A comparative case study of artisanal grain-based and commercial milk kefir: an in vitro investigation on anti-inflammatory activity

Kefir is produced through the symbiotic activity of lactic and acetic acid bacteria along with yeasts, microbiota's structure differs between artisanal grain-based kefir beverage (KB) and commercial kefir (KC) and its contribution in ameliorating inflammation is still not elucidated. This case study combines culture-dependent and culture-independent (qPCR-based) quantification to characterize kefir microbiota, including kefir-associated grains (KG), to assess their potential anti-inflammatory properties. qPCR-based quantification revealed a higher concentration of different LAB and yeasts species in KB and KG compared to KC, along with Acetobacter spp., underscoring the microbial variety. Anti-inflammatory analysis using inflamed intestinal epithelial cells showed a greater ability of KB to reduce pro-inflammatory IL-6 and IL-17A cytokines expression, potentially driven by KG. Results suggests the potential role of microbial composition of kefir grains on kefir's anti-inflammatory effects, warranting further research to ultimately guide the development of targeted functional foods for improving gut health.