Glycaemic impact of tomato bioactive compounds: mechanisms, clinical evidence, and future directions

Tomatoes, a key element of the Mediterranean diet, are a rich source of bioactive compounds that contribute positively to health. This review investigates how interactions between starch and tomato polyphenols and carotenoids impact starch digestibility and the glycaemic response. A key focus is the role of the food matrix and nutrient interactions, often overlooked in studies assessing individual compounds. We found that bioactive compounds from tomatoes can modulate starch digestion at the molecular level, and that the interactions between starch and bioactive compounds depend on the starch structure, type of bioactive compound, and complexation conditions. However, results from intervention studies assessing the effect of tomato bioactive compounds on glycemia in humans are not convincing and modest or non-significant changes were observed in glucose and insulin concentrations. This may be due to the lack of specific studies on glycemia and the diverse study populations, which complicate direct comparisons of results. Overall, this review highlights the importance of analyzing how nutrient interactions and the food matrix influence nutrient digestibility and absorption. Furthermore, we identify research gaps regarding the effects of consuming tomatoes or tomato-based products alongside starch-based foods, emphasizing the need for further targeted studies to clarify their role in glycaemic regulation.