The experiment included 40 male C57BL/6J mice randomly assigned to four groups of 10: a control group, an untreated glyoxylic acid model group, and model groups given low- or high-dose beer. During a seven-day pretreatment phase, the intervention groups received 3 or 6 mL/kg of commercial beer by oral gavage, while control animals received equal volumes of water. During the following seven days, all model groups received 100 mg/kg glyoxylic acid daily by intraperitoneal injection, and controls received saline. The beer contained 2.9% alcohol by volume and delivered approximately 1.37 or 2.75 mg of ethanol per mouse per day. All 40 randomized animals completed the experiment, and no data points were excluded.

Untreated model mice lost weight from approximately day 6, had lower kidney wet weights and developed pale, shrunken kidneys. Their serum creatinine and blood urea nitrogen concentrations were elevated relative to controls. Beer pretreatment attenuated weight loss and moved kidney weight toward control levels, particularly at the higher dose, while reducing serum creatinine and blood urea nitrogen. These were associations within the mouse experiment rather than evidence that beer treats kidney-stone disease in patients.

Kidney histology showed extensive calcium oxalate crystal deposition, tubular dilation, glomerular atrophy, inflammatory changes and collagen accumulation in untreated model animals. Hematoxylin and eosin staining indicated fewer crystals in both beer groups. Periodic acid–Schiff staining showed less accumulation of material in renal tubules after beer intervention, although glomerular atrophy persisted. Masson’s trichrome staining showed less interstitial collagen deposition in the beer groups. Researchers also used a study-specific composite renal injury score from zero to five that incorporated crystal number, tubular obstruction, glomerular atrophy, inflammation, fibrosis and edema; histological and other image-based endpoints were designated secondary or exploratory.

Beer intervention was associated with lower immunohistochemical expression of CD44 and osteopontin in renal tubular tissue. Quantitative PCR also showed lower CD44 and Kim-1 messenger RNA in the beer groups, with the strongest attenuation generally occurring at the higher dose. CD44 and osteopontin are associated with crystal adhesion, while Kim-1 is a marker of tubular injury. The experiment did not establish that changes in these molecules directly caused the lower crystal burden, and the reduced expression could instead have reflected fewer crystals and less secondary tissue damage.

Inflammatory and antioxidant measurements also varied by dose. Untreated model mice had increased tumor necrosis factor-alpha and interleukin-1 beta messenger RNA and reduced catalase and superoxide dismutase activities. Beer partially preserved antioxidant enzyme activities, but only the high-dose group had a statistically significant reduction in tumor necrosis factor-alpha and significant recovery of catalase and superoxide dismutase activity. The change in interleukin-1 beta did not reach statistical significance. Because catalase and superoxide dismutase measure enzyme activity rather than oxidative damage directly, the evidence for attenuation of oxidative stress was indirect.

Urinary oxalate and calcium concentrations were lower in beer-treated mice than in untreated model animals. The authors considered an ethanol-driven diuretic explanation unlikely because the gavage volumes represented only about 1.2% to 4% of reported daily fluid intake, the ethanol doses were low and daily water consumption declined rather than increased during induction. Nevertheless, 24-hour urine volume and urine osmolality were not measured, nor were urinary citrate, magnesium or uric acid. The results therefore concern concentrations rather than 24-hour solute excretion, and a dilution effect cannot be excluded. The experiment also lacked non-alcoholic beer and ethanol-matched control groups, and the beer was not chemically characterized, so its effects could not be assigned to ethanol, hops-derived polyphenols or other constituents.

The clinical component was a single-centre retrospective case series involving 281 men and 134 women, with a mean age of 55.0 ± 14.2 years. Calcium oxalate monohydrate was detected in 79.0% of the 415 specimens, carbonate apatite in 54.9% and calcium oxalate dihydrate in 41.0%; mixed compositions were common, and uric acid was detected in 9.2%. The male-to-female ratio among included cases was 2.1:1. Because the study lacked a source-population denominator, these findings describe only the composition and age and sex distribution of submitted specimens and cannot establish incidence, prevalence or relative risk. Beer consumption was not recorded, so the clinical data neither support nor contradict the experimental observations.

The authors said the results should not be interpreted as a recommendation to consume beer for kidney-stone prevention. Beer carries a purine load that can increase uric acid, and excessive alcohol has established harms. Their proposed alternative was to test whether a purified, standardized, purine-free and non-alcoholic hops-derived polyphenol preparation could reproduce beneficial effects, but that remains a hypothesis. The animal model represented acute glyoxylic acid-induced crystallization rather than the full complexity of chronic human stone disease, and the study cannot establish which constituent or pathway produced the observed effects.

Subject of Research: Effects of dietary beer pretreatment on glyoxylic acid-induced calcium oxalate nephrolithiasis in mice

Article Title: Dietary beer ameliorates glyoxylic acid-induced calcium oxalate nephrolithiasis in mice

Article References: Yang, Y., Deng, X., Zhang, J., Dai, Y., Wu, X., & Liang, W. (2026). Dietary beer ameliorates glyoxylic acid-induced calcium oxalate nephrolithiasis in mice. Frontiers in Nutrition, 13, Article 1963460. https://doi.org/10.3389/fnut.2026.1963460

Image Credits: AI Generated

DOI: 10.3389/fnut.2026.1963460

Keywords: calcium oxalate, kidney stones, beer, mouse model, urolithiasis, renal injury, crystal adhesion, inflammation, oxidative stress, clinical case series, Dietary, ameliorates