The Role and Regulatory Mechanism of Brown Adipose Tissue Activation in Diet-Induced Thermogenesis in Health and Diseases

Abstract

Brown adipose tissue (BAT) has been considered a vital organ in response to non-shivering adaptive thermogenesis, which could be activated during cold exposure through the sympathetic nervous system (SNS) or under postprandial conditions contributing to diet-induced thermogenesis (DIT). Humans prefer to live within their thermal comfort or neutral zone with minimal energy expenditure created by wearing clothing, making shelters, or using an air conditioner to regulate their ambient temperature; thereby, DIT would become an important mechanism to counter-regulate energy intake and lipid accumulation. In addition, there has been a long interest in the intriguing possibility that a defect in DIT predisposes one to obesity and other metabolic diseases. Due to the recent advances in methodology to evaluate the functional activity of BAT and DIT, this updated review will focus on the role and regulatory mechanism of BAT biology in DIT in health and diseases and whether these mechanisms are applicable to humans.

Keywords: brown adipose tissue; diet-induced thermogenesis.

Figure 1

The role and regulatory mechanism of BAT activation in DIT in health and diseases. (A) Under healthy condition, dietary intake could promote BAT activation (facultative DIT) and total DIT to facilitate whole-body energy metabolism. (B) Under disease conditions: (1) Metabolic abnormalities such as obesity, diabetes, hyperlipidemia and NAFLD, dietary intake-induced BAT activation, and total DIT will be attenuated and might subsequently, affect whole-body energy balance and weight control. (2) Cancer-associated Cachexia (CAC) is characterized by systemic inflammation, which could enhance thermogenesis in BAT and increase systemic energy expenditure. However, low DIT were noted in the development of cancer cachexia.