Photoperiod-dependent effects of (poly)phenol-rich extracts from seasonal fruits on the serum metabolome.

Seasonal rhythms are a recognised environmental factor affecting metabolism and health. In turn, phenolic compounds are recognised for their health-promoting properties and potential to influence biological rhythms. This work aimed to assess whether metabolic differences between seasons condition the response to dietary (poly)phenols. We exposed Fischer 344 male rats to short and long photoperiods simulating winter and summer, respectively. Eight different (poly)phenol-rich fruit extracts (FE) were administered, four obtained from spring-summer fruits and four of autumn-winter harvest fruits. A metabolomics-based approach was used for capturing systemic metabolic changes. Results showed a marked seasonal metabolic shift that conditions the response to FE. A common metabolic response to FE from autumn-winter fruits was identified accompanied by an anti-inflammatory pattern, suggesting that the effects were driven by shared seasonal characteristics of fruits rather than by the specific FE. Overall, (poly)phenols of seasonal fruits exert differential effects depending on the seasonally-conditioned metabolic state.