Brown Adipose Tissue, Diet-Induced Thermogenesis, and Thermogenic Food Ingredients: From Mice to Men

Abstract

Since the recent rediscovery of brown adipose tissue (BAT) in adult humans, this thermogenic tissue has been attracting increasing interest. The inverse relationship between BAT activity and body fatness suggests that BAT, because of its energy dissipating activity, is protective against body fat accumulation. Cold exposure activates and recruits BAT, resulting in increased energy expenditure and decreased body fatness. The stimulatory effects of cold exposure are mediated through transient receptor potential (TRP) channels and the sympathetic nervous system (SNS). Most TRP members also function as chemesthetic receptors for various food ingredients, and indeed, agonists of TRP vanilloid 1 such as capsaicin and its analog capsinoids mimic the effects of cold exposure to decrease body fatness through the activation and recruitment of BAT. The antiobesity effect of other food ingredients including tea catechins may be attributable, at least in part, to the activation of the TRP-SNS-BAT axis. BAT is also involved in the facultative thermogenesis induced by meal intake, referred to as diet-induced thermogenesis (DIT), which is a significant component of the total energy expenditure in our daily lives. Emerging evidence suggests a crucial role for the SNS in BAT-associated DIT, particularly during the early phase, but several gut-derived humoral factors may also participate in meal-induced BAT activation. One intriguing factor is bile acids, which activate BAT directly through Takeda G-protein receptor 5 (TGR5) in brown adipocytes. Given the apparent beneficial effects of some TRP agonists and bile acids on whole-body substrate and energy metabolism, the TRP/TGR5-BAT axis represents a promising target for combating obesity and related metabolic disorders in humans.

Metabolic Impact of Flavonoids Consumption in Obesity: From Central to Peripheral

“…Global effects of flavanols in adipose tissues lead to a decrease in adiposity, specially of the WAT depots and in adipocyte size by reducing adipogenesis, the release of adipokines such as leptin and resistin, the modulation of lipid metabolism and the induction of browning [ 153 , 155 , 158 , 169 , 170 , 171 , 172 , 173 , 174 ]. In BAT, flavanols caused the activation of thermogenesis and FAO [ 172 , 173 , 174 , 175 , 176 ].…”

“…Different approaches have been done to demonstrate the effects of green tea extract and caffeine over thermogenesis and body weight [ 186 , 187 ]. Short- and long-term effects have been studied with different results and effectiveness but suggesting that catechins and caffeine may act synergistically to control body weight and induce thermogenesis [ 175 , 188 ]. It has been proposed that the thermogenic response to green tea extracts or its components would be mediated, in BAT, by the direct stimulation of the β-adrenergic receptor (β-AR) cascade through the inhibition of the enzyme catechol-O-methyl transferase (COMT), which degrades catecholamines.…”

“…It has been proposed that the thermogenic response to green tea extracts or its components would be mediated, in BAT, by the direct stimulation of the β-adrenergic receptor (β-AR) cascade through the inhibition of the enzyme catechol-O-methyl transferase (COMT), which degrades catecholamines. On its side, caffeine inhibited PDE, thus inducing a sustained activation of the PKA and its downstream cascade [ 175 ].…”

Combined extracts of Moringa oleifera, Murraya koeingii leaves, and Curcuma longa rhizome increases energy expenditure and controls obesity in high-fat diet-fed rats

“…Beige fat cells possess mixed physiological and morphological features of the brown fat cells. These metabolically active cells generate from WAT cells primarily through beta-adrenergic receptor activation in an autocrine, paracrine, or endocrine mechanism when exposed to cold or food ingredients [ 20 , 22 , 23 ]. The browning of WAT requires the active involvement of several metabolic factors that include adiponectin [ 12 , 13 , 24 ] and triiodothyronine (T3) [ 25 , 26 ].…”

Effects of beta-conglycinin intake on circulating FGF21 levels and brown adipose tissue activity in Japanese young men: a single intake study and a randomized controlled trial

“…It has been demonstrated that human BAT has beneficial effects on body composition and glucose metabolism, and the same is true for animals [1][2][3][4][5]. Previous studies have undertaken the strategy of increasing BAT activity through dietary intake activating the sympathetic nervous system [6,7]. It is therefore necessary to further elucidate the regulatory factors of human BAT activity.…”