Mouse study supports development of functional compound dark teas
“Our results suggest that low- and high-concentrations of CDT could reduce body weight by 15 and 16% and by 44 and 38% of body fat, respectively, by attenuating body weight gain and fat accumulation, improving glucose tolerance, alleviating metabolic endotoxemia and regulating the mRNA expression levels of lipid metabolism-related genes,” they wrote in the journal Frontiers in Nutrition.
The study was supported by the Special Funds for Construction of Innovative Provinces in the Hunan Province. One author on the study was affiliated with Hunan Chu Ming Tea Industry Co. and is the first named inventor on the CDT patent.
Compound dark tea
The researchers note that dark tea has been linked to multiple health benefits, including anti-inflammatory, antioxidant, lipid-lowering and anti-obesity effects, thanks to its rich polysaccharide, polyphenol and alkaloid content.
“Dark tea is a fermented tea that plays a role in regulating the homeostasis of intestinal microorganisms,” they added, acknowledging the “important links between gut microbiota and diseases such as diabetes, non-alcoholic fatty liver disease and obesity.”
Used for centuries in traditional Chinese medicine, its bitterness has kept it out of the mainstream, but new blends are moving dark tea from niche into China’s booming “new-style” tea (think bubble tea) market fueled by young consumers in search of innovative beverages with enhanced health benefits.
In this study, the researchers evaluated the effects of a novel CDT developed to improve the taste and anti-obesity effects of dark tea. The preparation included a blend of 50% Fu brick and 10% Kuding dark teas, 25% green tea and 15% monk fruit (Momordica grosvenori) sweetener, all purchased from the Hunan Chu Ming Tea Industry Co.
The study randomly assigned 36 six-week-old male C57BL/6J mice to one of four equal groups: the common diet group, high-fat diet group, a high-fat diet/low-concentration (6 mg/mL) CDT group and a high-fat diet/high-concentration (12 mg/mL) CDT group.
Over an 18-week test period, mice consumed the CDT out of sterile plastic bottles that were replaced with fresh low- or high-concentration tea every two days. Any surplus was collected and measured. All the mice had ad libitum access to food and water.
The study assessed food consumption and body weight once a week and anesthetized the mice at the end of the experiment to freeze their cecum contents, liver, serum and perirenal, epididymal, subcutaneous and brown adipose tissues for follow-up analysis.
“Consistent with previous studies, mice fed a HFD for 18 weeks demonstrated that CDT had lipid-lowering and anti-obesity effects,” the researchers wrote. They highlighted that low-concentrations of CDT had a greater effect than high-concentrations in preventing obesity – increasing the abundance of beneficial Ruminococcus bacteria and reducing the abundance of harmful Desulfovibrio bacteria in the intestine of high-fat diet-fed mice.
“This study suggests that CDT can significantly ameliorate lipid metabolism in mice and opens new avenues for the development of functional compound tea drinks,” the researchers concluded.
Source: Frontiers in Nutrition
“Compound dark tea ameliorates obesity and hepatic steatosis and modulates the gut microbiota in mice”
Authors: Jianyu Qu et al.