Nutritional Supplement

Green Tea

Also indexed as: Camellia sinensis, EGCG

  • Negative Interactions

    3

    • Green Tea

      Cardec DM

      Reduces Effectiveness

      Tannins are a group of unrelated chemicals that give plants an astringent taste. Herbs containing high amounts of tannins may interfere with the absorption of ephedrine or pseudoephedrine taken by mouth. Herbs containing high levels of tannins include green tea, black tea, uva ursi (Arctostaphylos uva-ursi), black walnut (Juglans nigra),red raspberry (Rubus idaeus), oak (Quercus spp.), and witch hazel (Hamamelis virginiana).

      Cardec DM
      Green Tea
      ×
      1. Brinker F. Interactions of pharmaceutical and botanical medicines. J Naturopathic Med 1997;7(2):14-20.

    • Green Tea

      Nadolol

      Reduces Effectiveness
      In a study of healthy volunteers, ingestion of green tea along with nadolol decreased the absorption of the drug and decreased its blood pressure-lowering effect. Based on this report, people taking nadolol should not consume green tea.
      Nadolol
      Green Tea
      ×
      1. Misaka S, Yatabe J, Muller F, et al. Green tea ingestion greatly reduces plasma concentrations of nadolol in healthy subjects. Clin Pharmacol Ther 2014;95:432–8.

    • Green Tea

      Warfarin

      Reduces Effectiveness

      One man taking warfarin and one-half to one gallon of green tea (Camellia sinensis) per day developed signs based on laboratory testing suggesting his blood was too thick because the green tea was blocking the effect of warfarin. Removal of the green tea caused normalization of his blood tests. Those taking green tea and warfarin together should have their blood monitored regularly to avert any problems and should consult with a doctor, healthcare practitioner and/or pharmacist before taking any medication.

      Warfarin
      Green Tea
      ×
      1. Taylor JR, Wilt VM. Probable antagonism of warfarin by green tea. Ann Pharmacother 1999;33:426-8.

References

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23. You SQ. Study on feasibility of Chinese green tea polyphenols (CTP) for preventing dental caries. Chin J Stom 1993;28(4):197-9.

24. Hamilton-Miller JM. Antimicrobial properties of tea (Camellia sinensis L.). Antimicrob Agents Chemother 1995;39:2375-7.

25. Imai K, Nakachi K. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases. BMJ 1995;310:693-6.

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33. Hibi M, Takase H, Iwasaki M, et al. Efficacy of tea catechin-rich beverages to reduce abdominal adiposity and metabolic syndrome risks in obese and overweight subjects: a pooled analysis of 6 human trials. Nutr Res 2018;55:1–10.

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39. Quezada-Fernandez P, Trujillo-Quiros J, Pascoe-Gonzalez S, et al. Effect of green tea extract on arterial stiffness, lipid profile and sRAGE in patients with type 2 diabetes mellitus: a randomised, double-blind, placebo-controlled trial. Int J Food Sci Nutr 2019:1–9.

40. Liu K, Zhou R, Wang B, et al. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. Am J Clin Nutr 2013;98:340–8.

41. Yu J, Song P, Perry R, et al. The Effectiveness of Green Tea or Green Tea Extract on Insulin Resistance and Glycemic Control in Type 2 Diabetes Mellitus: A Meta-Analysis. Diabetes Metab J 2017;41:251–62.

42. Younes M, Aggett P, Aguilar F, et al. Scientific opinion on the safety of green tea catechins. EFSA Journal 2018;16:e05239.

43. Landini L, Rebelos E, Honka MJ. Green Tea from the Far East to the Drug Store: Focus on the Beneficial Cardiovascular Effects. Curr Pharm Des 2021;27:1931–40.

44. Xu R, Yang K, Li S, et al. Effect of green tea consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials. Nutr J 2020;19:48.

45. Asbaghi O, Fouladvand F, Moradi S, et al. Effect of green tea extract on lipid profile in patients with type 2 diabetes mellitus: A systematic review and meta-analysis. Diabetes Metab Syndr 2020;14:293–301.

46. Yuan F, Dong H, Fang K, et al. Effects of green tea on lipid metabolism in overweight or obese people: A meta-analysis of randomized controlled trials. Mol Nutr Food Res 2018;62.

47. Momose Y, Maeda-Yamamoto M, Nabetani H. Systematic review of green tea epigallocatechin gallate in reducing low-density lipoprotein cholesterol levels of humans. Int J Food Sci Nutr 2016;67:606–13.

48. Eng QY, Thanikachalam PV, Ramamurthy S. Molecular understanding of Epigallocatechin gallate (EGCG) in cardiovascular and metabolic diseases. J Ethnopharmacol 2018;210:296–310.

49. Tsubono Y, Tsugane S. Green tea intake in relation to serum lipid levels in middle-aged Japanese men and women. Ann Epidemiol 1997;7:280-4.

