Brown adipose tissue (BAT) is responsible for cold-and diet-induced thermogenesis, and thereby contributes to the control of whole-body energy expenditure (EE) and body fat content. BAT activity can be assessed by fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) in human subjects. Grains of paradise (GP, Aframomum melegueta), a species of the ginger family, contain pungent, aromatic ketones such as 6-paradol, 6-gingerol and 6-shogaol. An alcohol extract of GP seeds and 6-paradol are known to activate BAT thermogenesis in small rodents. The present study aimed to examine the effects of the GP extract on whole-body EE and to analyse its relation to BAT activity in men. A total of nineteen healthy male volunteers aged 20-32 years underwent FDG-PET after 2 h of exposure to cold at 198C with light clothing. A total of twelve subjects showed marked FDG uptake into the adipose tissue of the supraclavicular and paraspinal regions (BAT positive). The remaining seven showed no detectable uptake (BAT negative). Within 4 weeks after the FDG-PET examination, whole-body EE was measured at 278C before and after oral ingestion of GP extract (40 mg) in a single-blind, randomised, placebocontrolled, crossover design. The resting EE of the BAT-positive group did not differ from that of the BAT-negative group. After GP extract ingestion, the EE of the BAT-positive group increased within 2 h to a significantly greater (P,0·01) level than that of the BAT-negative group. Placebo ingestion produced no significant change in EE. These results suggest that oral ingestion of GP extract increases wholebody EE through the activation of BAT in human subjects.Key words: Grains of paradise: 6-Paradol: Brown adipose tissue: Energy expenditure Brown adipose tissue (BAT) is the major site for sympathetically activated thermogenesis during cold exposure and spontaneous overfeeding, at least in small rodents (1) . Recent studies using fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) combined with computed tomography (CT) have revealed the existence of metabolically active BAT in adult human subjects (2 -4) . It is now established that, in healthy adults, BAT is activated by acute cold exposure and significantly contributes to cold-induced thermogenesis (2 -5) . It has also been demonstrated that the prevalence and activity of BAT are lower in subjects with higher adiposity, being negatively correlated with BMI, body fat content and visceral fat (2,3) . Moreover we found that the prevalence of BAT decreased with age, being more than 50 % in the twenties, but less than 10 % in the fifties and sixties, and that decreased BAT activity is associated with age-related accumulation of body fat (6) . It is thus likely that BAT, based on its thermogenic activity, contributes to the control of whole-body energy expenditure (EE) and body fat metabolism in human subjects, as established in small rodents, and thereby is a promising target for interventions to prevent and treat obesity. A number of food ingredients have been p...

The increase of whole-body energy expenditure seen after a single meal ingestion, referred to as diet-induced thermogenesis (DIT), substantially varies depending on the meal’s macronutrient composition. Brown adipose tissue (BAT), a site of non-shivering thermogenesis, was reported to be involved in DIT. To examine the effects of meal composition on BAT-associated DIT in humans, healthy male participants underwent fluorodeoxyglucose–positron emission tomography to assess BAT activity, and respiratory gas analysis for 2 h after ingestion of a carbohydrate-, protein-, or fat-rich meal (C-meal, P-meal, and F-meal, respectively). The calculated DIT at 2 h was 6.44 ± 2.01%, 3.49 ± 2.00%, and 2.32 ± 0.90% of the ingested energy after the P-meal, C-meal, and F-meal, respectively. The DIT after C-meal ingestion correlated positively with BAT activity (P = 0.011), and was approximately twice greater in the group with high-BAT activity than in the group with low-BAT activity (4.35 ± 1.74% vs. 2.12 ± 1.76%, P < 0.035). Conversely, the DIT after F-meal or P-meal ingestion did not correlate with BAT activity, with no difference between the two groups. Thus, BAT has a significant role in DIT after ingestion of a carbohydrate-rich meal, but hardly after ingestion either protein- or fat-rich meal.