Eastern European Fermented Foods: Nutritional Value, Functional Potential, and Cultural Heritage

Background: Fermentation is among the oldest and most versatile food processing techniques, enhancing not only shelf life but also nutritional and functional value. While Asian and Western fermented foods are extensively studied, traditional Eastern European fermentations—such as sauerkraut, kefir, bryndza, kvass, and sourdough—remain largely unexplored despite their enduring cultural and dietary importance. These foods combine spontaneous or mixed-culture fermentations, diverse substrates, and unique microbial consortia that may yield distinct bioactive profiles with potential health benefits. Methods: This narrative review synthesizes data from scientific articles, regional reports, and ethnographic sources retrieved from PubMed, Scopus, and Google Scholar up to 2025. Studies were selected for relevance to composition, microbiology, bioactive compounds, and human or experimental health outcomes related to Eastern European fermented foods. Results: Available evidence indicates that traditional fermented dairy, cereal, and vegetable products from Eastern Europe contain fermentation-derived bioactive compounds, including specific bioactive peptides, transformed polyphenols, microbial-synthesized vitamins, organic acids, and live or non-viable microorganisms. Experimental studies describe the generation of ACE-inhibitory peptides, polyphenol biotransformation, and prebiotic or postbiotic metabolites with reported antioxidant, antihypertensive, immunomodulatory, and metabolic effects. However, substantial variability in artisanal production practices and the limited number of standardized human studies currently constrain definitive conclusions. Conclusions: Eastern European fermented foods represent a culturally unique yet scientifically undercharacterized component of functional nutrition. Their complex microbial ecosystems and diverse substrates offer valuable models for studying diet–microbe interactions. Further omics-based and clinical research is warranted to clarify bioavailability, mechanisms of action, and their potential integration into evidence-based dietary strategies.