Flavonoids’ Dual Benefits in Gastrointestinal Cancer and Diabetes: A Potential Treatment on the Horizon?

SIMPLE SUMMARY: The consumption of flavonoids positively influences the same (impaired) metabolic pathways in diabetes and gastrointestinal cancers, leading to the hypothesis that flavonoids could exert dual effects on these diseases, as some flavonoids can target the same pathways in both conditions, such as the apoptosis and AMPK pathways. Here, we identified flavonoids with such interactions and discussed their positive effects on both diseases. Nevertheless, more efforts are required to estimate the appropriate flavonoid dosage and flavonoid–flavonoid interactions, and to identify potential side effects. It is also necessary to assess the possibility of combining multiple flavonoids with the currently used treatment. ABSTRACT: Diabetes and gastrointestinal cancers (GI) are global health conditions with a massive burden on patients’ lives worldwide. The development of both conditions is influenced by several factors, such as diet, genetics, environment, and infection, which shows a potential link between them. Flavonoids are naturally occurring phenolic compounds present in fruits and vegetables. Once ingested, unabsorbed flavonoids reaching the colon undergo enzymatic modification by the gut microbiome to facilitate absorption and produce ring fission products. The metabolized flavonoids exert antidiabetic and anti-GI cancer properties, targeting major impaired pathways such as apoptosis and cellular proliferation in both conditions, suggesting the potentially dual effects of flavonoids on diabetes and GI cancers. This review summarizes the current knowledge on the impact of flavonoids on diabetes and GI cancers in four significant pathways. It also addresses the synergistic effects of selected flavonoids on both conditions. While this is an intriguing approach, more studies are required to better understand the mechanism of how flavonoids can influence the same impaired pathways with different outcomes depending on the disease.