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Dietary intake and major food sources of polyphenols in people with type 2 diabetes: The TOSCA.IT Study

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Proper evaluation of polyphenols intake at the population level is a necessary step in order to establish possible associations with health outcomes. Available data are limited, and so far no study has been performed in people with diabetes. The aim of this work was to document the intake of polyphenols and their major food sources in a cohort of people with type 2 diabetes and in socio-demographic subgroups.


We studied 2573 men and women aged 50–75 years. Among others, anthropometry was measured by standard protocol and dietary habits were investigated by food frequency questionnaire (EPIC). The intake of polyphenols was evaluated using US Department of Agriculture and Phenol-Explorer databases.


The mean total polyphenol intake was 683.3 ± 5.8 mg/day. Non-alcoholic beverages represented the main food source of dietary polyphenols and provided 35.5% of total polyphenol intake, followed by fruits (23.0%), alcoholic beverages (14.0%), vegetables (12.4%), cereal products and tubers (4.6%), legumes (3.7%) and oils (2.1%); chocolate, cakes and nuts are negligible sources of polyphenols in this cohort. The two most important polyphenol classes contributing to the total intake were flavonoids (47.5%) and phenolic acids (47.4%). Polyphenol intake increased with age and education level and decreased with BMI; furthermore, in the northern regions of Italy, the polyphenol intake was slightly, but significantly higher than in the central or southern regions.


The study documents for the first time the intake of polyphenols and their main food sources in people with diabetes using validated and complete databases of the polyphenol content of food. Compared with published data, collected in people without diabetes, these results suggest a lower intake and a different pattern of intake in people with diabetes.

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The participation of the patients in the study is gratefully acknowledged. We thank all the investigators and the dietitians in the TOSCA.IT centers for their cooperation.


The study is supported by the Italian Medicines Agency (AIFA) within the Independent Drug Research Program—contract No. FARM6T9CET—and by Diabete Ricerca, the no profit Research Foundation of the Italian Diabetes Society. The funding agency played no role in the study design; in the collection, analysis and interpretation of data; in the writing of the manuscript; or in the decision to submit the manuscript for publication.

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Appendix: TOSCA.IT Study Group (in order of number of patients contributed)

Appendix: TOSCA.IT Study Group (in order of number of patients contributed)

