Department of Urology, University Stone Center, University Hospital Bonn, 53127 Bonn, Germany.
Nutrients. 2021 Dec 11;13(12):4434. doi: 10.3390/nu13124434.
Copious fluid intake is the most essential nutritional measure in the treatment of urolithiasis, and is suggested to be a protective factor in the primary prevention of urinary stone formation. Although the intake of black tea contributes to daily fluid intake, the high oxalate content could outweigh the beneficial effect of urine dilution. The present study investigated the effect of black tea consumption on urinary risk factors for kidney stone formation. Ten healthy men received a standardized diet for a period of ten days. Subjects consumed 1.5 L/day of fruit tea (0 mg/day oxalate) during the 5-day control phase, which was replaced by 1.5 L/day of black tea (86 mg/day oxalate) during the 5-day test phase. Fractional and 24-h urines were obtained. The intake of black tea did not significantly alter 24-h urinary oxalate excretion. Urinary citrate, an important inhibitor of calcium stone formation, increased significantly, while the relative supersaturation of calcium oxalate, uric acid, and struvite remained unchanged. No significantly increased risk for kidney stone formation could be derived from the ingestion of black tea in normal subjects. Further research is needed to evaluate the impact of black tea consumption in kidney stone patients with intestinal hyperabsorption of oxalate.
大量饮水是治疗尿路结石最重要的营养措施，并且被建议是预防尿路结石形成的保护因素。虽然红茶的摄入有助于日常液体摄入，但高草酸含量可能超过尿液稀释的有益作用。本研究调查了红茶消费对肾结石形成的尿危险因素的影响。十名健康男性在十天的时间内接受了标准化饮食。在 5 天的对照期内，受试者每天饮用 1.5 升果茶（草酸 0 毫克/天），在 5 天的试验期内，用 1.5 升红茶（草酸 86 毫克/天）代替。收集了部分和 24 小时尿液。红茶的摄入并没有显著改变 24 小时尿草酸排泄量。尿枸橼酸盐，一种重要的钙结石形成抑制剂，显著增加，而钙草酸、尿酸和鸟粪石的相对过饱和度保持不变。正常受试者摄入红茶不会导致肾结石形成的风险显著增加。需要进一步研究来评估在肠道草酸过度吸收的肾结石患者中饮用红茶的影响。
