Green Tea as Anti-Diabetic: Mechanisms, Epidemiological Evidence, and Clinical Potential
DOI:
https://doi.org/10.54361/LJMR.20.2.64Keywords:
Camellia sinensis, EGCG, GLUT4, Insulin Resistance, α-glucosidase, Gut Microbiota, Type 2 Diabetes MellitusAbstract
Diabetes mellitus (DM) has reached epidemic proportions globally, necessitating the exploration of safe, cost-effective adjunctive therapies. Green tea (Camellia sinensis), particularly epigallocatechin-3-gallate (EGCG) and tea polysaccharides (TPS), has demonstrated significant antidiabetic potential across numerous experimental and clinical settings. This paper provides a comprehensive review of the multifaceted mechanisms through which green tea manages hyperglycemia. These include the potent inhibition of carbohydrate-digesting enzymes alpha-amylase and α-glucosidase, the enhancement of insulin sensitivity, and the protection of pancreatic β-cells from oxidative stress and inflammatory cytokine-induced damage. Some evidence suggests that green tea consumption effectively improves fasting blood glucose (FBG), glycated haemoglobin (HbA1c), and lipid profiles. While bioavailability and clinical inconsistencies remain challenges due to genetic polymorphisms and microbiota variations, green tea is generally considered safe for long-term consumption. In conclusion, green tea stands as a premier bio-functional beverage for the prevention and management of type 2 diabetes and its secondary complications. Future research should prioritize advanced delivery systems, such as nano-encapsulation, to maximise therapeutic outcomes.
Downloads
References
1. Alanazi BS, Alrezehi MS, Alnakhli AH. Green tea's antioxidant properties protect the pancreas in diabetics: An experimental study. Medical Science 2022, 26, ms202e2315.
2. Ansari P, Hannan JM, Choudhury ST, Islam SS, Talukder A, Seidel V, Abdel-Wahab YH. Antidiabetic actions of ethanol extract of Camellia sinensis leaf ameliorates insulin secretion, inhibits the DPP-IV enzyme, improves glucose tolerance, and increases active GLP-1 (7–36) levels in high-fat-diet-fed rats. Medicines. 2022 Nov 11;9(11):56.
3. Fu, Q. Y., Li, Q. S., Lin, X. M., Qiao, R. Y., Yang, R., Li, X. M., ... & Liang, Y. R. (2017). Antidiabetic effects of tea. Molecules, 22(5), 849.
4. Mousavi A, Vafa M, Neyestani T, Khamseh M, Hoseini F. The effects of green tea consumption on metabolic and anthropometric indices in patients with type 2 diabetes. Journal of research in medical sciences: the official journal of Isfahan University of Medical Sciences. 2013 Dec;18(12):1080.
5. Salim KS. Hypoglycemic property of ginger and green tea and their possible mechanisms in diabetes mellitus. In The Open Conference Proceedings Journal 2014 (Vol. 5, No. 1, pp. 13-19).
6. Bae KC, Park JH, Na AY, Kim SJ, Ahn S, Kim SP, Oh BC, Cho HC, Kim YW, Song DK. Effect of green tea extract/poly-γ-glutamic acid complex in obese type 2 diabetic mice. Diabetes & metabolism journal. 2013 Jun;37(3):196-206.
7. Ueda-Wakagi M, Nagayasu H, Yamashita Y, Ashida H. Green tea ameliorates hyperglycemia by promoting the translocation of glucose transporter 4 in the skeletal muscle of diabetic rodents. International journal of molecular sciences. 2019 May 16;20(10):2436.
8. Zakir M, Sultan K, Munir Y, Ahmad S, Amin S, Khan MA, Khan H. Biofunctional beverage: Antihyperglycemic effect of green tea in alloxan induced diabetic rabbits. Current Bioactive Compounds. 2019 Feb 1;15(1):120-4.
9. Toolsee NA, Aruoma OI, Gunness TK, Kowlessur S, Dambala V, Murad F, Googoolye K, Daus D, Indelicato J, Rondeau P, Bourdon E. Effectiveness of green tea in a randomized human cohort: relevance to diabetes and its complications. BioMed Research International. 2013;2013(1):412379.
