Green Tea Could Help Prevent Diabetes and Its Complications

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By Agata P. | Updated: Feb 06, 2024

Green Tea Could Help Prevent Diabetes and Its Complications
General Information
  • 12 Sep 2013
  • Mauritius
  • American University of Health Sciences
  • Toolsee, N. A. et al
  • Clinical trial
  • 155 adults
  • 16 weeks

To date, numerous health benefits have been attributed to green tea, including cardiovascular, anti-inflammatory, and neuroprotective properties, among others.1 Most of these beneficial effects are linked to green tea's high levels of polyphenols. To expand its therapeutic uses even further, Mauritian researchers evaluated potential benefits of green tea for diabetes.

The Study

This randomized, controlled clinical trial recruited 155 prediabetic adults, divided into two groups: the experimental group and the control group. The results were published in the BioMed Research International journal.

For 14 weeks, the experimental group drank three cups of green tea per day before meals, while the control group drank an equivalent amount of warm water. There was a 2-week washout period that followed the intervention period.

Besides evaluating the effects of green tea on diabetes-related health parameters (such as waist-hip ratio, glucose levels, etc.), researchers also assessed the phytophenolic composition and antioxidant potential of local green tea.

The Results

Green tea consumption was well tolerated by the participants. Procyanidin B2 was found to be the most abundant compound in Mauritian green tea. Procyanidin B2 is a flavonoid with potent antioxidant activities.

Women in the control group had a significant increase of waist-hip ratio, whereas those in the experimental group did not experience any increases. Waist-hip ratio is considered an indicator of obesity, which is a risk factor for diabetes.

Male participants in the experimental group had a small reduction in ferritin levels, while those in the control group had a considerable increase of 39.2%. Elevated ferritin levels are associated with type 2 diabetes.

The levels of alanine aminotransferase (ALT), a marker of liver function, decreased significantly in women in the experimental group (by 13%). Women in the control group did not experience any ALT reductions.

What Does this Mean?

The results of this study provide an answer to a common question, “Is green tea good for diabetes?”. It has shown that drinking green tea as part of a healthy lifestyle may help prevent metabolic syndrome and the associated risk of diabetes.

These findings are supported by results of another study, in which daily consumption of green tea was linked to a 10% lower risk of death from type 2 diabetes.2

Other herbs that may offer benefits for diabetes management include ginger, yacon, and cinnamon.


  • BioMed Research International, Effectiveness of Green Tea in a Randomized Human Cohort: Relevance to Diabetes and Its Complications, 2013


  1. Chinese Medicine. (2010). Beneficial effects of green tea: A literature review. Retrieved November 18, 2021, from
  2. The American Journal of Clinical Nutrition. (2021). Tea consumption and long-term risk of type 2 diabetes and diabetic complications: A cohort study of 0.6 million Chinese adults. Retrieved November 18, 2021, from