80 Participants Needed

Diet and Oxalate Absorption for Kidney Stones

Recruiting at 1 trial location
SF
Overseen BySonia Fargue, PhD
Age: 18+
Sex: Any
Trial Phase: Academic
Sponsor: University of Alabama at Birmingham
No Placebo GroupAll trial participants will receive the active study treatment (no placebo)

Trial Summary

Will I have to stop taking my current medications?

The trial requires participants to stop taking supplements like vitamins, calcium, and herbal supplements for 2 weeks before and during the study. The protocol does not specify if you need to stop other medications, so it's best to discuss with the study team.

What data supports the effectiveness of the treatment for kidney stones?

Research shows that a high calcium diet can help protect against the formation of calcium oxalate stones, which are a common type of kidney stone. Additionally, studies indicate that a high-oxalate diet increases oxalate absorption in the gut, which can contribute to stone formation, suggesting that managing dietary oxalate intake is important for reducing kidney stone risk.12345

Is a high-oxalate diet safe for humans?

Research shows that a high-oxalate diet can increase oxalate absorption in the body, but it does not mention any specific safety concerns for healthy individuals. However, people with a high rate of oxalate absorption or certain intestinal conditions might experience increased urinary oxalate, which could be a risk factor for kidney stones.12678

How does the dietary oxalate treatment for kidney stones differ from other treatments?

This treatment focuses on adjusting dietary oxalate intake to manage kidney stones, which is unique because it targets the absorption of oxalate in the intestines rather than just reducing oxalate excretion. Unlike other treatments, it involves a dietary approach that can either increase or decrease oxalate intake to study its effects on stone formation.128910

What is the purpose of this trial?

The goal of this clinical trial study is to test if patients with idiopathic calcium oxalate kidney stones have an increased absorption of dietary oxalate, which would lead to increased urinary excretion of oxalate.The study will recruit adult patients with a history of calcium oxalate kidney stones and healthy volunteers without kidney stones.Participants will* ingest fixed diets containing low and moderately high amounts of oxalate for 5 days at a time* ingest a soluble form of oxalate and sugar preparations to test gut permeability* collect urine, blood, stool and breath sample during the fixed diets and the soluble oxalate test

Research Team

Sonia Fargue Profile | University of ...

Sonia Fargue, M.D., Ph.D.

Principal Investigator

University of Alabama at Birmingham

Eligibility Criteria

This trial is for adults who've had calcium oxalate kidney stones and healthy volunteers without a history of these stones. Participants will follow specific diets and undergo tests to study how their bodies handle oxalate.

Inclusion Criteria

Body Mass Index > 18.5 kg/m2
Normal fasting serum electrolytes on comprehensive metabolic profile
Willing to ingest fixed diets
See 2 more

Exclusion Criteria

My blood pressure or diabetes is not well-controlled.
My kidney function is severely reduced.
I have type 1 diabetes.
See 7 more

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks
1 visit (in-person)

Low-oxalate diet and initial tests

Participants ingest a controlled low-oxalate diet for 5 days and collect urine samples for analysis

5 days
2 visits (in-person)

13C2-Oxalate gut absorption test

Participants undergo the 13C2-oxalate absorption test with hourly blood and urine collections

1 day
1 visit (in-person)

Wash-out period

Participants have a wash-out period where they eat freely before the next phase

1 week

High-oxalate diet

Participants consume a high-oxalate diet for 4 days and collect urine samples for analysis

4 days
1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after the dietary interventions

2 weeks

Treatment Details

Interventions

  • High-oxalate diet
  • Low-oxalate diet
  • soluble oxalate gut absorption test
Trial Overview The trial involves participants eating low and high-oxalate diets for five days each, taking an oxalate absorption test with sugar solutions, and providing urine, blood, stool, and breath samples to measure the effects.
Participant Groups
2Treatment groups
Experimental Treatment
Active Control
Group I: Idiopathic Calcium Oxalate Kidney Stone PatientsExperimental Treatment3 Interventions
Low and High oxalate fixed diets. Soluble oxalate absorption test.
Group II: Healthy non-kidney stone forming individualsActive Control3 Interventions
Low and High oxalate fixed diets. Soluble oxalate absorption test.

Find a Clinic Near You

Who Is Running the Clinical Trial?

University of Alabama at Birmingham

Lead Sponsor

Trials
1,677
Recruited
2,458,000+

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Collaborator

Trials
2,513
Recruited
4,366,000+

University of Texas Southwestern Medical Center

Collaborator

Trials
1,102
Recruited
1,077,000+

Findings from Research

A study involving 10 healthy participants found that a high calcium diet (1,000 mg daily) led to higher urinary calcium levels and lower urinary oxalate levels compared to a low calcium diet (400 mg daily) while consuming a liberal oxalate diet.
Despite lower oxalate levels, the overall urinary saturation of calcium oxalate was significantly higher on the high calcium diet, suggesting that such a diet may increase the risk of calcium oxalate stone formation.
Effect of high and low calcium diets on stone forming risk during liberal oxalate intake.Matsumoto, ED., Heller, HJ., Adams-Huet, B., et al.[2013]
A high-oxalate diet significantly increases oxalate absorption in healthy individuals, with absorption rates nearly doubling from 7.9% on a low-oxalate diet to 13.7% on a high-oxalate diet, based on a study of 25 volunteers.
After 6 weeks on a high-oxalate diet, oxalate absorption decreased, suggesting that prolonged exposure may lead to adaptation, but absorption rates returned to high levels after a wash-out period, indicating the potential for dietary management in hyperoxaluria.
Influence of a high-oxalate diet on intestinal oxalate absorption.Zimmermann, DJ., Hesse, A., von Unruh, GE.[2018]
In a study of 22 patients with hyperoxaluria, both dietary changes and calcium citrate supplementation significantly reduced urinary oxalate excretion, indicating effective management of this condition.
Importantly, urinary calcium excretion remained unchanged in both groups, suggesting that dietary calcium modifications can help lower oxalate levels without increasing the risk of calcium-related issues.
Effect of dietary changes on urinary oxalate excretion and calcium oxalate supersaturation in patients with hyperoxaluric stone formation.Penniston, KL., Nakada, SY.[2022]

References

Effect of high and low calcium diets on stone forming risk during liberal oxalate intake. [2013]
Influence of a high-oxalate diet on intestinal oxalate absorption. [2018]
Effect of dietary changes on urinary oxalate excretion and calcium oxalate supersaturation in patients with hyperoxaluric stone formation. [2022]
Intestinal oxalate absorption is higher in idiopathic calcium oxalate stone formers than in healthy controls: measurements with the [(13)C2]oxalate absorption test. [2022]
Effect of dietary intake on urinary oxalate excretion in calcium renal stone formers. [2019]
Dietary oxalate and calcium oxalate nephrolithiasis. [2013]
Diet to reduce mild hyperoxaluria in patients with idiopathic calcium oxalate stone formation: a pilot study. [2022]
Effect of dietary oxalate and calcium on urinary oxalate and risk of formation of calcium oxalate kidney stones. [2022]
[13C2]oxalate absorption in children with idiopathic calcium oxalate urolithiasis or primary hyperoxaluria. [2013]
The impact of dietary oxalate on kidney stone formation. [2018]
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