Goishi tea leaf powder affects lower body weight and visceral fat accumulation during energy restriction in obese rats.

Goishi tea is a unique Japanese post-fermented tea produced in Kochi prefecture. The aim of this study was to investigate whether the supplementation of energy-restricted diet with Goishi tea leaves affects body weight, visceral fat accumulation, and fecal lipids in diet-induced obese rats. 18 male Wistar rats were fed a high-fat diet for 12 weeks. Subsequently, the diet-induced obese rats were fed a low-energy diet containing 1% (G1 group) or 3% (G3 group) of Goishi tea leaf powder, or without any tea extracts (C group) for 4 weeks. After 4 weeks, body weight and body fat ratio were significantly lower in the G3 group than in the C group. Plasma insulin levels were significantly higher in the C group than in the G1 and G3 groups, whereas plasma leptin levels were significantly lower in the G3 group than in the C group. In addition, the lipid absorption rate was significantly lower in the G3 group than in the C and G1 groups. In conclusion, the administration of Goishi tea leaves under dietary restrictions might contribute to body weight reduction and inhibition of lipid absorption, as a diet therapy to help prevent obesity and metabolic syndrome. J. Med. Invest. 70 : 60-65, February, 2023.

Awa (Tokushima) lactate-fermented tea as well as green tea enhance the effect of diet restriction on obesity in rats.

Drinking tea is recommended for promoting health due to its bioactive nutrients, such as catechins and caffeine. In Tokushima area, we have a unique traditional tea, named Awa tea, which are fermented with Lactobacillus pentosus and Lactobacillus plantarum. The present study was designed to investigate anti-obesity effects of the Awa tea and compare with those of non-fermented green tea. Obese male Wistar rats (19 weeks of age) were given by low energy diets containing 3% of Awa and green tea extracts, respectively, or without any tea extracts (control), for 4 weeks. Awa tea contained smaller amount of catechins than green tea, although they contained similar amounts of polyphenols. This finding indicates that there are distinct kinds of polyphenols from catechins. The diets containing Awa and green tea extracts further decreased whole body weight, fat tissue mass and plasma leptin level, compared with control diet. In addition, their diets increased the daily amount of lipid excreted to feces and total 24-h-energy consumption, compared with the control group. However, there is no significant difference in these anti-obesity effects between Awa tea and green tea. Our results indicate that Awa lactate-fermented tea as well as green tea similarly enhance the effect of diet restriction on obesity, at least in part, through the increase in fat energy consumption and the decrease in fat absorption in rats.