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

82 Participants Needed

Trial Summary

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.

What data supports the effectiveness of the treatment Dietary Oxalate for kidney stone prevention?

Research suggests that a diet with normal calcium intake and reduced animal protein, salt, and oxalate can positively affect urine chemistry, which may help prevent kidney stones. However, the specific role of oxalate restriction alone in preventing stones is still debated. ^{1 2 3 4 5}

Is dietary oxalate intake safe for humans?

Research suggests that consuming foods high in oxalate can increase urinary oxalate levels, which may contribute to kidney stone formation. However, increasing dietary calcium can help reduce this risk by binding oxalate in the gut, indicating that managing oxalate intake with adequate calcium is generally safe. ^{6 7 8 9 10}

How does the treatment of dietary oxalate intake differ from other treatments for kidney stone prevention?

The treatment of dietary oxalate intake for kidney stone prevention is unique because it focuses on reducing the consumption of oxalate-rich foods, which can contribute to the formation of calcium oxalate stones. Unlike other treatments that may involve medication or supplements, this approach emphasizes dietary changes, such as increasing calcium intake to bind oxalate in the gut and avoiding foods like spinach, tea, and coffee that are high in oxalate. ^{7 8 11 12 13}

What is the purpose of this trial?

The purpose of this study is to evaluate mitochondrial function in white blood cells and platelets from healthy individuals following dietary oxalate intake.

Research Team

Tanecia Mitchell, PhD

Principal Investigator

University of Alabama at Birmingham

Eligibility Criteria

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

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

Treatment Details

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.

Participant Groups

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+

Findings from Research

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 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]

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]

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]

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]

References

1. England pubmed.ncbi.nlm.nih.gov

Effect of dietary intake on urinary oxalate excretion in calcium renal stone formers. [2019]

2. Switzerland pubmed.ncbi.nlm.nih.gov

Effect of dietary intake on urinary oxalate excretion in calcium oxalate stone formers in their forties. [2018]

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

Diet to reduce mild hyperoxaluria in patients with idiopathic calcium oxalate stone formation: a pilot study. [2022]

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

Effects of an oxalate load on urinary oxalate excretion in calcium stone formers. [2019]

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

Prospects for dietary therapy of recurrent nephrolithiasis. [2014]

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

Dietary factors and kidney stone formation. [2013]

7. Poland pubmed.ncbi.nlm.nih.gov

Tea and coffee as the main sources of oxalate in diets of patients with kidney oxalate stones. [2015]

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

Effect of dietary oxalate and calcium on urinary oxalate and risk of formation of calcium oxalate kidney stones. [2022]

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

Dietary oxalate loads and renal oxalate handling. [2013]

10. England pubmed.ncbi.nlm.nih.gov

High-calcium intake abolishes hyperoxaluria and reduces urinary crystallization during a 20-fold normal oxalate load in humans. [2019]

11. Netherlands pubmed.ncbi.nlm.nih.gov

Idiopathic calcium oxalate urolithiasis: risk factors and conservative treatment. [2016]

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

Dietary oxalate and kidney stone formation. [2023]

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

Oxalate intake and the risk for nephrolithiasis. [2022]