Diet Impact on Kidney Stones in Obese Individuals

Recruiting at 1 trial location

Overseen By Naim Maalouf, MD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Alabama at Birmingham

Must not be taking: Immunosuppressants, Antibiotics

Disqualifiers: Diabetes, Gout, Liver disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

22 Participants Needed

Trial Summary

What is the purpose of this trial?

The primary goals of this study are to determine the contribution of dietary oxalate absorption, renal oxalate handling, and endogenous oxalate synthesis to urinary oxalate excretion in normal Body Mass Index (BMI) and obese calcium oxalate kidney stone formers.

Will I have to stop taking my current medications?

Yes, you will need to stop taking medications for kidney stone prevention, like thiazides, allopurinol, febuxostat, and citrate preparations, for 14 days before the study starts and during the study. You can restart these medications after the study ends.

What data supports the effectiveness of the treatment Controlled Diet, Dietary Intervention, Nutritional Therapy for kidney stones in obese individuals?

Research suggests that obesity is linked to an increased risk of kidney stones, and dietary changes can influence urinary risk factors for stone formation. A controlled diet and nutritional therapy may help manage these risk factors by reducing the excretion of substances like calcium and oxalate, which contribute to stone formation. ^{1 2 3 4 5}

Is a controlled diet safe for humans?

Research on dietary interventions for kidney stones in obese individuals suggests that following a low-calorie diet is generally safe. However, maintaining long-term dietary changes can be challenging for some people. ^{2 6 7 8 9}

How does the controlled diet treatment for kidney stones in obese individuals differ from other treatments?

The controlled diet treatment focuses on modifying dietary habits to reduce the risk of kidney stones, particularly in obese individuals, by addressing factors like body mass index and fluid intake, unlike other treatments that may involve medication or surgery. This approach is unique because it targets lifestyle changes, such as following a DASH diet (a diet rich in fruits, vegetables, and low-fat dairy), which can help prevent stone formation by managing weight and improving overall nutrition. ^{1 2 10 11 12}

Research Team

Dean G Assimos, MD

Principal Investigator

University of Alabama at Birmingham

Eligibility Criteria

This trial is for adults with normal (BMI ≥ 18.5 to < 25) or obese (BMI ≥ 30 to ≤ 45) who form calcium oxalate kidney stones, can consent, and follow a controlled diet without vigorous exercise. Excluded are those with diabetes, abnormal blood tests, certain kidney diseases, gastrointestinal disorders affecting oxalate transport, recent cancer treatment, pregnancy or breastfeeding women not using birth control.

Inclusion Criteria

No food allergies or intolerance to any of the food in study menus

Willingness to not undertake vigorous exercise during the controlled dietary study

I am willing to stop my kidney stone prevention meds for the study duration.

Exclusion Criteria

I have been diagnosed with primary hyperparathyroidism.

I have high oxalate levels in my urine due to intestinal issues.

Your fasting blood test shows abnormal results for your body's chemical levels.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Controlled Dietary Study

Participants consume a controlled diet for five days, provide urine collections, and undergo blood sampling after ingesting carbon-13 oxalate and sucralose

5 days

Daily visits for urine collection and blood sampling

Follow-up

Participants are monitored for safety and effectiveness after the controlled dietary study

2 weeks

Treatment Details

Interventions

• Controlled Diet

Trial Overview The study investigates how obesity affects the body's processing of oxalate in people prone to calcium oxalate kidney stones. Participants will follow a controlled diet and ingest Carbon-13 Oxalate and Sucralose to track their metabolism and urinary excretion patterns.

Participant Groups

Group I: Controlled Dietary Study Experimental Treatment 2 Interventions

Participants will consume the controlled diet for five days. After one day on the diet, subjects will provide three 24-hour urine collections. On the last dayof the diet, subjects will come in a fasted state to ingest a small amount of carbon-13 oxalate and sucralose, with hourly urine collections and blood samples being taken before and after the ingestion.

Who Is Running the Clinical Trial?

University of Alabama at Birmingham

Lead Sponsor

Trials

1,677

Recruited

2,458,000+

Findings from Research

A 12-week low-calorie diet for obese adults with idiopathic calcium oxalate kidney stones did not lead to a decrease in 24-hour urinary lithogenic parameters, indicating that weight loss alone may not reduce stone risk.

Despite some participants achieving a BMI below 30 kg/m², the study suggests that calcium oxalate stone formation is likely influenced by factors beyond just body weight, highlighting the complexity of this condition.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of a low-calorie diet on 24-hour urinary parameters of obese adults with idiopathic calcium oxalate kidney stones. Danilovic, A., Marchini, GS., Pucci, ND., et al.[2022]

In a study of 112 patients who received dietary recommendations to prevent kidney stones, patients recalled about 67% of the advice given, with better recall for key recommendations like increasing fluid intake and reducing meat consumption.

Patients who received fewer than four dietary recommendations had a higher recall rate (47% recalled all recommendations) compared to those given more than three, suggesting that simplifying dietary advice may improve patient adherence and understanding.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Factors associated with patient recall of individualized dietary recommendations for kidney stone prevention. Penniston, KL., Wertheim, ML., Nakada, SY., et al.[2018]

In a study involving 192,126 participants over 3,259,313 person-years, five modifiable risk factors (body mass index, fluid intake, DASH diet, dietary calcium intake, and sugar-sweetened beverage intake) were found to account for over 50% of kidney stone incidents, highlighting their significant role in prevention.

The most impactful risk factor was lower fluid intake, which had a population attributable fraction of 26.0%, suggesting that increasing fluid consumption could substantially reduce the occurrence of kidney stones in the general population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary and Lifestyle Risk Factors Associated with Incident Kidney Stones in Men and Women. Ferraro, PM., Taylor, EN., Gambaro, G., et al.[2019]

References

1. Netherlands pubmed.ncbi.nlm.nih.gov

Association Between Body Fat Mass and Kidney Stones in US Adults: Analysis of the National Health and Nutrition Examination Survey 2011-2018. [2022]

2. Australia pubmed.ncbi.nlm.nih.gov

Overweight and high-sensitivity C-reactive protein are weakly associated with kidney stone formation in Japanese men. [2014]

3. Germany pubmed.ncbi.nlm.nih.gov

Obesity and urolithiasis: evidence of regional influences. [2018]

4. United States pubmed.ncbi.nlm.nih.gov

Effect of being overweight on stone-forming risk factors. [2022]

5. United States pubmed.ncbi.nlm.nih.gov

Effects of dietary fat on the urinary risk factors of calcium stone disease. [2019]

6. Brazil pubmed.ncbi.nlm.nih.gov

Effect of a low-calorie diet on 24-hour urinary parameters of obese adults with idiopathic calcium oxalate kidney stones. [2022]

7. England pubmed.ncbi.nlm.nih.gov

Factors associated with patient recall of individualized dietary recommendations for kidney stone prevention. [2018]

8. England pubmed.ncbi.nlm.nih.gov

Kidney stone composition in overweight and obese patients: a preliminary report. [2021]

9. United States pubmed.ncbi.nlm.nih.gov

Can obese stone formers follow dietary recommendations? [2019]

10. United States pubmed.ncbi.nlm.nih.gov

Dietary and Lifestyle Risk Factors Associated with Incident Kidney Stones in Men and Women. [2019]

11. Italy pubmed.ncbi.nlm.nih.gov

Obesity rates in renal stone formers from various countries. [2021]

12. Sweden pubmed.ncbi.nlm.nih.gov

Impact of food quantity and quality on the biochemical risk of renal stone formation. [2019]