Effects of Green Tea Supplementation on Elements, Total Antioxidants, Lipids, and Glucose Values in the Serum of Obese Patients

Danuta Pupek-Musialik,Anna Jablecka,Joanna Suliburska,Monika Szulinska,Marta Stepien,Pawel Bogdanski

doi:10.1007/s12011-012-9448-z

Abstract

The consumption of green tea has been associated with cardiovascular and metabolic diseases. There have been some studies on the influence of green tea on the mineral status of obese subjects, but they have not yielded conclusive results. The aim of the present study is to examine the effects of green tea extract on the mineral, body mass, lipid profile, glucose, and antioxidant status of obese patients. A randomized, double-blind, placebo-controlled study was conducted. Forty-six obese patients were randomly assigned to receive either 379 mg of green tea extract, or a placebo, daily for 3 months. At baseline, and after 3 months of treatment, the anthropometric parameters, blood pressure, and total antioxidant status were assessed, as were the levels of plasma lipids, glucose, calcium, magnesium, iron, zinc, and copper. We found that 3 months of green tea extract supplementation resulted in decreases in body mass index, waist circumference, and levels of total cholesterol, low-density cholesterol, and triglyceride. Increases in total antioxidant level and in zinc concentration in serum were also observed. Glucose and iron levels were lower in the green tea extract group than in the control, although HDL-cholesterol and magnesium were higher in the green tea extract group than in the placebo group. At baseline, a positive correlation was found between calcium and body mass index, as was a negative correlation between copper and triglycerides. After 3 months, a positive correlation between iron and body mass index and between magnesium and HDL-cholesterol, as well as a negative correlation between magnesium and glucose, were observed. The present findings demonstrate that green tea influences the body's mineral status. Moreover, the results of this study confirm the beneficial effects of green tea extract supplementation on body mass index, lipid profile, and total antioxidant status in patients with obesity.

Highlights

Overweight and obesity represent rapidly growing threats to the health of populations in an increasing numbers of countries worldwide
The present findings demonstrate strong evidence for the effect of green tea extract (GTE) on the mineral status of obese people
Our results suggest that green tea (GT) improves the status of Zn and Mg in such individuals

Summary

Introduction

Overweight and obesity represent rapidly growing threats to the health of populations in an increasing numbers of countries worldwide. Oxidative stress consists of unbalanced higher cellular levels of reactive oxygen species (ROS), e.g., superoxide and hydroxyl radicals and cellular antioxidant defense [3]. Blood may be vulnerable to oxidative stress induced by diabetes and may become exposed to ROS continuously generated by the auto-oxidation of hemoglobin and polyunsaturated fatty acids (PUFAs) [4, 5]. Because of their high rate of oxygen consumption, their high content of PUFAs, and their poor enzymatic antioxidant defense, blood cells exhibit increased vulnerability to diabetes-induced oxidative stress [4, 5]. In order to scavenge ROS, various enzymatic and nonenzymatic antioxidant defense systems exist in the blood [7]

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