Written by Joyce Smith, BS. A three day supplementation with green tea extract significantly reduced the symptoms of urinary tract infections in the participating premenopausal women compared to those in the control group.
Urinary tract infections (UTIs) are more prevalent in women than men 1 and are particularly common in healthy premenopausal and non-pregnant women. Escherichia coli (E.coli), the bacteria responsible for 75–95% of uncomplicated UTIs, has become resistant to trimethoprim-sulfamethoxazole (co-trimoxazole), an inexpensive, traditional, well tolerated, and effective antibiotic of choice for UTIs 2. Studies have shown antimicrobial effects of green tea catechins against E. coli as well as synergistic effects between catechins and antibiotics such as co-trimoxazole against E. coli. Consequently, antibacterial herbs have garnered attention as an adjunctive treatment 3.
Green tea from the non-fermented leaves of Camellia sinensis is a popular Asian beverage that exhibits antiinflammatory, antiarthritic, antibacterial, antiangiogenic, antioxidative, antiviral, and neuroprotective effects 4 Of the major green tea catechins, EGC and IGCG are present in the greatest concentrations and have the greatest antimicrobial effects 5,6. The aim of this study was to evaluate the efficacy of green tea as an adjunctive therapy to standard antimicrobial treatment in women with acute uncomplicated cystitis.
This randomized, blinded, placebo-controlled trial 7 involved healthy premenopausal, non-pregnant Iranian women, ages 18-50, with acute uncomplicated cystitis. After urine collection, women were assigned either a 3-day, once daily supplementation of four 500 mg green tea extract capsules or a starch placebo before bedtime. In addition, all participants received two 480 mg tablets of co-trimoxazole twice daily for 3 days. Each gram of green tea contained a total phenolic content of approximately 283 mg and 65 mg of epigallocatechin (EGC). Both groups had their urine tested on the fourth day.
Results: Among the 107 eligible women patients, 70 completed the trial. Women in the green tea group showed a statistically significant decrease in the prevalence of cystitis symptoms at each time point (recorded daily). The presence of symptoms was as follows:
- At baseline: Green tea 68%; placebo 75% P<0.009
- After 1 day Green tea 61%; placebo 74% P<0.001
- After 2 days Green tea 34%; placebo 67% P< 0.0001
- After 3 days Green tea 2%; placebo 63% P<0.0001
Supplementing with green tea extract resulted in a statistically significant improvement in the urinalysis in terms of color, bacteria, and white blood cells. No patients, in either group, had a recurrence of their UTI after 2 weeks. After 4 weeks, one in the green tea group had a recurrence and after 6 weeks, two in the co-trimoxazole only group had a recurrence. The percentage of the patients who had recurrent symptoms six weeks after the enrollment was lower in the green tea group when compared to the placebo group
In this study, green tea extract was given in the evening and as a bolus (all four capsules at once) allowing for better bladder retention overnight 8, since more than 90% of the urinary EGC is excreted in the first 8 hours of administration 9. Therefore, a one-time evening dose before bed would theoretically enhance its effectiveness, providing urination did not occur until morning. Urine cultures to identify uropathogens causing UTIs and testing to determine their potential sensitivity to co-trimoxazole was not done. Larger clinical trials with green tea as the primary supplement are warranted.
Source: Kheirabadi, Zahra, Mitra Mehrabani, Farhad Sarafzadeh, Fatemeh Dabaghzadeh, and Negar Ahmadinia. “Green tea as an adjunctive therapy for treatment of acute uncomplicated cystitis in women: A randomized clinical trial.” Complementary therapies in clinical practice 34 (2019): 13-16.
© 2018 Elsevier Ltd. All rights reserved.
Posted April 29, 2019.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
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- Gupta K, Hooton TM, Stamm WE. Increasing antimicrobial resistance and the management of uncomplicated community-acquired urinary tract infections. Ann Intern Med. 2001;135(1):41-50.
- Noormandi A, Dabaghzadeh F. Effects of green tea on Escherichia coli as a uropathogen. J Tradit Complement Med. 2015;5(1):15-20.
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- Lee MJ, Maliakal P, Chen L, et al. Pharmacokinetics of tea catechins after ingestion of green tea and (-)-epigallocatechin-3-gallate by humans: formation of different metabolites and individual variability. Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology. 2002;11(10 Pt 1):1025-1032.
- Kheirabadi Z, Mehrabani M, Sarafzadeh F, Dabaghzadeh F, Ahmadinia N. Green tea as an adjunctive therapy for treatment of acute uncomplicated cystitis in women: A randomized clinical trial. Complement Ther Clin Pract. 2019;34:13-16.
- S.-H. Song, K.S. Kim, Antibiotic prophylaxis in pediatric urology, Indian J. Urol 24 (2) (2008) 145–149
- M.-J. Lee, P. Maliakal, L. Chen, X. Meng, F.Y. Bondoc, S. Prabhu, G. Lambert, S. Mohr, C.S. Yang, Pharmacokinetics of tea catechins after ingestion of green tea and (-)-epigallocatechin- 3-gallate by humans: formation of different metabolites and individual variability, Cancer Epidemiol. Biomark. Prev. 11 (10) (2002) 1025–1032.
