Therapeutic and Dietary Support for Gastrointestinal Tract Using Kefir as a Nutraceutical Beverage: Dairy-Milk-Based or Plant-Sourced Kefir Probiotic Products for Vegan and Lactose-Intolerant Populations

Kefir is a fermented milk beverage different in consistency and taste from other popular milk-product yogurt. Unlike yogurt prepared using lactic acid bacteria in fermentation, milk is fermented for kefir production using preculture in the form of kefir grains. Therefore, the metabolic activities of a mixed culture, including strains of bacteria and yeast, contribute to the probiotic characteristics in kefir. This article is based on the review of published studies on the functionality and nutraceutical properties of kefir. The therapeutic and dietary properties of kefir beverage and its probiotic strains have been discussed for their several health benefits. Concise selected information mostly from recent reports has been presented for two categories of kefir products: milk used for the production of dairy-based traditional kefir beverages for the lactose-tolerant population, and the plant-sourced substrates used for the production of dairy-free kefir beverages for lactose-intolerant and vegan consumers.