10. Salah H, Moussa E, Atta M, Bakr SE, Farrag F, Hafez A. Green Tea Mitigates Streptozotocin-Induced Diabetic Mice Through Anti-Fibrotic Activity and Modulation of Proinflammatory Cytokines. Slovenian Veterinary Research. 2019 Mar 5;56(22-Suppl).
11. Wiyono N, Yudhani RD, Wasita B, Suyatmi S, Wardhani LO, Pesik RN, Yarsa KY, Rahayu RF. Exploring the therapeutic potential of functional foods for diabetes: A bibliometric analysis and scientific mapping. Narra J. 2024 Jan 27;4(1):e382.
12. Ahmida MH, Abuzogaya MH. The effects of oral administration of green tea and ginger extracts on serum and hepatic lipid content in rats fed a hyperlipidemic diet. Der Pharmacia Letter. 2009 1(1) 56-64.
13. Fajrin FN, Prabowo I, Safira L. Literature Review: Green Tea Extract Potency (Camellia sinensis) in Lowering Overweight Glycemic Index of a Wistar Rat. Journal of Research in Pharmacy and Pharmaceutical Sciences. 2022 Dec 28;1(2):43-9.
14. Boon N. Health potential for functional green teas?. International journal for vitamin and nutrition research. 2008 Dec 1;78(6):275-81.
15. Alkhudaydi HM, Spencer JP. A comparison of the effects of green tea and cocoa on glycaemic control and insulin sensitivity in patients with type 2 diabetes mellitus: A systematic review and meta-analysis. Nutrition and Healthy Ageing. 2024 Oct;9(1):17-36.
16. Oktaviani SR, Nabilah UU. Anti diabetic Activity of Green Tea and Black Tea (In Vivo). FoodTech: Jurnal Teknologi Pangan.;7(2):1-8.
17. Ali RB, Almokhtar MN. Camellia Sinensis (Green Tea) Health Benefits. Journal of Medical Sciences. 2023 Aug 25;18(2):1-7.
18. Zhao T, Li C, Wang S, Song X. Green tea (Camellia sinensis): A review of its phytochemistry, pharmacology, and toxicology. Molecules. 2022 Jun 18;27(12):3909.
19. Akalın K, Ekiz AT, Karakaya F, Karadag A, Pelvan E, Doğan K, Alasalvar C, Aksu S. In vivo antidiabetic activities of green and black tea polysaccharides using streptozotocin-induced diabetic mice fed with a high-fat diet. Journal of Food Bioactives. 2019 Dec 31;8.
20. Kalauni SK, Karki J, Sharma M, Khanal LN. Phytochemical screening, evaluation of antioxidant and antidiabetic activities of green tea available in Nepal. Prithvi Academic Journal. 2024 May 13;7:9-19.
21. Oh J, Jo SH, Kim JS, Ha KS, Lee JY, Choi HY, Yu SY, Kwon YI, Kim YC. Selected tea and tea pomace extracts inhibit intestinal α-glucosidase activity in vitro and postprandial hyperglycemia in vivo. International journal of molecular sciences. 2015 Apr 21;16(4):8811-25.
22. Ito A, Matsui Y, Takeshita M, Katashima M, Goto C, Kuriki K. Gut microbiota-mediated associations of green tea and catechin intakes with glucose metabolism in individuals without type 2 diabetes mellitus: A four-season observational study with mediation analysis. Archives of Microbiology. 2023 May;205(5):191.
23. Wu G, Liu AB, Xu Y, Wang Y, Zhao L, Hara Y, Lam YY, Yang CS. The effects of green tea on diabetes and gut microbiome in db/db mice: studies with tea extracts vs. Tea powder. Nutrients. 2021 Sep 10;13(9):3155.
24. Hijazi MM, Khatoon N, Azmi MA, Rajput MT, Hussain Zaidi SI, Azmi MA, Perveen R, Hassan Naqvi SN, Rashid M. Effects of Camellia sinensis L.(green tea) extract on the body and testicular weight changes in adult Wistar rats. Pakistan Journal of Pharmaceutical Sciences. 2015 Jan 1;28(1).
