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.
Aging processes affect the brain in many ways, ranging from cellular to functional levels which lead to cognitive decline and increased oxidative stress. The aim of this study was to investigate the potentials of Lactobacillus plantarum DR7 on brain health including cognitive and memory functions during aging and the impacts of high fat diet during a 12-week period. Male Sprague-Dawley rats were separated into six groups: (1) young animals on normal diet (ND, (2) young animals on a high fat diet (HFD), (3) aged animals on ND, (4) aged animals on HFD, (5) aged animals on HFD and L. plantarum DR7 (109 cfu/day) and (6) aged animals receiving HFD and lovastatin. To induce ageing, all rats in group 3 to 6 were injected sub-cutaneously at 600 mg/kg/day of D-galactose daily. The administration of DR7 has reduced anxiety accompanied by enhanced memory during behavioural assessments in aged-HFD rats (P<0.05). Hippocampal concentration of all three pro-inflammatory cytokines were increased during aging but reduced upon administration of both statin and DR7. Expressions of hippocampal neurotransmitters and apoptosis genes showed reduced expressions of indoleamine dioxygenase and P53 accompanied by increased expression of TPH1 in aged- HFD rats administered with DR7, indicating potential effects of DR7 along the pathways of serotonin and oxidative senescence. This study provided an insight into potentials of L. plantarum DR7 as a prospective dietary strategy to improve cognitive functions during aging. This study provided an insight into potentials of L. plantarum DR7 as a prospective dietary strategy to improve cognitive functions during aging.