Dietary Oxalate Intake for Kidney Stone Prevention

Overseen By Tanecia Mitchell, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Alabama at Birmingham

Must not be taking: Medications, Supplements

Disqualifiers: Pregnancy, Kidney stones, Tobacco, others

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

Compensation: Varies

Number of Visits: 2

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how different diets containing oxalate, found in foods like spinach and kale, affect blood cells. Researchers aim to understand how these diets might help prevent kidney stones. Participants will follow a meal plan for a few days and consume a special smoothie or drink on the last day. The study seeks healthy adults who do not smoke, have a body mass index (BMI) between 19 and 27, and have no history of kidney stones. As an unphased trial, participants contribute to valuable research that may lead to new dietary recommendations for kidney stone prevention.

Will I have to stop taking my current medications?

Yes, you will need to stop taking your current medications or dietary supplements to participate in this trial.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that most people can consume foods with oxalate without issues, though there is a small risk of kidney stones. Studies indicate a slightly higher chance of developing kidney stones from oxalate, with a relative risk of 1.21 for men and 1.22 for older women. This means the risk is marginally higher but not significant for most people.

Additionally, research found that for every 100 mg of oxalate consumed, the body excretes 2.7 mg through urine. This suggests that the body can handle moderate amounts of oxalate without major problems. Overall, consuming foods with oxalate is considered safe for most people when eaten in normal amounts. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores how dietary oxalate intake can be managed to prevent kidney stones, offering a potentially new approach compared to standard treatments like medication or surgery. Unlike conventional options that typically manage symptoms or remove existing stones, this trial focuses on dietary modifications to prevent stone formation in the first place. By testing various dietary components like sodium oxalate drinks and smoothies made from kale and spinach, researchers aim to understand the impact of different oxalate sources on stone prevention. This could lead to more personalized and proactive dietary strategies for people prone to kidney stones.

What evidence suggests that this trial's treatments could be effective for kidney stone prevention?

Research has shown that diet can affect kidney stone formation. Consuming foods high in oxalate, a natural compound, is linked to a higher risk of developing calcium oxalate stones, the most common type of kidney stone. This trial will explore various dietary interventions, including smoothies and meals, to assess their impact on oxalate levels and kidney stone risk. Some studies suggest that reducing oxalate intake might lower the risk of these stones, but results can vary among individuals. One study found that people with kidney stones might absorb more oxalate from their gut, potentially leading to stone formation. Overall, adjusting oxalate intake is considered a possible strategy for managing kidney stones, although individual responses can differ. ^{1 4 6 7 8}

Who Is on the Research Team?

Tanecia Mitchell, PhD

Principal Investigator

University of Alabama at Birmingham

Are You a Good Fit for This Trial?

This trial is for mentally competent adults aged 18-70, with a BMI of 19-27, who don't use tobacco or vigorous exercise during the study. They must understand English consent forms and have normal blood tests. It's not for pregnant individuals, those on medications/supplements, with medical problems or history of kidney stones.

Inclusion Criteria

Willingness to abstain from vigorous exercise during study period

Non-tobacco users

I can read and understand English and am mentally capable of making my own decisions.

Exclusion Criteria

I have a condition that affects how my body absorbs or gets rid of oxalate.

I am able to understand and consent to the study on my own.

I am currently taking medications or dietary supplements.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Dietary Intervention

Participants consume prepared meals for 3 to 5 days, with fasting on the final day, followed by consumption of a specific drink and breakfast meal

3-5 days

1 visit (in-person) on the final day

Assessment

Cellular bioenergetics measured in isolated monocytes before and after dietary intervention

5 hours

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after dietary intervention

1 week

What Are the Treatments Tested in This Trial?

Interventions

• Dietary Oxalate

Trial Overview

The study is testing how different drinks (kale smoothie, spinach smoothie, sodium oxalate drink) affect immune cell function in healthy people by looking at mitochondrial function in white blood cells and platelets after consuming dietary oxalate.

How Is the Trial Designed?

Group I: 5d Diet+Spinach Smoothie+Breakfast Experimental Treatment 2 Interventions

5 days of prepared meals with fasting on the final day. On final day, participants will return to the study site and drink a prepared blended spinach smoothie and be provided a breakfast meal.

Group II: 3d Diet+V Spinach Smoothie+Breakfast Experimental Treatment 2 Interventions

3 days of prepared meals with fasting on the final day. On final day, participants will return to the study site and drink a prepared blended spinach smoothie with varying amounts of spinach and be provided a breakfast meal.