Napoli—Università “Federico II”: Angela Albarosa Rivellese, Sara Cocozza, Stefania Auciello, Anna Amelia Turco; Verona—Ospedale Civile di Verona: Enzo Bonora, Massimo Cigolini, Isabella Pichiri, Corinna Brangani, Elena Tomasetto; Perugia—Università di Perugia: Gabriele Perriello, Alessia Timi; Catania—Ospedale Garibaldi-Nesima: Sebastiano Squatrito, Tiziana Sinagra, Sara Longhitano, Vanessa Tropea; Rimini—Ospedale Infermi di Rimini: Giorgio Ballardini, Anna Carla Babini, Raffaella Ripani; Massa Carrara—ASL 1 Massa Carrara SSD Diabetologia: Giovanna Gregori, Maria Dolci, Laura Bruselli, Isabella Salutini, Mary Mori, Fabio Baccetti; Padova—Complesso Socio-Sanitario ai Colli: Annunziata Lapolla, Giovanni Sartore, Silvia Burlina, Nino Cristiano Chilelli; Latina—Ospedale S. Maria Goretti di Latina: Raffaella Buzzetti, Chiara Venditti, Stella Potenziani, Angela Carlone; Palermo—Università degli Studi di Palermo: Aldo Galluzzo†, Carla Giordano, Vittoria Torregrossa; Chiavari (GE)—ASL Chiavarese: Laura Corsi, Giacomo Cuneo, Simona Corsi; Eboli (SA)—Distretto 64: Biagio Tizio, Gennaro Clemente; Potenza—Rete ASP—PotenzaVilla d’AgriLagonegro: Giuseppe Citro, Maria Natale, Vita Salvatore; Livorno—ASL 6 Livorno: Graziano Di Cianni, Emilia Lacaria, Laura Russo; L’Aquila—Ospedale San Salvatore: Rossella Iannarelli, Antonella De Gregorio, Filomena Sciarretta, Settimio D’Andrea; Atri (TE)—Ospedale di Atri: Valeria Montani, Emanuela Cannarsa, Katia Dolcetti; Genova—DIMIUniversità di Genova: Renzo Cordera, Laura Affinito Bonabello, Chiara Mazzucchelli; Chieri (TO)—ASL Torino 5: Carlo Bruno Giorda, Francesco Romeo, Caterina Bonetto; Lanciano (CH)—Presidio Ospedaliero di Lanciano: Daniela Antenucci, Maria Pompea Antonia Baldassarre, Livia Santarelli; Napoli—Azienda Ospedaliera Universitaria “Policlinico”: Ciro Iovine, Rossella Nappo, Ornella Ciano; Parma—AOU di Parma: Elisabetta Dall’Aglio, Giovanni Mancastroppa; Udine—SOC di Endocrinologia e Malattie del Metabolismo: Franco Grimaldi, Laura Tonutti; Ancona—INRCAIRCCS: Massimo Boemi, Federica D’Angelo; Roma—Ospedale Pertini: Sergio Leotta, Lucia Fontana; Roma—Policlinico di Tor Vergata: Davide Lauro, Maria Elena Rinaldi; Foggia—OORR di Foggia: Mauro Cignarelli, Olga La Macchia, Stefania Fariello; Ferrara—Arcispedale “S. Anna”: Franco Tomasi, Chiara Zamboni, Nicoletta Dozio; Bergamo—Azienda Ospedaliera Papa Giovanni XXIII: Roberto Trevisan, Cristiana Scaranna; Pisa—Ospedale di Cisanello: Stefano Del Prato, Roberto Miccoli, Cristina Bianchi, Monia Garofolo; Roma—Azienda Ospedaliera S. Andrea: Giuseppe Pugliese, Laura Salvi, Graziela Rangel, Martina Vitale; Pistoia—UO di Diabetologia USL 3 Pistoia: Roberto Anichini, Anna Tedeschi, Elisa Corsini; Messina—Policlinico G. Martino: Domenico Cucinotta, Antonino Di Benedetto, Loretta Giunta, Maria Concetta Ruffo; Treviglio—Ospedale di Treviglio: Antonio Carlo Bossi, Rita Carpinteri; Siena—Policlinico “Le Scotte”: Francesco Dotta, Elena Ceccarelli; Ravenna—Ospedale Santa Maria Delle Croci: Paolo Di Bartolo, Chiara Caselli, Alessandra Luberto; Cesena—Ospedale M. Bufalini: Costanza Santini, Arianna Mazzotti, Giovanni Calbucci; Pescara—Ospedale Civile di Pescara: Agostino Consoli, Federica Ginestra; Prato—Ospedale di Prato: Maria Calabrese, Alessia Zogheri; Arezzo—Ospedale San Donato: Lucia Ricci; Bari—Policlinico Consorziale: Francesco Giorgino, Luigi Laviola, Claudia Ippolito, Lucia Tarantino; Padova—Policlinico di Padova: Angelo Avogaro, Monica Vedovato; Catanzaro—”Università Magna Graecia”: Agostino Gnasso, Claudio Carallo, Caterina Scicchitano; Piacenza—Ospedale Guglielmo da Saliceto: Donatella Zavaroni, Stefania Livraga; Torino—Ospedale Molinette di Torino: Paolo Cavallo Perin, Paolo Fornengo, Tania Prinzis; San Giovanni Rotondo—Ospedale Casa Sollievo della Sofferenza: Salvatore De Cosmo, Antonio Pio Palena, Simonetta Bacci; Firenze—Ospedale CareggiPontenuovo: Edoardo Mannucci, Caterina Lamanna; Messina—Ospedali Riuniti PapardoPiemonte di Messina: Pietro Pata, Gabriele Lettina; Campobasso—Presidio Ospedaliero A.S.RE. Molise: Antimo Aiello, Angelina Barrea; Spoleto—Ospedale San Matteo degli Infermi: Carlo Lalli, Maura Scarponi; Gallarate (VA)—Azienda Ospedaliera “ S. Antonio Abate” di Gallarate: Ivano Franzetti, Raffaella Radin; Lecce—Poliambulatorio Cittadella della Salute: Rosalia Serra, Francesca Petrachi; Cosenza—Azienda Sanitaria Provinciale (Distretti di Castrovillari, Diamante e Scalea): Vincenzo Asprino; Verona—Ospedale Civile “G. Fracastoro” di San Bonifacio: Claudio Capra, Massimo Cigolini; Terracina (LT)—Polo Sud ASL di Latina: Elisa Forte, Stella Potenziani; Bologna—Policlinico S. Orsola Malpighi: Giulio Marchesini Reggiani, Gabriele Forlani, Luca Montesi, Natalia Mazzella; Milano—Istituto Scientifico San Raffaele: Pier Marco Piatti, Lucilla Monti, Michela Stuccillo; Napoli—ASL NA2in cooperazione con Università “Federico II” di Napoli: Pasquale Auletta, Ettore Petraroli, Giuseppe Capobianco; Napoli—ASL NA3—in cooperazione con Università “Federico II” di Napoli: Geremia Romano, Michele Cutolo, Giosetta De Simone, Gennaro Caiazzo, Peppe Nunziata, Susy Sorrentino; Salerno—ASL di Salerno in cooperazione con Università di Napoli “Federico II”: Umberto Amelia, Pasqualino Calatola, Gelsomina Capuano.

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Vitale, M., Masulli, M., Rivellese, A.A. et al. Dietary intake and major food sources of polyphenols in people with type 2 diabetes: The TOSCA.IT Study. Eur J Nutr 57, 679–688 (2018).

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