Plain language summary
Obesity is associated with low-grade inflammation and oxidative stress, both of which play roles in the development of many obesity-related diseases and metabolic imbalances. Previous studies show that green tea (GT) supplementation may have favourable effects on body weight and body composition, and there’s growing evidence for its use in the prevention of obesity and coexisting diseases. The aim of this randomised double-blind trial was to assess the effects of supplementation with GT extract on body mass, glucose levels, mineral concentrations, lipid profile and antioxidant status in obese patients. The study included 46 obese participants, who received either 379 mg GT extract or placebo daily for three months. The study found that 3-month supplementation with GT extract significantly decreased body mass index, waist circumference, total cholesterol, LDL cholesterol, triglycerides, glucose and iron levels, while the levels of HDL cholesterol, total anti-oxidants, magnesium and zinc were increased. The authors conclude that GT extract may be beneficial in improving antioxidant and mineral status, body mass index, lipid profile and glucose levels in obese people.
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.
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