Group III: 3d Diet+Spinach Smoothie+Breakfast w/ 24 Hr Urine Experimental Treatment 2 Interventions

3 days of prepared meals with fasting on the final day. On final day, participants will return to the study site and drink a blended spinach smoothie and be provided a breakfast meal.

Group IV: 3d Diet+Spinach Smoothie+Breakfast Experimental Treatment 2 Interventions

3 days of prepared meals with fasting on the final day. On final day, participants will return to study site and drink a prepared blended spinach smoothie and be provided a breakfast meal.

Group V: 3d Diet+Sodium Oxalate Drink+Breakfast Experimental Treatment 2 Interventions

3 days of prepared meals with fasting on the final day. On final day, participants will return to the study site and drink a prepared sodium oxalate drink and be provided a breakfast meal.

Group VI: 3d Diet+Kale Smoothie+Breakfast Experimental Treatment 2 Interventions

3 days of prepared meals with fasting on the final day. On the final day, participants will return to the study site and drink a prepared kale smoothie and be provided a breakfast meal.

Group VII: 3d Diet+Breakfast Experimental Treatment 1 Intervention

3 days of prepared meals with fasting on the final day. On final day, participants will return to the study site and be provided a breakfast meal.

Group VIII: 3d Diet+Blended Smoothie+Breakfast Experimental Treatment 2 Interventions

3 days of prepared meals with fasting on the final day. On final day, participants will return to the study site and drink a prepared blended smoothie and be provided a breakfast meal.

Who Is Running the Clinical Trial?

University of Alabama at Birmingham

Lead Sponsor

Trials

1,677

Recruited

2,458,000+

Published Research Related to This Trial

Restricting dietary oxalate intake can help reduce the risk of calcium oxalate kidney stones, especially in individuals who absorb oxalate at high rates; only a few specific foods like spinach and chocolate significantly increase urinary oxalate excretion.

Increasing calcium intake may help lower urinary oxalate levels by binding oxalate in the gut, suggesting that a balanced approach to calcium and oxalate consumption is important for effective dietary management of kidney stone risk.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of dietary oxalate and calcium on urinary oxalate and risk of formation of calcium oxalate kidney stones. Massey, LK., Roman-Smith, H., Sutton, RA.[2022]

Dietary counseling is crucial for preventing kidney stones, particularly calcium oxalate stones, which are the most common type, and should focus on modifiable dietary factors.

Individuals with a history of calcium-containing kidney stones should maintain adequate fluid intake (at least 2 liters of urine per day) and not restrict calcium intake, as a minimum of 800 mg/day is recommended to prevent negative health effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary factors and kidney stone formation. Curhan, GC., Curhan, SG.[2013]

In a study of 60 calcium renal-stone formers, higher dietary intake of carbohydrates and fats was positively correlated with increased urinary oxalate excretion, suggesting these nutrients may influence stone formation.

Conversely, calcium intake was found to be inversely correlated with urinary oxalate excretion, indicating that higher calcium consumption may help reduce oxalate levels in urine, while protein intake showed minimal impact.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of dietary intake on urinary oxalate excretion in calcium renal stone formers. Masai, M., Ito, H., Kotake, T.[2019]

A proposed randomized controlled trial aims to test whether dietary changes, particularly increasing calcium intake to 1,200 mg/day while reducing animal protein, salt, and oxalate, can effectively prevent recurrent kidney stones, building on previous successful trials.

The article highlights the need for further research on dietary oxalate's role in stone formation and suggests that weight loss through low-fat or low-calorie diets may also help reduce kidney stone recurrence.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prospects for dietary therapy of recurrent nephrolithiasis. Goldfarb, DS.[2014]

A normal-calcium, low-animal protein, low-salt diet significantly reduced oxalate excretion in patients with idiopathic calcium oxalate nephrolithiasis, decreasing mean oxaluria from 50.2 to 35.5 mg/d over 3 months.

In comparison, a traditional low-oxalate diet only reduced oxaluria from 45.9 to 40.2 mg/d, indicating that the new diet may be more effective in managing hyperoxaluria.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Diet to reduce mild hyperoxaluria in patients with idiopathic calcium oxalate stone formation: a pilot study. Nouvenne, A., Meschi, T., Guerra, A., et al.[2022]

Citations

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