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Home > Trending on TAP > February 2019 > Probiotics Buffer the Effects of Stress on Memory

Probiotics Buffer the Effects of Stress on Memory

2/5/2019 3:30:26 PM

Probiotics may mediate mood and cognition via the gut-brain axis. Human studies have found that probiotics decrease symptoms of depression associated with intestinal disease. Researchers in the Netherlands conducted a randomized controlled trial to assess the effects of a multispecies probiotic on neurocognitive and emotional function.  
 
The probiotic was Ecologic®Barrier (2 grams once a day), given in powder form to be mixed in water or milk and taken on an empty stomach. It contained Bifidobacterium bifidum W23, Bifidobacterium lactis W51, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24, Lactococcus lactis W19, and Lactobacillus lactis W58. This probiotic had previously been shown to strengthen epithelial barrier function and decrease intestinal permeability for the endotoxin lipopolysaccharide (LPS).
 
Fifty-eight healthy women (aged 18-40) were randomized to take a placebo or the probiotic for 28 days. At baseline and the end of the trial, the women engaged in neurocognitive tests along with functional magnetic resonance imaging (fMRI). The tests evaluated emotion reactivity, emotion regulation, cognitive control, and working memory before and after acute stress.
 
Results showed no difference between the probiotic and placebo on self-reported, behavioral, or fMRI measurements of emotion reactivity, emotion regulation, or cognitive control. There was, however, a positive finding for the ability of probiotics to buffer the adverse effects of stress on working memory. In the probiotic group, the better working memory performance after stress was also associated with neural changes in the frontal cortex.
 
It should be noted that the beneficial effect of probiotics on stress-related cognition was not accompanied by changes in cortisol or sympathetic nervous system markers. The mechanism is not known but may involve modulation of intestinal permeability, LPS, or inflammatory cytokines. The authors also suggest that probiotics might release metabolites that are precursors of monoamine neurotransmitters. Future studies will need to confirm these proposed mechanisms of action.
 
This study builds on the growing body of research suggesting a link between the gut microbiome and brain health. The main finding was that a multispecies probiotic, taken for 28 days, buffers the adverse effects of stress on working memory performance in healthy women.
 
Reference
Papalini S, Michels F, Kohn N et al. Stress matters: a double-blind, randomized controlled trial on the effects of a multispecies probiotic on neurocognition. BioRxiv. 2018.  

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