Liupao tea improves metabolic syndrome risks in clinical trial

By Dr. Liji Thomas, MDReviewed by Lauren HardakerJul 23 2025

New research shows that Liupao tea could be a powerful, natural tool for those battling metabolic syndrome, improving heart health, weight, and even gut balance in just three months.

Study: A Randomized Double-Blind Trial of the Effect of Liupao Tea on Metabolic Parameters, Body Composition, and Gut Microbiota in Adults with Metabolic Syndrome. Image credit: Lao Ma/Shutterstock.com

Metabolic syndrome is a cluster of chronic metabolic diseases, also called Syndrome X. It increases the rate of medical consultations and hospitalizations and triples medical expenses, especially when it includes more medical conditions. A recent study, published in Nutrients, explored the potential role of Liupao tea in alleviating its impact by improving metabolic health.

Introduction

Metabolic syndrome has become common worldwide as people shift to cities, become sedentary, and adopt less healthy diets. For instance, 22% of the Chinese population has metabolic syndrome. This has led to the early initiation of preventive therapies, including plant-based phytochemical-rich functional foods.

Much evidence suggests that black and green tea protect against metabolic syndrome and deaths from cancer, cardiovascular disease, and all causes. For example, in background studies, women who drink hot tea are likely to have a lower body weight, waist circumference, and fasting blood sugar; in men, it is linked to higher ‘good’ cholesterol (high-density lipoprotein, HDL) levels. However, the current clinical trial did not directly assess these gender-specific effects.

Dark tea

Dark tea is produced by fermentation, unlike ordinary tea. The process promotes synergistic activity by microbes and polyphenol oxidase, increasing the concentration of catechin-derived active compounds like theabrownin and tea polysaccharides. These bioactives explain the anti-inflammatory, cholesterol-lowering, and prebiotic attributes of tea.

Liupao tea is a dark tea variety rich in polyphenols and theabrownin. In preclinical trials, it improved glucose metabolism and reduced body weight in obese subjects. It also reduced markers of obesity-related liver damage and fat buildup. However, these effects have mostly been shown in animal studies; human data has been limited until now.

About the study

The current study sought to explore how Liupao tea affects metabolic syndrome markers and the gut microbiota and how it affects the metabolic state in these patients. The aim was to provide evidence to back its use as a functional beverage in metabolic syndrome. The investigators conducted a randomized double-blind trial, assigning patients with metabolic syndrome to four groups.

Participants took 6 g/day of Liupao tea fermented for one, four, seven, or ten years, respectively. The intervention lasted 90 days. Before and after the intervention, they were assessed for blood pressure, lipid and glucose levels, body weight and composition, and the gut microbiota profile.

Importantly, the study did not include a non-tea-drinking control group; all participants received some form of Liupao tea. The authors note this limitation, as it makes it harder to isolate the effects of tea alone. Additionally, participants were asked to maintain their usual diet and physical activity, but these factors were not objectively tracked, which could also influence results.

Study results

The study included 71 participants, with a mean age of 53.5. Most participants were female and had comparable educational, socioeconomic, drinking habits, and marital statuses.

Blood pressure

Post-intervention, all groups had lower systolic blood pressure. Significant reductions in systolic blood pressure were observed in the four-, seven-, and ten-year-aged groups, and diastolic blood pressure was significantly reduced in the ten-year-aged group.

Blood lipids

Blood cholesterol (total) dropped in the one-year group. This agrees with findings from earlier studies on black tea, where the likely mechanism involved endothelium-dependent vasodilation of the thoracic aorta and reduced smooth muscle cell contractility, which promoted vasodilation. However, the mechanism was not directly measured in the current trial; it is referenced from background research.

After the intervention, the one-, four-, and seven-year-old tea groups all showed significantly lower low-density lipoprotein (LDL) cholesterol. HDL cholesterol was increased in the groups that drank longer-aged tea (four and seven years).

Similar findings have been reported with other dark teas in metabolic syndrome patients. In animal studies, Liupao tea extracts at high doses reduced glucose levels, improved insulin sensitivity, and reduced blood cholesterol.

However, this study did not affect triglycerides or fasting blood glucose. This could be due to differences in bioavailability in the body compared to cell cultures, especially as in vitro methods employ alcohol extraction methods that increase the solubility of the bioactive compounds.

Body weight

As expected from prior studies, body weight reductions and body fat mass reductions were observed across groups, while muscle mass increased. Body composition did not vary with fermentation time. No signs of liver damage were observed, affirming its safety. Appetite scores also remained unchanged across groups.

Gut microbiota

Five phyla dominated the gut microbiota in these patients with metabolic syndrome. Firmicutes and Bacteroidota comprised 80% of the gut microbes. Post-intervention, their abundance fell across almost all groups. However, Bacteroidota abundance and the Firmicutes/Bacteroidota ratio decreased in the ten-year group.

Overall, Bacteroides was the single most abundant genus. Proteobacteria increased in all groups, as did Escherichia-Shigella, compared to the baseline. Despite comparable microbiota composition in all groups, microbial community structures were altered in all but the ten-year group.

These patterns corroborate prior studies that reported reduced inflammation and increased intestinal epithelial integrity with a reduced Firmicutes/Bacteroides ratio, maintaining a healthy gut microbiome. Dark teas were protective against irritable bowel syndrome in preclinical studies.

In the one-year group, a reduction in opportunistic pathogens like Stenotrophomonas and Rothia was observed, potentially reducing systemic inflammation. After the intervention, there was also enrichment of Eubacterium-halli-group, a short-chain fatty acid (SCFA)- producing bacterium, which may benefit the host in multiple ways. However, the study did not directly measure SCFA levels.

Microbial genera showed distinctive associations with metabolic markers across groups. In the one- and ten-year groups, the beneficial bacterium Akkermansia showed reduced abundance as the body mass index (BMI) rose. Others, like Subdioligranulum, decreased in abundance with rising triglyceride levels, perhaps because the latter inhibit triglyceride synthesis and improve insulin sensitivity. 

Lachnospiraceae, which regulates the reverse transport of cholesterol, was correlated with HDL cholesterol in four- and ten-year groups but negatively associated with body weight in the ten-year group. This may indicate that it plays a greater role in balancing energy in the latter group. The inference is that “LPT aged for different durations exerts targeted effects on metabolic indicators by shaping distinct gut microbiota compositions.”

While storage improves the flavor of Liupao tea, its chemical composition also changes, indicating the need for further studies to understand how various components affect human health.

The present study found no significant difference in metabolic effects between teas of different ages. Controlled trials should also explore the role of physical activity, diet, and time in the outcomes of various groups. More work is also needed on the pathways underlying their effects.

Conclusions

Consuming Liupao tea improves metabolic parameters and the gut microbiome profile in patients with metabolic syndrome, irrespective of the aging time. Stable liver function markers confirmed its safety, and its cost-effectiveness adds to the appeal of this natural drink as an aid to managing metabolic health. “These findings support LPT as a functional beverage for the management of MetS (metabolic syndrome).”

However, the lack of a non-tea control group and the absence of objective monitoring of participants' diet and activity mean that more rigorous studies are needed to confirm these findings and clarify causality.

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