Vitis vinifera L. Bioactive Components Modulate Adipose Tissue Metabolic Markers of Healthy Rats in a Photoperiod‐Dependent Manner

Scope The beneficial health effects of (poly)phenol‐rich foods such as red grapes mainly depend on both the type and concentration of (poly)phenols. Since fruit (poly)phenol content is influenced by growing conditions, the study examines the seasonal effects of red grapes (Vitis vinifera L.), grown under various cultivation conditions, on metabolic markers of adipose tissue in healthy rats. Methods and results For this purpose, Fischer 344 rats are exposed into three different light‐dark cycles and daily supplemented with 100 mg kg−1 of either conventionally or organically grown red grapes for 10 weeks (n = 6). Seasonal consumption of organic grapes (OGs), which are richer in anthocyanins, increases energy expenditure (EE) of animals exposed to long photoperiod and enhances uncoupling protein 1 (UCP1) protein expression in brown adipose tissue of animals under standard photoperiod. Additionally, red grape consumption affects the gene expression profile of white adipose tissue (WAT), upregulating browning markers of subcutaneous WAT in 12 h light (L12) and 18 h light (L18) photoperiods, and downregulating adipogenic and lipolytic markers of visceral WAT in 6 h light (L6) and L12 photoperiods. Conclusions These results clearly show that bioactive compounds of grapes can modulate the metabolic markers of white and brown adipose tissues in a photoperiod and depot‐dependent manner, partly affecting EE when consumed out of season. This study aims to describe the metabolic effects of seasonal consumption of red grapes as a rich and natural source of (poly)phenols. Specifically, it focuses on energy metabolism and the biology of the adipose tissue, a key player in the energy balance regulation in mammals. Moreover, it highlights that differences in (poly)phenol composition in one same fruit, resulting from distinct growing conditions, can also affect metabolism.