Clinical Trial on the Effect of Ripened Pu-erh Tea on Improving Abnormal Glucose and Lipid Metabolism

This study explored the effect of commercial ripened Pu-erh tea (Y562, China Tea (Yunnan) Industry Co. Ltd.) on improving the health of populations with abnormal glucose and lipid metabolism. Qualified volunteers were recruited for nutritional epidemiological and clinical intervention studies. The volunteers were asked to drink the tea for three months. Their body composition (body mass, body mass index (BMI), body fat ratio and visceral fat), body circumferences (waist circumference, hip circumference and neck circumference), glucose metabolism-related indicators (fasting blood glucose, insulin, C-peptide, glycosylated hemoglobin), lipid metabolism-related indicators (total cholesterol, triglycerides, highdensity lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein A1 and B), blood uric acid levels, liver fat contents, and gut microbiota were tested and compared before and after drinking the tea to explore its health benefits. The results showed that after drinking Y562 without any change in diet or exercise for three months, the body mass, BMI, body circumferences, blood lipids (high-density lipoprotein cholesterol, apolipoprotein A1 and B), and liver fat contents of the volunteers were significantly improved (P < 0.05). Blood glucose (fasting blood glucose, insulin, C-peptide, insulin resistance, and glycosylated hemoglobin), triglyceride, and uric acid levels were also improved, but without any statistical significance (P > 0.05). Moreover, the gut microbiota was improved, showing increased uniformity. The relative abundance of Lactobacillus, Clostridium, Akkermansia muciniphila, Clostridium screenens and Streptococcus thermophilus was increased, while that of Streptococcus, Lactococcus, Bacteroides, Bifidobacterium and Paraacteroides distasonis was decreased. This study suggests that ripened Pu-erh tea Y562 has the potential to help reduce the body mass, improve the body shape, reduce blood glucose and lipids, and alleviate non-alcoholic fatty liver disease (NAFLD). The underlying mechanism may be related to the regulation of the intestinal microecology and the bile acid pathways by Pu-erh tea.