Kefir: a fermented plethora of symbiotic microbiome and health

Abstract In recent decades, a global shift in lifestyle and the ubiquitous consumption of junk foods have led to dysbiosis and other metabolic disorders significantly impacting human health. Recent studies performed on traditional foods have shown several health benefits and have gained the attention of the scientific community towards ethnic foods. In this regard, the consumption of ethnic foods with symbiotic properties is increasing gradually across the globe. Kefir is one such ethnic food with excellent functional properties. It is a unique traditional fermented drink comprised of kefir grains and probiotic microbes. Kefir grains are a gelatinous consortium of casein, milk solids coupled with yeasts, and lactobacilli-rich microbiota embedded in a poly-saccharide matrix. These components act as starters, initiating fermentation when introduced into fresh milk. This beverage bestows a myriad of symbiotic benefits, encompassing improved gut health and preventing several metabolic and other diseases through various biological mechanisms. Despite its millennia-long history, it has recently gained prominence due to emerging biotechnological and nutraceutical applications and researchers’ burgeoning fascination. In this comprehensive review, we endeavour to provide a meticulous elucidation of the most recent advancements concerning kefir, encompassing its production and processing methodologies for both dairy and water kefir. Furthermore, we delve into the intricate mechanisms underlying its functional properties and the health benefits of kefir as a functional fermented beverage.