Abstract

Cancer is a multifactorial disease with a high incidence and prevalence worldwide. The World Health Organization (WHO) estimates that one-third of cancer deaths are due to modifiable factors, including an unhealthy lifestyle. This has led the scientific community to show increasing interest in studies focused on discovering the potential benefits of certain foods, such as kefir, a fermented dairy product that is easily accessible and widely consumed by the population. The quality guarantees offered by the dairy industry make its consumption safe, which, combined with its low cost, makes it a promising food in the field of research. Therefore, the objective of this narrative literature review was to evaluate the existing scientific evidence on the possible beneficial effects of kefir in the prevention or treatment of cancer. To this end, a bibliographic search of the existing scientific literature was conducted using keywords from January 2014 to the present using the PubMed, Cochrane, Science Direct, and Scopus databases. Other sources of information, including archives of public institutions, were also consulted. A total of 16 scientific papers were selected, which investigated the possible anticancer effects exerted by kefir or a bacterial strain isolated from its culture. The collected studies obtained their findings through cell lines or animal models and investigated various types of cancer, but especially colorectal cancer. The results of this review suggest that kefir, through the action exerted by certain of its bioactive compounds (peptides, polysaccharides, and other lipid-based compounds) or a specific bacterial strain, could be beneficial in the prevention or treatment of cancer. However, to date, there are no published clinical trials confirming this anticancer efficacy in humans. Furthermore, the studies analyzed indicate that more in vitro studies are needed to more accurately elucidate the complex mechanisms involved in its potential anticancer effects, as well as well-designed clinical trials in humans using kefir with a standardized and well-defined composition in order to obtain conclusive and reproducible results.

Keywords

kefir, cancer, mechanisms, benefits, health, prevention