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Effect of Over-the-counter Dietary Supplements on Kidney Stone Risk

University of Wisconsin (UW) logo

University of Wisconsin (UW)

Status

Completed

Conditions

Hyperoxaluria

Treatments

Dietary Supplement: Milk thistle
Dietary Supplement: Green tea extract
Dietary Supplement: Bilberry
Dietary Supplement: Turmeric
Dietary Supplement: Aloe vera
Dietary Supplement: Aloe vera with cactus
Dietary Supplement: Cranberry
Dietary Supplement: Cinnamon

Study type

Interventional

Funder types

Other

Identifiers

NCT02404701
2015-0076

Details and patient eligibility

About

The purpose of this study is to ascertain whether certain supplements promote excessive urinary oxalate excretion and increase the risk for calcium oxalate kidney stones. Supplements that enhance urinary oxalate excretion, as a result of their oxalate concentration or from some other mechanism (e.g., providing substrate for oxalate biosynthesis) will be identified by the investigators.

Full description

The investigators hypothesize that certain over-the-counter dietary supplements will increase urinary excretion of oxalate as measured in 24-h urine collections. The investigators further hypothesize that the concentration of oxalate in dietary supplements may not be associated with urinary oxalate excretion, suggesting that other nutritional components of the supplements may be exerting an influence over oxalate biosynthesis, oxalate absorption in the gastrointestinal tract, and/or renal oxalate handling. These other factors include the form of oxalate in the supplement (water- vs. non water-soluble) and the supplement's concentration of ascorbic acid.

Enrollment

45 patients

Sex

All

Ages

18+ years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

  • At least 18 years of age, no prior personal history of kidney stones

Exclusion criteria

  • Personal history of kidney stones (by subjects' report); known allergy to any of the dietary supplements to be used in the study (by subjects' report); short bowel; active ulcerative colitis or irritable bowel disease; Crohns or Celiac disease; renal tubular acidosis; current use of topiramate or other carbonic anhydrase inhibitor, steroids, allopurinol, thiazide diuretics, or supplemental ascorbic acid >250 mg/day.

Trial design

Primary purpose

Basic Science

Allocation

Randomized

Interventional model

Single Group Assignment

Masking

None (Open label)

45 participants in 8 patient groups

Aloe vera with cactus
Experimental group
Description:
1 capsule (500 mg), 2 times/day
Treatment:
Dietary Supplement: Aloe vera with cactus
Cranberry
Experimental group
Description:
3 capsules (810 mg), 2 times/day
Treatment:
Dietary Supplement: Cranberry
Green tea extract
Experimental group
Description:
2 capsules (630 mg), 2 times/day
Treatment:
Dietary Supplement: Green tea extract
Bilberry
Experimental group
Description:
1 softgel (1000 mg), 2 times/day
Treatment:
Dietary Supplement: Bilberry
Cinnamon
Experimental group
Description:
1 capsule (500 mg), 2 times/day
Treatment:
Dietary Supplement: Cinnamon
Milk thistle
Experimental group
Description:
1 capsule (250 mg), 3 times/day
Treatment:
Dietary Supplement: Milk thistle
Turmeric
Experimental group
Description:
1 capsule (450 mg turmeric + 50 mg turmeric extract), 1 time/day
Treatment:
Dietary Supplement: Turmeric
Aloe vera
Experimental group
Description:
1 capsule (470 mg), 2 times/day
Treatment:
Dietary Supplement: Aloe vera

Trial contacts and locations

1

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Data sourced from clinicaltrials.gov

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