Evaluation of the Online Information Landscape and Oxalate Content of Purportedly Antilithogenic Ingredients

The popularity of over-the-counter (OTC) supplements has led to their increased utilization among patients for kidney stone management.^9,11 However, a more thorough understanding of the ingredients in OTC supplements marketed to treat nephrolithiasis is needed. These supplements are often bought online, given the substantial increase in online information and shopping in the past decade. Therefore, it is also important to evaluate public interest and the reliability of online information for these purportedly antilithogenic ingredients.

The best-selling supplements marketed to treat kidney stones on Amazon.com were compiled to identify the most common ingredients. A literature review was completed to assess clinical support for common ingredients. BuzzSumo software was used to quantify online engagement with articles on each ingredient, as well as the overall topic of alternative treatments for kidney stones. Articles were evaluated for reliability using the DISCERN tool. Ion chromatography coupled with mass spectrometry was used to assess oxalate content in the most commonly found ingredients in OTC kidney stone supplements.

Evidence for stone prevention for the most common supplement ingredients was limited or lacking altogether, based on literature review. Public interest in supplement ingredients was between 2-fold and 10-fold greater than potassium citrate, a commonly prescribed stone prevention medication. Online articles for all ingredients showed poor reliability. Oxalate analysis showed chanca piedra, turmeric, and cinnamon contained 8.2, 8.6, and 14.0 mg oxalate per dose. These findings suggest that patients and providers should exercise caution while using OTC supplements for stone management, and that additional investigations of the composition and clinical efficacy of these ingredients are needed.