Buyer Beware: Evidence-Based Evaluation of Dietary Supplements for Nephrolithiasis

Abstract

Introduction: Numerous dietary supplements claiming to treat or prevent kidney stones have recently been brought to the market. However, the evidence for these claims is not clear. This study assesses the scientific evidence supporting dietary supplements for the treatment and prevention of urinary stone disease. Materials and Methods: Two online marketplaces (Amazon and Google) were queried for dietary supplements available without a prescription to treat, alleviate, or prevent stone disease. Product labels were reviewed to compile stone-related claims and active ingredients. The 30-day cost of treatment and consumer star rating were assessed. MEDLINE, Web of Science, and Google Scholar were queried with labeled ingredients to assess the scientific evidence from published and lay sources. Results: A total of 27 dietary supplements containing 56 ingredients were analyzed. Supplements made a variety of claims, including dissolving stones (12 products, 44%), preventing stone formation (7 products, 26%), and reducing stone symptoms (6 products, 22%). Mean 30-day cost was $32 (range $4-$189). All products were rated highly by consumers (mean 4.2 of 5 stars). Of the 56 ingredients, 9 (16%) had any published studies for use in stone disease, and 5 (9%) had exclusively studies supporting their use. Eighteen scientific publications about the ingredients were identified, of which six showed mixed or no benefit in stone disease. Overall, 18 (67%) supplements contained ingredients with conflicting or absent evidence of benefit. No association was found between product cost or rating and products containing ingredients supported by human or animal studies (p > 0.05). Conclusions: Two-thirds of dietary supplements claiming to treat or prevent kidney stones contain ingredients with conflicting or no scientific evidence to support their claims. Clinicians should counsel stone formers that the effects of most supplements are unknown or unstudied in humans, and that the absence of evidence does not imply absence of potential harm.

Evidence‐based quality and accuracy of YouTube videos about nephrolithiasis

“…Moreover, there are currently no safeguards to prevent dissemination of misinformation within the comments sections of these otherwise higher‐quality videos. By contrast, videos produced by general wellness and alternative medicine channels had lower DISCERN scores, contained more inaccurate claims, and frequently promoted non‐evidence‐based therapies, such as dietary supplements with limited scientific evidence [27]. As such, clinicians should direct interested patients to videos vetted by academic institutions, not only during in‐person encounters, but also through digital interactions, including social media posts, online communications, and telehealth visits.…”

Dietary Supplements—For Whom? The Current State of Knowledge about the Health Effects of Selected Supplement Use

“…Therefore, dietary supplement packaging may not contain information such as "for cancer prevention" or "for reducing cholesterol". However, although such requirements have long been in food legislation, the practice of portraying dietary supplements as products that quickly alleviate the symptoms of numerous health conditions, both by labelling and advertising methods, is relatively common [143,[150][151][152]. Unsurprisingly, the public often finds it difficult to differentiate between supplements and drugs [5,12] and uses the former to treat various medical conditions [128,153,154].…”

Kidney Stone Prevention: Is There a Role for Complementary and Alternative Medicine?

“…One reason for the use of CAM in the kidney stone population is the difficulty in maintaining dietary changes, the side effect profiles of medications, the low cost, and a belief in the safety of CAM preparations [ 4 ]. Koo et al reported that about two-thirds of dietary supplements used to treat or prevent kidney stones have conflicting or insufficient scientific evidence to support their claims [ 8 ]. In other words, for the majority of ingredients, there are inadequate or absent data to formulate any evidence-based recommendations ( Figure 1 ).…”