Probiotics as an adjunct for the treatment of recurrent wheezing in infants and effects on expression of T-helper 1 and regulatory T cytokines

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

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. Here we 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 9 March 2022. A total of 5835 articles were identified in the four databases, with forty-four eligible for analysis. The research areas were classified as metabolic syndrome and type 2 diabetes, gastrointestinal health/disorders, maternal/child health and paediatrics, dentistry, oncology, women's and geriatric health, and dermatology. The many study limitations hampered generalisation 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 millilitres according to body weight, making routine consumption more feasible. The studies showed that kefir is safe for people without serious illnesses.

The effects of kefir consumption on human health: a systematic review of randomized controlled trials

CONTEXT

Kefir, a traditional, fermented-milk beverage, has increasingly been promoted for various health benefits. The evidence from systematic reviews, however, is limited.

OBJECTIVE

Evidence from randomized controlled trials testing oral consumption of fermented-milk kefir on any outcome of human health or disease.

DATA SOURCES

A systematic search of 4 electronic databases (PubMed, Scopus, Allied and Complementary Medicine Database, and Cochrane Trials) from inception to July 31, 2021, was conducted.

DATA EXTRACTION

Data extraction and risk-of-bias assessments were conducted by 2 reviewers independently.

DATA ANALYSIS

A total of 18 publications reporting the results of 16 studies were included. Per the narrative analysis, fermented-milk kefir may have potential as a complementary therapy in reducing oral Streptococcus mutans, thereby reducing dental caries risk, and in Helicobacter pylori eradication therapy. Kefir may further aid treatment of adult dyslipidemia and hypertension, although evidence was very limited. Safety was only assessed in 5 of the 18 included publications, and 12 of the studies had an overall high risk for bias.

CONCLUSION

Kefir is a dairy product with a unique microbiological profile that appears to be a safe for generally healthy populations to consume. However, efficacy and safety data from high-quality human trials are essential before any recommendations may be made for conditions of the oral and gastric microbiota and metabolic health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020211494.