Oxalate-Controlled Diets for Kidney Stones
Recruiting in Palo Alto (17 mi)
Age: 18 - 65
Sex: Any
Travel: May Be Covered
Time Reimbursement: Varies
Trial Phase: Academic
Recruiting
Sponsor: University of Alabama at Birmingham
Must be taking: Thiazides, Citrate supplementation
Must not be taking: Antibiotics, Allopurinol
Disqualifiers: Tobacco use, Pregnancy, Active illness, others
No Placebo Group
Trial Summary
What is the purpose of this trial?This study is looking to understand the role of oxalate on kidney stone development and immunity. This study will enroll healthy participants and participants with calcium oxalate kidney stones (CaOx KS). Participants will be in this study for about 3 weeks, consume controlled diets, and provide blood and urine specimens.
Do I have to stop taking my current medications for the trial?
The trial requires that if you are on medications for kidney stone prevention, you must be on a stable dose for at least 8 weeks before and during the study. You should not take allopurinol for 2 weeks before the study. Other medications are not specifically mentioned, so it's best to discuss with the study team.
What data supports the effectiveness of oxalate-controlled diets for kidney stones?
Research shows that a low oxalate diet can significantly reduce the amount of oxalate in urine, which is a key factor in forming calcium oxalate kidney stones. Studies found that patients on a low oxalate diet had a greater reduction in urinary oxalate compared to those taking supplements, suggesting that dietary changes are effective in managing kidney stone risk.
12345Is an oxalate-controlled diet safe for humans?
Oxalate-controlled diets, which involve adjusting the intake of foods high in oxalate, are generally safe for humans. However, it's important to balance calcium intake, as restricting calcium can increase oxalate absorption, potentially leading to kidney stones. Always consult with a healthcare provider before making significant dietary changes.
46789How does an oxalate-controlled diet differ from other treatments for kidney stones?
An oxalate-controlled diet is unique because it focuses on managing the intake of oxalate-rich foods to reduce the risk of calcium oxalate kidney stones, unlike other treatments that may not address dietary factors. Increasing dietary calcium can help bind oxalate in the gut, reducing its absorption and excretion, which is a different approach compared to medications or surgical interventions.
126810Eligibility Criteria
This trial is for adults aged 18-60 with a BMI of 20-30, not using tobacco or pregnant. It includes healthy individuals and those with calcium oxalate kidney stones who are willing to follow specific diets provided by the study and avoid vigorous exercise. Participants must be able to give informed consent, have normal blood tests, and collect accurate urine samples.Inclusion Criteria
Willing to consume diets provided only by the UAB CCTS Bionutrition Core
I am between 18 and 60 years old.
You need to have normal results for certain blood and urine tests taken after fasting.
+10 more
Exclusion Criteria
I have taken medications or supplements recently and do not have conditions affecting oxalate processing.
I have not had any infections like COVID-19 or the flu in the last 14 days.
I do not meet all the required conditions or my doctor advised against it.
+6 more
Trial Timeline
Screening
Participants are screened for eligibility to participate in the trial
1 week
Dietary Intervention
Participants receive either a high or low oxalate diet for 4 days, followed by a 6-day washout period, and then crossover to the opposite diet for another 4 days
14 days
Daily monitoring for dietary adherence
Follow-up
Participants are monitored for changes in urinary oxalate, nanocrystalluria, and monocyte subtypes
1 week
Final assessment on Day 14
Participant Groups
The study aims to understand how dietary oxalate affects kidney stone formation and immune responses. For about three weeks, participants will consume either a low or high oxalate diet while providing blood and urine samples for analysis.
2Treatment groups
Experimental Treatment
Group I: Healthy ParticipantsExperimental Treatment2 Interventions
Healthy participants will randomly receive either high (250mg) or low (40mg) oxalate diet for for four days, a ten day "washout" period on a self-selected diet, and finally the opposite diet from the first for the last four days.
Group II: Calcium Oxalate Kidney StoneExperimental Treatment2 Interventions
Calcium oxalate kidney stone participants will randomly receive either high (250mg) or low (40mg) oxalate diet for for four days, a ten day "washout" period on a self-selected diet, and finally the opposite diet from the first for the last four days.
Find a Clinic Near You
Research Locations NearbySelect from list below to view details:
University of Alabama at BirminghamBirmingham, AL
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Who Is Running the Clinical Trial?
University of Alabama at BirminghamLead Sponsor
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)Collaborator
National Institutes of Health (NIH)Collaborator
References
Effect of high and low calcium diets on stone forming risk during liberal oxalate intake. [2013]Recent studies suggest that a high calcium diet protects against calcium oxalate stone formation. We compared the effect of high and low calcium diets on urinary saturation of calcium oxalate during liberal oxalate intake.
