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ORLANDO, Fla. — Certain dietary supplements inhibit the formation, growth, and aggregation of calcium oxalate kidney stones and may ultimately aid in prevention, according to new research presented this week at NUTRITION 2025, the annual meeting of the American Society for Nutrition.

“We have searched for many new approaches with a hope of reducing kidney stone disease and its recurrence,” Visith Thongboonkerd, MD, Siriraj Hospital, Mahidol University in Bangkok, Thailand, told Medscape Medical News.

Recent work by Thongboonkerd and colleagues found that while normal urinary proteins (proteome) inhibit calcium oxalate crystallization, growth, and aggregation, the urinary proteome of individuals who form kidney stones actually promotes these calcium oxalate crystal parameters via oxidative modifications.

The new findings, presented at NUTRITION 2025, represent the team’s efforts to investigate whether dietary supplements could modulate these oxidative modifications, potentially preventing stones from forming.

Inhibitory Effects Revealed

Using crystallization, growth, and aggregation assays, the team compared the modulatory effects of caffeine, epigallocatechin-3-gallate (EGCG), N-acetylcysteine (NAC), resveratrol, and trigonelline (at 1, 10, and 100 μM — ie, within their physiologic range in urine) on calcium oxalate crystals.

They found that the supplements had diverse effects: Caffeine inhibited crystal formation, EGCG inhibited crystal formation and growth, NAC inhibited crystal aggregation, resveratrol inhibited crystal growth, and trigonelline inhibited crystal growth and aggregation.

Notably, however, resveratrol also promoted crystal aggregation and thus served as a dual modulator, acting as an inhibitor and promoter at different steps of stone formation.

Further analyses revealed that EGCG was the most potent inhibitor against calcium oxalate crystal formation, whereas resveratrol was the most potent inhibitor against calcium oxalate crystal growth. NAC was the only inhibitor against calcium oxalate crystal aggregation.

The findings support roles of these supplements in kidney stone disease prevention, the authors suggested. “It will take a while before we can draw a clear conclusion that prescribing these supplements would really be beneficial to kidney stone patients, without any harms,” Thongboonkerd acknowledged. Next steps would include validating the in vitro findings in clinical settings.

This study received funding from the National Research Council of Thailand (NRCT): High-Potential Research Team Grant Program (N42A660625). Thongboonkerd disclosed having no conflicts of interest.

Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.