Plant Foods as Healthy Sources of Dietary Fibre, Microbiota Modulation and Bioactive Compounds: Beyond Definitions—A Review

Dietary fibre (DF) and bioactive compounds (BCs) are essential components of a healthy diet and are abundant in plant-rich dietary patterns. Increasing evidence demonstrates that their combined and synergistic actions significantly influence human health, largely through their effects on the gut microbiota. This review highlights the need for more precise terminology regarding DF and BCs, as inconsistent use of these terms can create confusion among both consumers and researchers. The DF complex encompasses all non-digestible food components that have a positive effect on human health, together with the BCs associated with them, recognising that DF often serves as a carrier for these compounds throughout the digestive tract. Although recommended intakes for BCs have not been established, intake levels observed in populations adhering to healthy dietary patterns may serve as useful reference points. Updated data on the intake and estimated intestinal bioaccessibility of polyphenolic compounds in the contemporary Spanish diet are presented.