The role of citrus juice in reducing calcium kidney stone risk: a systematic review and meta-analysis of clinical trials

Urolithiasis affects 10–14% of individuals in developed countries, with a rising prevalence of calcium oxalate stones. Citrus juices are rich in citrate—a natural inhibitor of calcium stone formation. This systematic review and meta-analysis assess the impact of citrus juices on urinary parameters related to kidney stone formation. PubMed and Cochrane CENTRAL were systematically searched from inception till October 2024, while following PRISMA guidelines. All clinical trials evaluating the effects of citrus juice consumption on urinary citrate, calcium, oxalate, and pH levels were included in this review. Statistical analyses were performed on Review Manager and effect sizes were pooled as mean differences (MD) with 95% confidence intervals (CI) using a random effects model. Statistical heterogeneity was assessed using I2 statistics and I < 50% was deemed acceptable. The risk of bias was assessed using the Cochrane RoB2 Tool. The systematic review included 16 studies (552 patients), with 3 pooled for meta-analysis (240 patients). Citrus juice consumption was associated with trends towards increased urinary citrate levels (MD = 68.82 [-13.93,151.57]; p < 0.10) among patients on juice therapy which gained statistical significance on leave-one-out analysis (MD = 101.11 [55.2,147.02]; P < 0.0001). Changes in urinary calcium, and oxalate levels were non-significant. Urinary pH exhibited no significant changes, although qualitative synthesis suggested potential benefits for kidney stone prevention. Citrus juices may enhance urinary citrate levels helping to prevent calcium stone formation. This suggests their role as a safe, natural adjunct to pharmacological treatments. Further trials are warranted to ascertain the benefits of citrus juices in mitigating the risk of kidney stone formation.