Bioactive Compounds in Fermented Foods: A Systematic Narrative Review

İbrahim Ender Künili^1*Vildan Akdeniz²Aslı Akpınar³Şebnem Öztürkoğlu Budak⁴José Antonio Curiel⁵Mustafa Guzel⁶Cem Karagözlü²Muzeyyen Berkel Kasikci⁷MARIO CARUANA GRECH PERRY⁸Małgorzata Starowicz⁹Christèle Humblot¹⁰Erhan Keyvan¹¹Christophe Chassard¹²Smilja Todorović¹³Guy Vergères¹⁴Harun KESENKAŞ^2*

• ¹Faculty of Marine Sciences and Technology, Çanakkale Onsekiz Mart University, Çanakkale, Türkiye
• ²Department of Dairy Technology, Faculty of Agriculture, Ege University, Izmir, Türkiye
• ³Department of Food Engineering, Manisa Celal Bayar University, Manisa, Türkiye
• ⁴Department of Dairy Technology, Faculty of Agriculture Ankara University, Ankara, Türkiye
• ⁵Food Technology Department, National Institute for Agricultural and Food Research and Technology (INIA-CSIC), Madrid, Spain
• ⁶Department of Food Engineering, Hitit University, Corum, Türkiye
• ⁷Department of Food Engineering, Faculty of Engineering and Natural Science, Manisa Celal Bayar University, Manisa, Türkiye
• ⁸Faculty of Health Sciences, University of Malta, Msida, Malta
• ⁹Department of Chemistry and Biodynamics of Food, Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Olsztyn, Poland
• ¹⁰French National Research Institute for Sustainable Development (IRD), Montpellier, France
• ¹¹Burdur Mehmet Akif Ersoy University, Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, Burdur, Türkiye
• ¹²Human Nutrition Unit, INRAE, Université Clermont-Auvergne, Clermont-Ferrand, France
• ¹³Institute for Biological Research Sinisa Stankovic, National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
• ¹⁴Research Division Microbial Food Systems, Agroscope, Berne, Switzerland

This systematic narrative review aims to catalogue bioactive compounds that are formed during the fermentation process and identified as contributors to positive health outcomes in human clinical studies where fermented foods were used as dietary interventions.Under "The European Cooperation in Science and Technology" (COST) Action CA20128 -"Promoting Innovation of Fermented Foods" PIMENTO framework, a systematic literature search was conducted across PubMed, Scopus, and the Cochrane Library. The search initially identified 2,411 studies, of which 50 met the predefined inclusion criteria. In all included studies, fermented foods were used as nutritional interventions, and the bioactive compounds they contained were either hypothesised or directly analysed in relation to statistically significant health effects observed in humans. Findings were summarised in "Population, Intervention, Comparator, Outcome" (PICO)-structured tables and classified by health domain.The reported effects were grouped under the following categories: cardiovascular health, lipid metabolism, glucose regulation, immune modulation, neuroprotection, liver function, and other health outcomes.Across the included studies, a total of 31 bioactive compounds and/or compound groups were identified in fermented foods, including bioactive peptides, polyphenols (epicatechin, genistein), γ-aminobutyric acid (GABA), acetic acid, curcumin, and arabinoxylans. The mechanisms of action associated with these compounds were explored in the non-systematic section of the review, supported by findings from in vitro, animal and human studies.By linking individual bioactive compounds derived from fermented foods to clinical outcomes and underlying mechanisms, this review provides a comprehensive and functional resource for nutritional science, fermented food innovation, and public health applications.