Activation of brown adipose tissue by acute and chronic administrations of capsinoids in humans

Abstract

ObjectiveCapsinoids, nonpungent capsaicin‐related substances, are known to increase brown adipose tissue (BAT) thermogenesis and whole‐body energy expenditure (EE), and reduce body fat in small rodents. The objective of this study was to clarify whether BAT is involved in the thermogenic effects of capsinoids in humans.ResultsEighteen male volunteers underwent fluorodeoxyglucose‐ positron emission tomography after 2‐h cold exposure at 19 °C, and were divided into BAT‐positive and ‐ negative groups. Thermogenic responses to orally ingested capsinoids (9mg) or placebo were examined by indirect calorimetry at 27 °C. Thermogenic responses to cold at 19 °C (CIT) were also examined before and after daily ingestion of capsinoids for 6 weeks.ResultsOral ingestion of capsinoids increased EE in 1 h by 15.2 ± 2.6 kJ/h in the BAT‐positive group, more than in the BAT‐negative group (1.7 ± 3.8 kJ/h). Placebo ingestion produced no significant change in either group. CIT in the BAT‐negative group was much lower than that in the BAT‐positive group, but it increased after 6‐week capsinoids ingestion.ConclutionsOral ingestion of capsinoids increases EE by stimulating and recruiting BAT in humans.