Kefir as a therapeutic agent in clinical research: a scoping review

Abstract

Increasing research has been conducted on the role of probiotics in disease treatment. Kefir, a safe, low-cost probiotic fermented milk drink, has been investigated in many in vitro and animal studies, although parameters for human therapeutic dose or treatment time have not yet been determined. To perform a scoping review of clinical studies that have used kefir as a therapeutic agent, compiling the results for perspectives to support and direct further research. This review was based on Joanna Briggs Institute guidelines, including studies on the effects of kefir-fermented milk in humans. Using the term KEFIR, the main international databases were searched for studies published in English, Spanish, or Portuguese until March 9, 2022. A total of 5835 articles were identified in the 4 databases, with 44 eligible for analysis. The research areas were classified as metabolic syndrome and type 2 diabetes, gastrointestinal health/disorders, maternal/child health and pediatrics, dentistry, oncology, women’s and geriatric health, and dermatology. The many study limitations hampered generalization of the results. The small sample sizes, methodological variation, and differences in kefir types, dosage, and treatment duration prevented clear conclusions about its benefits for specific diseases. We suggest using a standard therapeutic dose of traditionally prepared kefir in milliliters according to body weight, making routine consumption more feasible. The studies showed that kefir is safe for people without serious illnesses.

Nutritional Characteristics, Health Impact, and Applications of Kefir

“…Kefir is a fermented milk beverage produced by the synergistic action of bacteria and yeasts contained in kefir grains that have an inert matrix of polysaccharides and proteins and are home to a diverse range of microorganisms, including lactic acid bacteria (LAB), acetic acid bacteria, and yeasts [9,10]. The intricate interactions of these multiple microbes, as well as several bioactive substances produced by their metabolic processes, contribute to kefir's reputation as a natural probiotic [9,[11][12][13][14].…”

“…Kefir is a fermented milk beverage produced by the synergistic action of bacteria and yeasts contained in kefir grains that have an inert matrix of polysaccharides and proteins and are home to a diverse range of microorganisms, including lactic acid bacteria (LAB), acetic acid bacteria, and yeasts [9,10]. The intricate interactions of these multiple microbes, as well as several bioactive substances produced by their metabolic processes, contribute to kefir's reputation as a natural probiotic [9,[11][12][13][14]. The microbial composition of kefir can vary based on factors like geographical origin, fermentation duration, substrate, and processing methods, yet kefir grains consistently maintain a relatively stable and distinctive microbiota, often characterized by the prevalence of specific Lactobacillus species [15].…”