Putative Probiotic Strains Isolated from Kefir Improve Gastrointestinal Health Parameters in Adults: a Randomized, Single-Blind, Placebo-Controlled Study

The dairy products remain as the largest reservoir for isolation of probiotic microorganisms. While probiotics have been immensely reported to exert various health benefits, it is also a common notion that these health potentials are strain and host dependent, leading to the need of more human evidence based on specific strains, health targets, and populations. This randomized, single-blind, and placebo-controlled human study aimed to evaluate the potential benefits of putative probiotic strains isolated from kefir on gastrointestinal parameters in fifty-six healthy adults. The consumption of AB-kefir ( Bifidobacterium longum , Lactobacillus acidophilus , L. fermentum , L. helveticus , L. paracasei , L. rhamnosus , and Streptococcus thermophiles ; total 10 log CFU/sachet) daily for 3 week reduced symptoms of abdominal pain, bloating ( P = 0.014), and appetite ( P = 0.041) in male subjects as compared to the control. Gut microbiota distribution profiles were shifted upon consumption of AB-kefir compared to baseline, where the abundance of bifidobacteria was increased in male subjects and maintained upon cessation of AB-kefir consumption. The consumption of AB-kefir also increased gastrointestinal abundance of total anaerobes ( P = 0.038) and total bacterial ( P = 0.049) in female subjects compared to the control after 3 weeks. Our results indicated that AB-kefir could potentially be developed as a natural strategy to improve gastrointestinal functions in adults.