Green Tea Shows Promise in Combating Obesity and Insulin Resistance
Green tea, long recognized for its medicinal and antioxidant properties, is now the focus of research exploring its potential to address metabolic diseases like obesity and type 2 diabetes. A recent study conducted by Professor Rosemari otton of the Institute of Health Sciences at Cruzeiro do Sul University in São Paulo, Brazil, demonstrated significant improvements in weight loss and insulin resistance in obese mice treated with green tea extract. The findings were published in the journal Cell Biochemistry & Function.
Professor Otton, who has dedicated over 15 years to researching green tea, and her team fed mice a “western-type” diet – high in fat and calories and consisting of foods like chocolate, filled biscuits, milk jam, and condensed milk – for four weeks. Following this initial period,the mice were administered a standardized green tea extract for 12 weeks while continuing on the same high-calorie diet.
The dosage administered was 500 mg of green tea extract per kilogram of body weight, equivalent to approximately 3 grams of green tea, or three cups, per day for humans. Professor Otton cautions that the quality of commercially available tea bags can vary, recommending standardized green tea extracts available in pharmacies to ensure a consistent intake of beneficial flavonoids.
The study also controlled for environmental factors,maintaining a constant temperature of 28°C - a departure from the typical 22°C found in many animal laboratories. Professor Otton explained that lower temperatures can cause mice to expend energy maintaining body temperature, perhaps masking the true effects of the substance being tested. Maintaining a “thermoneutral” surroundings allowed the team to isolate the effects of the green tea.
Beyond weight loss and improved insulin sensitivity, the research revealed a protective effect of green tea against obesity-related muscle atrophy. Typically, obesity leads to a reduction in muscle fiber diameter, but green tea treatment prevented this change and restored normal activity of genes related to glucose metabolism in muscles.
Interestingly, the study found green tea was only effective in overweight animals, suggesting it acts specifically within an environment of excess nutrients, targeting fat cells directly. When individual components of green tea were tested, the whole extract consistently proved more effective, potentially due to synergistic interactions between its compounds. The protein adiponectin also played a crucial role,as the green tea’s effects were absent in mice lacking this protein.
While the results are encouraging,Professor Otton emphasizes that a safe and effective dosage for humans remains to be persistent. “Every person’s metabolism is different,” she stated, suggesting that long-term, regular consumption, similar to practices in Asian countries, is the most promising approach. “Rather of drinking it for five months and waiting for a miracle, it is indeed necessary to make it a lifelong habit.”