Effect of dietary changes on urinary oxalate excretion and calcium oxalate supersaturation in patients with hyperoxaluric stone formation. [2022]To test the hypothesis that patients with hyperoxaluria, who modified their dietary calcium intake, would reduce their urinary oxalate excretion without raising their urinary calcium excretion. Diet is a major factor in idiopathic calcium oxalate urolithiasis, yet controversy exists regarding the ideal clinical recommendations. Approximately 20% of patients with calcium oxalate stone formation have hyperoxaluria (> or = 45 mg oxalate/d). Calcium supplements to bind dietary oxalate have been suggested, but clinical evidence of this therapy is lacking.
Prospective Randomized Evaluation of Idiopathic Hyperoxaluria Treatments. [2022]Purpose: Calcium oxalate (CaOx) stone formation is influenced by urinary oxalate excretion. Stone formers with elevated urinary oxalate are commonly prescribed a low-oxalate diet or oral supplementation with vitamin B6 and magnesium to reduce urinary oxalate excretion. This study aims to compare the effects of dietary modification vs supplementation vs a combination of both on urinary oxalate. Materials and Methods: We enrolled patients with a documented history of CaOx stones and newly diagnosed idiopathic hyperoxaluria. Patients were randomized into three treatment groups: low oxalate diet (D), supplementation with 25 mg vitamin B6 and 400 mg magnesium oxide (S), or both low oxalate diet and B6/magnesium supplementation (DS). Baseline and 3-month postintervention 24-hour urine tests were obtained. The primary endpoint was change in 24-hour urinary oxalate (Ox24) at 12 weeks. Secondary endpoints included changes in other 24-hour urine parameters, compliance rates, and adverse effect rates. Results: In total, 164 patients were recruited and 62, 47, and 55 were enrolled into the D, S, and DS groups, respectively. Of these, 99 patients completed the study (56.5% of the D, 72.3% of the S, and 54.6% of the DS groups, respectively). Significant differences were noted in median percent reduction in Ox24 values (-31.1% vs -16.0% vs -23.9%, p = 0.007) in the D, S, and DS groups, respectively. Furthermore, the percentages of patients within each treatment arm who realized a decrease in Ox24 were also found to be significantly different: D = 91.4% vs. S = 67.6% vs DS = 86.7%, p = 0.027. No significant adverse events were observed in any of the study arms. Conclusion: Low oxalate diet is more effective than B6/magnesium supplementation at lowering urinary oxalate in idiopathic hyperoxaluric stone formers. Combination therapy did not produce greater reductions in urinary oxalate than either of the monotherapy arms suggesting it is of little clinical utility. Further study with long-term longitudinal follow-up is required to determine if these treatment strategies reduce recurrent stone events in this population.
Dietary oxalate and calcium oxalate nephrolithiasis. [2013]Patients with calcium oxalate kidney stones are advised to decrease the consumption of foods that contain oxalate. We hypothesized that a cutback in dietary oxalate would lead to a decrease in the urinary excretion of oxalate and decreased stone recurrence. We tested the hypothesis in an animal model of calcium oxalate nephrolithiasis.
Calcium oxalate kidney stones: another reason to encourage moderate calcium intakes and other dietary changes. [2013]Conventional medical thought several decades ago was to restrict the amount of calcium intake in individuals with a history of calcium oxalate stones. In the past decade, several studies have suggested that increasing the intake of calcium may actually reduce the risk of calcium oxalate stone formation. The largest randomized trial of diet and stone recurrence was recently completed. Interestingly, individuals that had normal calcium intakes and lower intakes of protein and salt had a significantly reduced rate of calcium oxalate stone recurrence. This recent trial along with several past epidemiologic studies should be discussed with patients at high risk of stone recurrence. Currently, health professionals have a wealth of information that can be distributed to individuals at high risk of nephrolithiasis, and simple dietary recommendations may be one of the best ways to reduce the risk of calcium oxalate stones.
Effect of dietary oxalate and calcium on urinary oxalate and risk of formation of calcium oxalate kidney stones. [2022]Dietary restriction of oxalate intake has been used as therapy to reduce the risk of recurrence of calcium oxalate kidney stones. Although urinary oxalate is derived predominantly from endogenous synthesis, it may also be affected by dietary intake of oxalate and calcium. The risk of increasing urinary oxalate excretion by excessive consumption of dietary oxalate is greatest in individuals with a high rate of oxalate absorption, both with and without overt intestinal disease. Although oxalate-rich foods enhanced excretion of urinary oxalate in normal volunteers, the increase was not proportional to the oxalate content of the food. Only eight foods--spinach, rhubarb, beets, nuts, chocolate, tea, wheat bran, and strawberries--caused a significant increase in urinary oxalate excretion. Restriction of dietary calcium enhances oxalate absorption and excretion, whereas an increase in calcium intake may reduce urinary oxalate excretion by binding more oxalate in the gut. This review of the literature indicates that initial dietary therapy for stone-forming individuals can be limited to the restriction of foods definitely shown to increase urinary oxalate. The effects of oxalate-restricted diets on urinary oxalate should be evaluated by means of laboratory analyses of urine composition. Subsequent long-term therapy can be recommended if beneficial results are obtained from oxalate restriction at an appropriate calcium intake.
