Validation of the Fermented Food Frequency Questionnaire (3FQ) to assess consumption across four European regions: a study within the Promoting Innovation of ferMENTed fOods COST Action

Emmanouella Magriplis^1*Theodoros Smiliotopoulos¹Niki Myrintzou¹Kathryn Jane Burton-Pimentel²Signe Adamberg³Kaarel Adamberg³Duygu Ağagündüz⁴Natalija Atanasova-Pancevska⁵Meline Beglaryan⁶Elske M. Brouwer-Brolsma⁷Johanna Burtscher⁸Marija Cerjak⁹Zuzana Ciesarová¹⁰Inga Ciprovica¹¹Francesca De Filippis¹²Mónica Gandía¹³Elaine Hillesheim²Luziana Hoxha¹⁴Daniel Borch Ibsen¹⁵Nastia Ivanova¹⁶Håvard Jenssen¹⁷Petra Jones¹⁸Anastasia Kalea¹⁹Begüm Kalyoncu Atasoy²⁰Vaida Kitrytė-Syrpa²¹Aleksandar Ž. Kostic²²Marta Laranjo²³Victoria Meslier²⁴Nóra Emilia Nagybákay²⁵Gjore Nakov¹⁶Malviina Nikola²⁶Christos Pafilas¹Photis Papademas²⁷Foteini Pavli¹⁸Tagli Pitsi²⁸Terhi Pohjanheimo²⁹Igor Pravst³⁰Jelena Rajic³¹Pasquale Russo³²Taner Sar³³Małgorzata Starowicz³⁴Irzada Taljic³⁵Biljana Trajkovska³⁶Guy Vergères²Bojana B Vidovic³¹Christophe Chassard²⁴Michail Syrpas^21*

• ¹Laboratory of Dietetics and Quality of Life, Department of Food Science & Human Nutrition, Agricultural University of Athens, Athens, Greece
• ²Agroscope, Food Microbial Systems Research Division, Bern, Switzerland
• ³Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
• ⁴Department of Nutrition and Dietetics, Gazi University, Emek, Ankara 06490, Türkiye
• ⁵Ss. Cyril and Methodius University in Skopje, Faculty of Natural Sciences and Mathematics – Skopje, Institute of Biology, Department of Microbiology and Microbial Biotechnology, Skopje, North Macedonia
• ⁶Center for Ecological-Noosphere Studies, National Academy of Sciences of the Republic of Armenia (NAS RA), 68 Abovyan str., 0025 Yerevan, Armenia
• ⁷Division of Human Nutrition and Health, Wageningen University & Research, 6700AA, Wageningen, Netherlands
• ⁸University of Natural Resources and Life Sciences, Vienna, Department of Food Science and Technology, Institute of Food Science, 1190 Vienna, Austria
• ⁹Faculty of Agriculture, University of Zagreb, Zagreb, Croatia
• ¹⁰National Agricultural and Food Centre, Food Research Institute, Bratislava, Slovakia
• ¹¹Latvia University of Life Sciences and Technologies, Jelgava, Latvia
• ¹²Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
• ¹³Food Technology Area, Preventive Medicine and Public Health, Food Science, Toxicology and Forensic Medicine Department. Faculty of Pharmacy and Food Sciences, University of Valencia, Valencia, Spain
• ¹⁴Faculty of Biotechnology and Food, Agrriculture University of Tirana, Str. Pajsi Vodica, 1029 Tirana, Albania
• ¹⁵Department of Public Health, Aarhus University, Bartholins Allé 2, 8000 Aarhus C, Denmark
• ¹⁶College of Sliven, Technical University of Sofia, 8800 Sliven, Bulgaria
• ¹⁷a Department of Chemistry, University of Oslo, Oslo, Norway;b Department of Science and Environment, Roskilde University, Roskilde, Denmark
• ¹⁸Department of Food Sciences and Nutrition, Faculty of Health Sciences, University of Malta, Msida, Malta
• ¹⁹Division of Medicine, University College London, London, United Kingdom
• ²⁰University of Health Sciences, Gulhane Health Sciences Faculty, Department of Nutrition and Dietetics, Ankara, Türkiye
• ²¹Department of Food Science and Technology, Kaunas University of Technology, 50254 Kaunas, Lithuania
• ²²Department of Food Technology and Biochemistry, Faculty of Agriculture, University of Belgrade, Belgrade, Serbia
• ²³MED – Mediterranean Institute for Agriculture, Environment and Development & CHANGE – Global Change and Sustainability Institute,  Escola de Ciências e Tecnologia, Universidade de Évora, Évora, Portugal
• ²⁴Université Paris-Saclay, INRAE, MetaGenoPolis, 78350 Jouy-en-Josas, France
• ²⁵Department of Food Science and Technology, Kaunas University of Technology, Radvilėnų Rd. 19, 50254 Kaunas, Lithuania
• ²⁶Aistila Ltd., 20520 Turku, Finland
• ²⁷Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, Limassol, Cyprus
• ²⁸1) Department of Chemistry and Biotchnology, Tallinn University of Technology; 2) Department of Nutrition and Exercise, The National Institute of Health Development, Tallinn, Estonia
• ²⁹Aistila Ltd, 20520 Turku, Finland
• ³⁰Institute of Nutrition, Koprska ulica 98, 1000 Ljubljana, Slovenia
• ³¹Department of Bromatology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
• ³²Department of Food, Environmental and Nutritional Science (DeFENS), University of Milan, 20133 Milan, Italy
• ³³Swedish Centre for Resource Recovery, University of Borås, Borås 501 90, Sweden
• ³⁴Team of Chemistry and Biodynamics of Food, Institute of Animal Reproduction and Food Research, 10-683 Olsztyn, Poland
• ³⁵University of Sarajevo, Faculty of Agriculture and Food Sciences, 71000 Sarajevo, Bosnia and Herzegovina
• ³⁶Faculty of Biotechnical Sciences, University st. Kliment Ohridski, Bitola, North Macedonia

Background: Fermented foods are an integral part of diets worldwide, and emerging epidemiological data suggest their significant beneficial health effects. However, assessing their intake is challenging since many of these foods are sporadically and/or locally consumed, hence current traditional nutritional assessment tools lack the specificity to capture this variability. To address this gap, the Fermented Food Frequency Questionnaire (3FQ) was developed and this study aimed to evaluate its relative validity and repeatability across European regions. Methods: In the validation study of the 3FQ, 12,646 adult participants were recruited across four European regions to assess consumption of sixteen major fermented food groups. Repeatability was assessed by administering the 3FQ twice, approximately six weeks apart, to a subset of participants (n=2315). Validity was evaluated using 24-hour dietary recalls (24hR). Statistical analyses included Spearman's rank correlation coefficients and Intra-Class Correlation coefficients (ICC) for repeatability, and Bland-Altman plots for validity. Results: Results showed high repeatability, overall and by region, for estimated quantities and frequencies of consumption for most of the fermented food groups (from 0.4 to 1.0), with a few exceptions for infrequently consumed items (e.g., fermented fish). Validity assessment via Bland-Altman plots revealed excellent agreement between the 3FQ and 24hR for most of the food groups, with over 90% of values falling within the agreement interval. Notably, fermented dairy products, coffee, and bread categories showed the strongest agreement (>95%). Conclusion: The 3FQ is a robust and reliable tool for estimating the consumption of diverse fermented food groups across four European regions and provides valid estimates of the frequency and quantity of intake for specific fermented foods. The 3FQ could be a valuable instrument for epidemiological research aiming to elucidate associations between certain fermented foods and health parameters in European diets.