Vitamin A Derivatives and Adipose Tissue Differentiation: Molecular Pathways Driving Browning and Anti-Obesity Effects

This review aims to evaluate the effects of retinoids and carotenoids (β-carotene, lycopene, lutein, and β-cryptoxanthin) on adipose tissue biology, particularly browning processes, in light of the current literature. In the current era of increasing global obesity prevalence, understanding the potential regulatory roles of these lipophilic micronutrients in energy homeostasis and adipose tissue plasticity may contribute to the development of new nutrition-based or pharmacological strategies. The regulatory roles of vitamin A (VA) and carotenoids in adipose tissue metabolism have been intensively investigated in recent years. Current findings indicate that compounds such as retinoic acid, lycopene, β-cryptoxanthin, and zeaxanthin reduce adipogenesis and lipogenesis by suppressing the expression of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding protein alpha (C/EBPα), and sterol regulatory element-binding protein 1c (SREBP1-c) while increasing energy expenditure and promoting the browning of white adipose tissue through the activation of 5′-adenosine monophosphate-activated protein kinase (AMPK) and the upregulation of thermogenic genes such as uncoupling protein 1 (UCP1), PR domain containing 16 (PRDM16), and PPARγ coactivator-1α (PGC-1α). These effects are associated with reduced adipocyte hypertrophy, increased mitochondrial activity, and decreased systemic inflammation. VA and carotenoids exert multifaceted effects on adipose tissue differentiation and energy metabolism, suggesting an alternative pathway against obesity. By reducing lipid storage, stimulating thermogenesis, and enhancing oxidative metabolism, these bioactive compounds help restore metabolic balance. Overall, evidence indicates that VA derivatives and carotenoids, through adipose tissue browning and improved metabolic efficiency, represent promising nutrition-based strategies to combat obesity.