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Efficacy and Safety of Lactobacillus Plantarum C29-Fermented Soybean (DW2009) in Individuals with Mild Cognitive Impairment: A 12-Week, Multi-Center, Randomized, Double-Blind, Placebo-Controlled Clinical Trial.
Hwang, YH, Park, S, Paik, JW, Chae, SW, Kim, DH, Jeong, DG, Ha, E, Kim, M, Hong, G, Park, SH, et al
Nutrients. 2019;11(2)
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Mild cognitive impairment (MCI) describes a range of symptoms that impact on cognition and memory, but not to such an extent that it seriously affects a person's day to day life. People with MCI are at higher risk of going on to develop dementia. Consumption of both probiotics and soy beans have been shown to enhance memory function in previous studies on animals and humans. In this Korean study, a randomised, double-blind, placebo-controlled trial, researchers used soybeans that had been fermented with a bacterium called Lactobacillus plantarum C29, a type of bacteria which is found in the traditional Korean food kimchi. One hundred men and women diagnosed with MCI were given capsules containing either 800 mg of dried fermented soybeans or a placebo for 12 weeks. Participants underwent a series of memory and attention tests to measure cognitive function. Researchers also looked at levels of a protein that supports nerve cells, called brain-derived neurotropic factor (BDNF) in the blood, as well as the composition of bacteria in the stool samples of the participants. The group that consumed the fermented soybeans showed greater improvements in the overall cognitive function, especially attention, compared to those who took the placebo. BDNF levels increased in the soybean group but declined in the placebo group. Increases in BDNF were associated with improvements in cognitive function. The results of this clinical trial suggest that fermented soybeans can be safely consumed by people with MCI to enhance cognitive function. The authors suggested that the increase in blood BDNF levels may be partly responsible for the improved cognitive function, and this in turn points to the importance of the so-called gut-brain axis in improving symptoms of MCI.
Abstract
Early intervention using dietary supplements may be effective in alleviating cognitive impairment among individuals with mild cognitive impairment (MCI). This study investigated the efficacy and safety of Lactobacillus plantarum C29-fermented soybean (DW2009) as a nutritional supplement for cognitive enhancement. One hundred individuals with MCI were randomly assigned to take DW2009 (800 mg/day, n = 50) or placebo (800 mg/day, n = 50) for 12 weeks. The primary outcome measure was change in the composite score of cognitive functions related to memory and attention, measured by computerized neurocognitive function tests. Associations between changes in serum brain-derived neurotrophic factor (BDNF) levels and cognitive performance for each treatment group were evaluated. Compared to the placebo group, the DW2009 group showed greater improvements in the combined cognitive functions (z = 2.36, p for interaction = 0.02), especially in the attention domain (z = 2.34, p for interaction = 0.02). Cognitive improvement was associated with increased serum BDNF levels after consumption of DW2009 (t = 2.83, p = 0.007). The results of this clinical trial suggest that DW2009 can be safely administered to enhance cognitive function in individuals with MCI. Increased serum BDNF levels after administering DW2009 may provide preliminary insight into the underlying effects of cognitive improvement, which suggests the importance of the gut-brain axis in ameliorating cognitive deficits in MCI.
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Stress matters: Randomized controlled trial on the effect of probiotics on neurocognition.
Papalini, S, Michels, F, Kohn, N, Wegman, J, van Hemert, S, Roelofs, K, Arias-Vasquez, A, Aarts, E
Neurobiology of stress. 2019;10:100141
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Increasing animal studies indicate the role of probiotics in regulating mood and cognition through the gut-brain axis, however in human studies evidence of this causal association is lacking. The aim of this double-blind, randomised, placebo-controlled intervention was to investigate the effects of probiotics on neurocognitive measures in 58 healthy participants. Participants were randomly assigned to either probiotic or placebo group and were tested once before and after the 28-day intervention. The neurocognitive outcomes measured included emotion reactivity, emotion regulation, cognitive control and the effects of acute stress on working memory. These were assessed through functional MRI (fMRI) and questionnaires. This study found when stress was induced, probiotic supplementation led to a significant improvement in working memory performance. Without stress, there was no causal association between neurocognitive outcomes and probiotic intake. Based on these results, the authors conclude that during challenging situations, probiotics can aid in buffering the detrimental effects of stress on cognition.
Abstract
Probiotics are microorganisms that provide health benefits when consumed. In animals, probiotics reverse gut microbiome-related alterations in depression-like symptoms, in cognition, and in hormonal stress response. However, in humans, a causal understanding of the gut-brain link in emotion and cognition is lacking. Additionally, whether the effects of probiotics on neurocognition are visible only in presence of stress, remains unclear. We investigated the effects of a multispecies probiotic (EcologicĀ®Barrier) on specific neurocognitive measures of emotion reactivity, emotion regulation, and cognitive control using fMRI. Critically, we also tested whether probiotics can buffer against the detrimental effects of acute stress on working memory. In a double blind, randomized, placebo-controlled, between-subjects intervention study, 58 healthy participants were tested once before and once after a 28-day intervention. Without stress induction, probiotics did not affect brain, behavioral, or related self-report measures. However, relative to placebo, the probiotics group did show a significant stress-related increase in working memory performance after supplementation. This change was associated with intervention-related neural changes in frontal cortex during cognitive control exclusively in the probiotics group. Overall, our results show neurocognitive effects of a multispecies probiotic in healthy women only under challenging situations, buffering against the detrimental effects of stress on cognition.