Kaempferia parvifl ora Extract Increases Whole-Body Energy Expenditure in Humans : Roles of Brown Adipose Tissue

The prevalence of obesity and associated metabolic diseases such as diabetes mellitus and dyslipidemia has been increasing over the past few decades. The cause of weight gain is explained by a chronic imbalance between whole-body energy expenditure (EE) and energy intake. During the last decade much attention has been paid on the role of brown adipose tissue (BAT) in the control of whole-body EE and body fatness (1, 2). BAT is known as the major site of sympathetically activated thermogenesis during cold exposure and probably after spontaneous overfeeding in small rodents. BAT thermogenesis is totally dependent on the uncoupling protein 1 (UCP1), which has the activity of uncoupling oxidative phosphorylation from ATP synthesis, thereby dissipating energy as heat. Recent radionuclide imaging studies using fl uorodeoxyglucose (FDG)-positron emission tomography (PET) with computed tomography (CT) have revealed the existence of metabolically active BAT in adult human subjects (3–6). Human BAT is activated by acute cold exposure, being positively correlated to cold-induced thermogenesis (7–9). The activity and prevalence of cold-activated BAT are inversely related to body mass index (BMI), body fat and visceral fat (3–5, 10). Moreover, prolonged cold exposure recruits BAT in association with an increase in energy expenditure and decrease in body fat (9). It is thus likely that BAT contributes to the regulation of whole-body EE and body fatness in adult humans, as it does in small rodents. A number of food ingredients have been proposed as tools for increasing EE and decreasing body fat. One of these is capsaicin, the pungent ingredient of hot pepper, which activates the adreno-sympathetic nervous system and BAT, increases EE, and fat oxidation and reduces body fat (11, 12). Recently, we reported that nonpungent capsaicin analogues (capsinoids) increase EE through the activation of BAT in human subjects (13, 14). Kaempferia parvifl ora (KP) is a plant of the Zingiberaceae family indigenous to Thailand and Laos, where it has been used as a folk medicine to improve blood fl ow and increase vitality. KP was demonstrated to have some benefi cial effects such as stomach-protecting, anti-oxidant, and anti-infl ammatory effects (15–17). Moreover, it has been reported that dietary supplementation of rhizome powder of KP suppressed body weight increase, body fat accumulation, and glucose intolerance in obese type II diabtetic mice (18–20), suggesting anti-obesity effects of KP. As KP showed no notable effects on food intake, the observed anti-obesity effects may be attributable to increased EE. In line with this idea, Yoshino et al. demonstrated that KP ingestion increased urinary excretion of noradrenaline, UCP1 expression, and EE in Kaempferia parvifl ora Extract Increases Whole-Body Energy Expenditure in Humans: Roles of Brown Adipose Tissue