Nephrolithiasis, or kidney stone disease, affects about 10% of the global population and significantly burdens healthcare systems due to its recurrent nature and management costs. Recent research emphasizes dietary modifications and natural supplements for managing this condition. Grape Seed Polyphenolic Extracts (GSPEs) show promise as a non-pharmacological intervention due to their anti-inflammatory and antioxidant properties, which may modulate urinary pH a key factor in stone formation. This systematic review and meta-analysis will evaluate GSPEs effectiveness in altering urinary pH and reducing stone recurrence.

Following PRISMA guidelines, databases such as PubMed, Embase, Cochrane Library, and Web of Science were searched up to December 2023, identifying 15 initial studies. Seven studies met the inclusion criteria, requiring detailed pre- and post-intervention urinary pH measurements. Selection process is shown in the accompanying PRISMA flow diagram. Two reviewers independently conducted data extraction and assessed methodological quality using the Cochrane Risk of Bias tool and the Newcastle-Ottawa Scale for a thorough evaluation.

The seven included studies, involving a total of 1,200 participants, demonstrated that GSPE supplementation significantly increased urinary pH, especially benefiting patients with uric acid and calcium oxalate stones. Moderate heterogeneity (I² = 59%) was observed and explored through sensitivity analyses, confirming the stability of the results across varying study conditions and populations.

The findings indicate that Grape Seed Polyphenolic Extracts (GSPEs) can effectively modulate urinary pH, potentially reducing kidney stone recurrence in nephrolithiasis patients. As a natural, less invasive option, GSPEs complement traditional treatments, reflecting a trend toward complementary medicine. Future research should emphasize long-term outcomes, optimal dosing, and integration into disease management programs to enhance patient care.