New research further sheds light on green tea's role in improving obesity-related metabolic issues. Researchers have found that multiple active ingredients in green tea can reprogram muscle metabolism and improve insulin sensitivity and glucose tolerance, providing more scientific evidence for green tea's long-standing claim to help prevent obesity.
Much of the previous evidence that green tea promotes blood sugar control and reduces the risk of metabolic diseases mostly comes from animal experiments in low-temperature laboratory environments, which may mask the true physiological effects due to the additional caloric consumption induced by the environment. This time, the research team of Brazil's Cruzeiro do Sul University set the experimental temperature at 28°C and allowed the mice to consume a high-fat "buffet diet" and then supplemented it with green tea extract. The caloric density of this high-fat diet is 531 kcal/100 grams, which is almost twice that of the standard diet. During the experiment, the researchers provided mice with daily high-energy foods such as chocolate, sandwich biscuits, and milk candies. The mice were divided into three groups: standard group, high-fat group and high-fat + green tea group. The green tea group began to supplement daily extract after 4 weeks of high-fat diet.
The results showed that compared with the high-fat diet group alone, the glucose tolerance and insulin sensitivity of the mice in the green tea group were significantly improved, and fasting blood sugar was also lower. This means that even excluding environmental caloric consumption, green tea can still help improve metabolic function. At the same time, the cross-sectional area of skeletal muscle fibers in these mice increased, the expression of genes related to glucose processing (such as Insr, Irs1, Glut4, etc.) increased, and the levels of the key metabolic enzyme lactate dehydrogenase (LDH) returned to normal.
Research leader Otto pointed out that the increase in muscle fiber diameter means that the muscle function is more active, and green tea can protect muscle structure in obesity. The study also found that the benefits of green tea depended on the protein hormone adiponectin secreted by adipocytes, and no metabolic improvement was observed in adiponectin-free mice, suggesting that this hormone is one of the key mechanisms by which green tea exerts its effects.
It is worth noting that the research team did not confirm that a specific single ingredient in green tea is the only source of health benefits. They believe that the synergistic effect of multiple active substances constitutes the overall advantages of green tea. The dose of green tea tested on animals is about three cups for humans, but scientists warn that the actual effect is still affected by product quality and polyphenol content. Daily continuous drinking is closer to the healthy habits of Asian people, rather than short-term drinking in the hope of rapid weight loss.
Research suggests that long-term drinking of green tea may improve obesity-related muscle glucose metabolism and insulin sensitivity, but the specific translation into human health effects requires more clinical data to support. The research has been published in the journal Cell Biochemistry & Function.