25. Al-Hilfy JH. Effect of green tea aqueous extract on body weight, glucose level, and kidney functions in diabetic male albino rats. Al-Nahrain Journal of Science. 2012 Sep 1;15(3):116-66.
26. Du LL, Fu QY, Xiang LP, Zheng XQ, Lu JL, Ye JH, Li QS, Polito CA, Liang YR. Tea polysaccharides and their bioactivities. Molecules. 2016 Oct 30;21(11):1449.
27. Abu-Alkaseem BA, Hamzah MI, Raghif AR. Effect of Ethyl Acetate Fraction of Silybum Marianum and Ficus Carica Leaves Extract on Biochemical Parameters and Histopathological Outcomes Obtained in Streptozotocin-induced T2DM Rats.Journal of Chemical Health Risks. 2023 13(3).
28. Tsuneki H, Ishizuka M, Terasawa M, Wu JB, Sasaoka T, Kimura I. Effect of green tea on blood glucose levels and serum proteomic patterns in diabetic (db/db) mice and on glucose metabolism in healthy humans. BMC pharmacology. 2004 Dec;4(1):1-0.
29. Wein S, Schrader E, Rimbach G, Wolffram S. Oral green tea catechins transiently lower plasma glucose concentrations in female db/db mice. Journal of medicinal food. 2013 Apr;16(4):312-7.
30. Jia MJ, Liu XN, Liang YC, Liu DL, Li HL. The effect of green tea on patients with type 2 diabetes mellitus: A meta-analysis. Medicine. 2024 Nov 22;103(47):e39702.
31. Xu R, Yang K, Li S, Dai M, Chen G. Effect of green tea consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials. Nutrition journal. 2020 Sep 16;19(1):48.
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Rabyah B. Ali, Mustafa N.Almokhtar, Hana M. Kamoka (Author)
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Open Access Policy
Libyan journal of medical Research (LJMR).is an open journal, therefore there are no fees required for downloading any publication from the journal website by authors, readers, and institution.
The journal applies the license of CC BY (a Creative Commons Attribution 4.0 International license). This license allows authors to keep ownership f the copyright of their papers. But this license permits any user to download , print out, extract, reuse, archive, and distribute the article, so long as appropriate credit is given to the authors and the source of the work.
The license ensures that the article will be available as widely as possible and that the article can be included in any scientific archive.
Editorial Policy
The publication of an article in a peer reviewed journal is an essential model for Libyan journal of medical Research (LJMR). It is necessary to agree upon standards of expected ethical behavior for all parties involved in the act of publishing: the author, the journal editorial, the peer reviewer and the publisher.
Any manuscript or substantial parts of it, submitted to the journal must not be under consideration by any other journal. In general, the manuscript should not have already been published in any journal or other citable form, although it may have been deposited on a preprint server. Authors are required to ensure that no material submitted as part of a manuscript infringes existing copyrights, or the rights of a third party.
Authorship Policy
The manuscript authorship should be limited to those who have made a significant contribution and intellectual input to the research submitted to the journal, including design, performance, interpretation of the reported study, and writing the manuscript. All those who have made significant contributions should be listed as co-authors.
Others who have participated in certain substantive aspects of the manuscript but without intellectual input should only be recognized in the acknowledgements section of the manuscript. Also, one of the authors should be selected as the corresponding author to communicate with the journal and approve the final version of the manuscript for publication in the LJMR.
Peer-review Policy
- All the manuscripts submitted to LJMR will be subjected to the double-blinded peer-review process;
- The manuscript will be reviewed by two suitable experts in the respective subject area.
- Reports of all the reviewers will be considered while deciding on acceptance/revision or rejection of a manuscript.
- Editor-In-Chief will make the final decision, based on the reviewer’s comments.
- Editor-In-Chief can ask one or more advisory board members for their suggestions upon a manuscript, before making the final decision.
- Associate editor and review editors provide administrative support to maintain the integrity of the peer-review process.
- In case, authors challenge the editor’s negative decision with suitable arguments, the manuscript can be sent to one more reviewer and the final decision will be made based upon his recommendations.
https://portal.issn.org/resource/ISSN/2413-6069
