Prebiotic fiber may have a beneficial effect on the human’s microbiota. However, due to the lack of comprehensive food composition data (FCD), it is challenging to assess their dietary intake. The aim of present study is to quantify naturally occurring prebiotics, such as inulin-type fructans (ITFs), fructo-oligosacharides (FOSs), and galacto-oligosacharides (GOSs), in raw and processed Italian foods and to estimate their intake in a healthy population (N = 4154) belonging to an Italian case-control study on colorectal cancer. ITFs were determined using enzymatic method and high-performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). FOSs and GOSs were determined by alkaline hydrolysis and HPAEC-PAD. Garlic (25.1 g/100 g) and jerusalem artichoke (16.7 g/100 g) were the ITFs-richest foods. Jerusalem artichoke was also the richest in FOSs (4.45 g/100 g). GOSs were mainly detected in dry and canned pulses (0.01–2.04 g/100 g). In our population, the median intake of ITFs, FOSs and GOSs was 0.797, 0.187 and 0.283 g/day, respectively. Given the unclear definition of inulin due to the heterogenicity of methodologies, it was challenging to compare published prebiotic fiber’s FCD and use them in epidemiological research. Within the present work we produced novel FCD able to preliminary estimate the intake of prebiotic fiber.
