Low-caffeine green tea supplementation reduced lithium serum levels and the relative abundance of microbiota in women with obesity: A case study

Background

Green tea (GT) polyphenols play an important and known role in the oxidative and inflammatory response due to their antioxidant, anti-inflammatory, anti-hyperglycemic, and anti-obesity properties. However, its relation to the detoxification of toxic metals and its possible effect remains unknown.

Purpose

The present study investigated the relationship between GT intake, toxic metals detoxification, and gut microbiota in obesity.

Methods

Each participant in the group initially received 56 capsules of low-caffeine GT from the Solaray® brand. After four weeks of supplementation, another 56 capsules were given, totaling 112. All assessments were performed pre- and post-GT intervention. Serum metal levels were determined using an inductively coupled plasma mass spectrometer (PerkinElmer, NexION 2000 B, Waltham, MA, EUA, EUA). Fecal DNA was extracted using the QIAmp® Fast DNA Stool MiniKit (QIAGEN).

Results

Intervention with GT did not promote changes in the clinical or metabolic data evaluated. However, GT supplementation led to a significant decrease of 48% in Lithium concentration in the post-intervention period compared to the pre-intervention period. This study also observes the prebiotic effect of green tea in modulating Bacteroidetes and Firmicutes.

Conclusions

The GT effect of Lithium reduction is a new finding in the literature. There is a lack of investigation to address the effects of the components of the GT in lithium excretion, and we attribute this effect to the trace amount of caffeine.