Health risks for patients suffering from diabetes and heart diseases increase if the patients are overweight. Chemicals in green tea, along with caffeine, are thought to burn fat and reduce weight. They also improve body measurement parameters like body mass index, waist circumference and waist-to-hip ratio. This systematic review of previous research trials had conflicting results; it found that though green tea intake reduces weight, the effects are modest. The present data do not imply that green tea alone can change all body measurements.
The obesity epidemic and its associated health risks have prompted researchers to look for various natural substances that can control weight. People who consume tea habitually have been found to have a lesser percentage of body fat and waist circumference than those who do not drink tea. Ninety percent of habitual tea drinkers in one study drank green tea, which naturally has caffeine. This suggested that catechins and other chemicals in green tea might play a part in weight loss. It is believed that catechins in green tea facilitate weight reduction by increasing energy expenditure and the burning of fat. “Because of caffeine’s independent effects, the combination of GTC’s with caffeine may be able to provide additive, or even synergistic benefit, over GTCs alone.” But it is not known how significant this effect is. The present study reviewed various published papers on the subject.
* This is a review of previously published research that consists of an analysis of results from different studies.
* Previous papers available on Internet databases like MEDLINE, EMBASE and the Natural Medicines Comprehensive Database were searched for studies mentioning green tea, body weight, metabolic syndrome, and obesity.
* A total of 15 studies involving 1,243 patients were found.
* The average duration of studies was between 8 and 24 weeks. Green tea was consumed either as tea extract capsules or green tea beverages.
* Some studies used caffeine in the control group; some did not use caffeine as a control.
* Drinking green tea along with caffeine reduced body mass index (BMI) by 0.58, as compared to the BMI of those in the control group.
* Drinking green tea along with caffeine lowered body weight by around 3.4 lbs., as compared to the weight of those in the control group.
* Waist circumference decreased in people drinking green tea, but the effect was not significant. The waist-to-hip ratio did not change significantly.
The studies targeted populations including healthy adults, adults with disease and children. It is challenging to determine which group would benefit most by drinking green tea. Also, the dose ranged from 583 to 714 mg/day. Though there were no side effects of green tea consumption reported in these papers, a few other studies reported liver toxicity related to green tea consumption. More research on dose range and safety aspects is needed.
This review of 15 previous studies indicates that drinking green tea might be beneficial to overweight patients. This study chose to look at the effects of green tea on parameters like BMI, waist circumference, body weight and waist-to-hip ratio, because these are used as significant diagnostic markers. They help identify overweight and obesity, and are also considered “independent risk factors for cardiovascular disease and diabetes.” The study shows that drinking green tea leads to weight loss and reduction in waist circumference. However, the extent of the effect seems small and might not be clinically relevant to patients. Further research is required before accepting green tea as a dietary therapy for health management in overweight patients.
For More Information:
Effect of Green Tea Catechins with or Without Caffeine on Anthropometric Measures: A Systematic Review and Meta-Analysis
Publication Journal: The American Journal of Clinical Nutrition, 2010
By Olivia J. Phung; William L. Baker; University of Connecticut School of Pharmacy, Storrs, Connecticut, and the Department of Drug Information at Hartford Hospital, Hartford, Connecticut