A scoping review on the health effects of fermented foods in specific human populations and potential use of fermented foods in precision nutrition: knowledge and gaps

Christèle Humblot¹Panagiota Alvanoudi²Emilia Alves³Ricardo Assunção⁴Miona Belović⁵Tugce Bulmus Tuccar⁶Christophe Chassard^7,8Muriel Derrien⁹Mustafa Fevzi KARAGÖZ¹⁰Sibel Karakaya¹¹Marta Laranjo¹²FANI Th MANTZOURIDOU²Catarina Rosado¹³Smilja Praćer¹⁴Helen Saar¹⁵Julien Tap¹⁶Primož Treven¹⁷Guy Vergères¹⁸Eugenia Pertziger¹⁸Isabelle Savary-Auzeloux^19,20*

• ¹Institut de recherche pour le developpement, Marseille, France
• ²Aristoteleio Panepistemio Thessalonikes, Thessaloniki, Greece
• ³Universidade Lusófona,, lisboa, Portugal
• ⁴Instituto Universitario Egas Moniz Centro de Investigacao Interdisciplinar Egas Moniz, Caparica, Portugal
• ⁵University of Novi Sad, Institute of Food Technology, Novi Sad, Serbia
• ⁶Yuksek Ihtisas Universitesi, Ankara, Türkiye
• ⁷Institut national de recherche pour l'agriculture l'alimentation et l'environnement, Paris, France
• ⁸UMR Fromages, Aurillac, France
• ⁹KU Leuven, VIB-Center of Microbiology, Leuven, Belgium
• ¹⁰Hitit Universitesi, Çorum, Türkiye
• ¹¹Ege Universitesi, Izmir, Türkiye
• ¹²Instituto Mediterraneo para a Agricultura Ambiente e Desenvolvimento, Evora, Portugal
• ¹³Universidade Lusófona, Lisboa, Portugal
• ¹⁴Univerzitet u Beogradu Institut za bioloska istrazivanja Sinisa Stankovic, Belgrade, Serbia
• ¹⁵AS TFTAK, Tallinn, Estonia
• ¹⁶Microbiologie de l'Alimentation au Service de la Sante, Jouy-en-Josas, France
• ¹⁷Univerza v Ljubljani, Ljubljana, Slovenia
• ¹⁸Agroscope, Bern, Switzerland
• ¹⁹Institut National de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE), Paris, France
• ²⁰Unite de Nutrition Humaine, Saint-Genès-Champanelle, France

Background: Diets and specific foods affect health, and inter-individual response to nutritional factors are observed. This uman variability can be considered as a basis for developing personalised/precision nutrition. Fermented foods (FF) contain a wide range of macro- and micronutrients, bioactive compounds and a source of live or dead microorganisms. FF represent a large variety of products and have received significant interest for their potential health benefits. However, consistent evidence remains limited, possibly due to heterogeneity in individual responses. Objectives: The objective of the review is to assess and compile existing evidence of variable response of populations to FF and consequently whether FF could be integrated in a precision nutrition strategy. Design: Interventional and observational human studies were collected systematically. The publication identified the main factors likely to contribute to a variable response to FF across all health outcomes. The question was systematically addressed to assess the available evidence and identify knowledge gaps to focus future research. A pragmatic approach was the use of EFSA health claim guidelines, which requires an assessment of the food characteristics and of the mechanisms of action, in addition to the systematic search of human interventional studies. A similar approach was used for the analysis of the data extracted from the observational studies. Population included all human (healthy, non-healthy, all ages) observational and interventional studies. Intervention consisted on the ingestion of any FF. Control was the absence or a lower consumption of FF, or a corresponding non-FF. Outcome included all markers of the population’s health status. Results: The main factors contributing to the variable response to FF across all health outcomes were related to the initial phenotypic characteristics (biological sex, geographical origin, hormonal status, age), health status at baseline (metabolic syndrome (MetS), chronic metabolic pathologies, cancer, psychological disorders) and genetic background. Additionally, as gut microbiota is person-specific, and a factor determining variable metabolic response, a particular focus was given to the functions of gut microbiota and their role in the variability of population responses to FF. Conclusion: Collectively, this review represents a first step towards evaluating the feasibility of using FF in tailored nutritional strategies.