as low.One study (120 participants) compared a low calcium diet with a normal calcium, low protein, low salt diet for five years. There was a significant decrease in numbers of new stone recurrences in those treated with the normal calcium, low protein, low salt diet (RR 0.77, 95% CI 0.61 to 0.98). This diet also led to a significant decrease in oxaluria (MD 78.00 µmol/d, 95% CI 26.48 to 129.52) and the calcium oxalate relative supersaturation index (MD 1.20 95% CI 0.21 to 2.19).One study (210 participants) compared a low salt, normal calcium diet with a broad diet for three months. The low salt, normal calcium diet decreased urinary calcium (MD -45.00 mg/d, 95% CI -74.83 to -15.17) and oxalate excretion (MD -4.00 mg/d, 95% CI -6.44 to -1.56).A small study (17 participants) compared the effect of dietary fibre as part of a low calcium, low oxalate diet over three weeks, and found that although calciuria levels decreased, oxaluria increased. Phyllanthus niruri plant substrate intake was investigated in a small subgroup with hypercalciuria (20 participants); there was no significant effect on calciuria levels occurred after three months of treatment.A small cross-over study (12 participants) evaluating the changes in urinary supersaturation indices among patients who consumed calcium-fortified orange juice or milk for one month found no benefits for participants.None of the studies reported any significant adverse effects associated with the interventions. AUTHORS' CONCLUSIONS: Long-term adherence (five years) to diets that feature normal levels of calcium, low protein and low salt may reduce numbers of stone recurrences, decrease oxaluria and calcium oxalate relative supersaturation indexes in people with idiopathic hypercalciuria who experience recurrent kidney stones. Adherence to a low salt, normal calcium level diet for some months can reduce calciuria and oxaluria. However, the other dietary interventions examined did not demonstrate evidence of significant beneficial effects.No studies were found investigating the effect of dietary recommendations on other clinical complications or asymptomatic idiopathic hypercalciuria.

Influence of acidifying or alkalinizing diets on bone mineral density and urine relative supersaturation with calcium oxalate and struvite in healthy cats.

OBJECTIVE: To evaluate the influence of acidifying or alkalinizing diets on bone mineral density and urine relative supersaturation (URSS) with calcium oxalate and struvite in healthy cats. ANIMALS: 6 castrated male and 6 spayed female cats. PROCEDURES: 3 groups of 4 cats each were fed diets for 12 months that differed only in acidifying or alkalinizing properties (alkalinizing, neutral, and acidifying). Body composition was estimated by use of dual energy x-ray absorptiometry, and 48-hour urine samples were collected for URSS determination. RESULTS: Urine pH differed significantly among diet groups, with the lowest urine pH values in the acidifying diet group and the highest values in the alkalinizing diet group. Differences were not observed in other variables except urinary ammonia excretion, which was significantly higher in the neutral diet group. Calcium oxalate URSS was highest in the acidifying diet group and lowest in the alkalinizing diet group; struvite URSS was not different among groups. Diet was not significantly associated with bone mineral content or density. CONCLUSIONS AND CLINICAL RELEVANCE: Urinary undersaturation with calcium oxalate was achieved by inducing alkaluria. Feeding an alkalinizing diet was not associated with URSS with struvite. Bone mineral density and calcium content were not adversely affected by diet; therefore, release of calcium from bone caused by feeding an acidifying diet may not occur in healthy cats.

[Diet in the treatment of renal lithiasis. Pathophysiological basis]. / La dieta en el tratamiento de la litiasis renal. Bases fisiopatológicas.

The composition of urine is influenced by diet and changes in dietary factors have been proposed to modify the risk of recurrent nephrolithiasis. Nutrients that have been implicated include calcium, oxalate, sodium, animal protein, magnesium and potassium. There is significant evidence showing that a high calcium diet is associated with a reduction of lithogenic risk. One of the possible mechanisms to explain this apparent paradox is that the higher intake of calcium in the intestine binds with dietary oxalate, reducing its absorption and urinary excretion. Oxalate from the diet seems to provide only a small contribution to excretion and dietary restriction is appropriate only in those with hyperoxaluria and hyperabsorption. Observational studies have shown a positive and independent association between sodium intake and the formation of new kidney stones. Consumption of animal protein creates an acid load that increases urinary excretion of calcium and uric acid and reduced citrate, all factors that could participate in the genesis of stones. Potassium-rich foods increase urinary citrate because of its alkali content. In prospective observational studies, diets rich in magnesium were associated with a lower risk of kidney stone formation in men. In conclusion, diet is a key element in the management of the patient with kidney stones but always subordinated to present metabolic risk factors.