Dietary factors and kidney stone formation. [2013]Kidney stone disease is a substantial health problem associated with significant pain and suffering, as well as economic costs. Over $2 billion were spent in 1986 on stone disease, the majority on treatment of existing stones and only a small percentage on prevention. Clearly, efforts to prevent or at least reduce the likelihood of developing a kidney stone would be an important component of the care of patients at risk. In particular, modifiable dietary factors appear to play an important role in the formation of calcium oxalate stones--the type of stone formed in the vast majority of cases. Once secondary causes of stone formation, such as hyperparathyroidism and renal tubular acidosis, are excluded, dietary counselling is a prudent and effective element of the therapeutic regimen and kidney stone prevention program. Specifically, for individuals who have a history of a calcium-containing kidney stone, important dietary recommendations should include the following: Achieve adequate fluid intake to produce at least 2 liters of urine per day. Avoid calcium restriction (except in the rare instances of excessive intake of greater than several grams per day). It is recommended a dietary intake of elemental calcium of at least 800 mg/day (the current RDA for adults) to prevent a negative calcium balance, bone mineral loss, and increased intestinal absorption of oxalate. At present, there is no evidence to support the belief that calcium restriction is beneficial and current data suggest that it may in fact be harmful.(ABSTRACT TRUNCATED AT 250 WORDS)
Influence of a high-oxalate diet on intestinal oxalate absorption. [2018]Hyperoxaluria is a major risk factor for renal stones. In most cases, it is sustained by increased dietary loads. In healthy individuals with a normal Western diet, the majority of urinary oxalate is usually derived from endogenous metabolism. However, up to 50% may be derived from the diet. We were interested in the effect of a high-oxalate diet on oxalate absorption, not merely on the frequently studied increased oxalate excretion. In study I, 25 healthy volunteers were tested with the [13C2]oxalate absorption test once while following a low-oxalate (63 mg) and once while following a high-oxalate (600 mg) diet for 2 days each. In study II, four volunteers repeated study I, and afterwards continued with a high-oxalate diet (600 mg oxalate/day) for 6 weeks. In the last week, the [13C2]oxalate absorption test was repeated. After 4 weeks of individual normal diet, the oxalate absorption test with a high-oxalate diet was performed again. The results of study I show that the mean [13C2]oxalate absorption under low-oxalate diet was 7.9 +/- 4.0%. In the presence of oxalate-rich food, the percent absorption for the soluble labelled oxalate almost doubled (13.7 +/- 6.3%). The results of study II show that the mean [13C2]oxalate absorption of the four volunteers under low-oxalate diet was 7.3 +/- 1.4%. The absorption increased to 14.7+/-5.2% under 600 mg oxalate. After 6 weeks under a high-oxalate diet, the [13C2]oxalate absorption was significantly decreased (8.2 +/- 1.7%). After the wash-out phase, the absorption was again high (14.1 +/- 2.2%) under the 600 mg oxalate challenge.
Medical management of urinary stone disease. [2022]A variety of dietary and metabolic factors may contribute or cause stone formation in idiopathic calcium oxalate nephrolithiasis. Dietary factors include a high intake of animal proteins, oxalate and sodium, and a low intake of fluids and potassium-containing citrus products. Some of the metabolic causes of stones are hypercalciuria, hypocitraturia, gouty diathesis, hyperoxaluria, and hyperuricosuria. Dietary modification, to be applied in all patients with stones includes a high fluid intake, restriction of oxalate and sodium, and balanced diet with animal proteins complemented by adequate intake of fruits and vegetables. When dietary modification is ineffective in controlling stone formation or in the presence of severe metabolic derangements, a pharmacologic intervention may be necessary. In a simple approach, thiazide or indapamide with potassium citrate is recommended for patients with hypercalciuria, and potassium citrate alone for the remaining normocalciuric subjects.
Diet to reduce mild hyperoxaluria in patients with idiopathic calcium oxalate stone formation: a pilot study. [2022]To assess whether a normal-calcium, low-animal protein, low-salt diet is effective in reducing hyperoxaluria in idiopathic calcium oxalate nephrolithiasis compared with a traditional low-oxalate diet, routinely recommended by clinicians