50. Imai K, Nakachi K. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases. BMJ 1995;310:693-6.

51. Rothenberg DO, Zhou C, Zhang L. A Review on the Weight-Loss Effects of Oxidized Tea Polyphenols. Molecules (Basel, Switzerland). 2018 May;23(5).

52. Vázquez Cisneros LC, López-Uriarte P, López-Espinoza A, et al. Effects of green tea and its epigallocatechin (EGCG) content on body weight and fat mass in humans: a systematic review Nutricion Hospitalaria. 2017 06;34(3):731–737.

53. Jurgens TM, Whelan AM, Killian L, et al. Green tea for weight loss and weight maintenance in overweight or obese adults. The Cochrane Database of Systematic Reviews. 2012 Dec;12:CD008650.

54. Huang J, Wang Y, Xie Z, et al. The anti-obesity effects of green tea in human intervention and basic molecular studies. European Journal of Clinical Nutrition. 2014 Oct;68(10):1075–87.

55. Okla M, Kim J, Koehler K, et al. Dietary Factors Promoting Brown and Beige Fat Development and Thermogenesis. Advances in Nutrition (Bethesda, Md.). 2017 May;8(3):473–483.

56. Graham HN. Green tea composition, consumption, and polyphenol chemistry. Prev Med 1992;21:334-50.

57. Kim J, Hwang JS, Cho YK, et al. Protective effects of (-)-epigallocatechin-3-gallate on UVA- and UVB-induced skin damage. Skin Pharmacol Appl Skin Physiol 2001;14:11-9.

58. Katiyar SK. Skin photoprotection by green tea: antioxidant and immunomodulatory effects. Curr Drug Targets Immune Endocr Metabol Disord 2003;3:234-42 [review].

59. Katiyar SK, Perez A, Mukhtar H. Green tea polyphenol treatment to human skin prevents formation of ultraviolet light B-induced pyrimidine dimers in DNA. Clin Cancer Res 2000;6:3864-9.

60. Elmets CA, Singh D, Tubesing K, et al. Cutaneous photoprotection from ultraviolet injury by green tea polyphenols. J Am Acad Dermatol 2001;44:425-32.

61. Bettuzzi S, Brausi M, Rizzi F, et al. Chemoprevention of human prostate cancer by oral administration of green tea catechins in volunteers with high-grade prostate intraepithelial neoplasia: a preliminary report from a one-year proof-of-principle study. Cancer Res 2006;66:1234-40.

62. Stoner GD, Mukhtar H. Polyphenols as cancer chemopreventive agents. J Cell Bioch 1995;22:169-80.

63. You SQ. Study on feasibility of Chinese green tea polyphenols (CTP) for preventing dental caries. Chin J Stom 1993;28(4):197-9.

64. Hamilton-Miller JM. Antimicrobial properties of tea (Camellia sinensis L.). Antimicrob Agents Chemother 1995;39:2375-7.

65. Matsuo N, Yamada K, Shoji K, et al. Effect of tea polyphenols on histamine release from rat basophilic leukemia (RBL-2H3) cells: the structure-inhibitory activity relationship. Allergy 1997;52:58-64.

66. Plein K, Burkard G, Hotz J. Treatment of chronic diarrhea in Crohn disease. A pilot study of the clinical effect of tannin albuminate and ethacridine lactate. Fortschr Med 1993;111:114-8 [in German].

67. Li N, Sun Z, Han C, Chen J. The chemopreventive effects of tea on human oral precancerous mucosa lesions. Proc Soc Exp Biol Med 1999;220:218-24.

68. Ahn WS, Yoo J, Huh SW, et al. Protective effects of green tea extracts (polyphenon E and EGCG) on human cervical lesions. Eur J Cancer Prev 2003;12:383-90.

69. Murray MT. The Healing Power of Herbs. Rocklin, CA: Prima Publishing, 1995, 192-6.

70. Imai K, Suga K, Nakachi K. Cancer-preventive effects of drinking green tea among a Japanese population. Prev Med 1997;26:769-75.

71. Imai K, Nakachi K. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases. BMJ 1995;310:693-6.

72. Samman S, Sandstrom B, Toft MB, et al. Green tea or rosemary extract added to foods reduces nonheme-iron absorption. Am J Clin Nutr 2001;73:607-12.

73. Bonkovsky HL. Hepatotoxicity associated with supplements containing Chinese green tea (Camellia sinensis). Ann Intern Med 2006;144:68-71.

74. Schonthal AH. Adverse effects of concentrated green tea extracts. Mol Nutr Food Res 2011;55:874-885.

75. Oketch-Rabah HA, Roe AL, Rider CV, et al. United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts. Toxicol Rep 2020;7:386–402.

76. Liatsos GD, Moulakakis A, Ketikoglou I, Klonari S. Possible green tea-induced thrombotic thrombocytopenic purpura. Am J Health Syst Pharm 2010;67:531-4.

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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2024.