Can probiotics improve memory?

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  • Can probiotics improve memory

Increasing evidence supports the effect of probiotics on cognition, anxiety, depression and other mood behaviours; however, no research to date has looked at their potential effects on memory function. In a recent experimental study, researchers found the clinically researched probiotic blend, Lab4, had beneficial effects on age-related memory function and brain metabolites.

Based on the evidence that bifidobacteria and lactobacilli have positive effects on brain network activity, gene expression and synaptic plasticity, the researchers examined the effect of the probiotic mix, known as Lab4, consisting of Lactobacillus acidophilus CUL60 and CUL21, Bifidobacterium bifidum CUL20 and Bifidobacterium lactis CUL34.

Using ageing rat models, tests were performed to analyse the effects of long term Lab4 intake on memory and behavioural flexibility. The results revealed improvements in long-term object recognition memory (remembering the prior occurrence of an object) and short-term memory for object-in-place associations (remembering the association between an object and place in which it was previously encountered).

Analysis of the brain metabolites and activity showed increases in GABA signalling in the frontal cortex, suggesting the probiotics influenced the GABA/glutamate-glutamine cycle, which is consistent with previous findings. An increase in myo-inositol was also found, a metabolite often low in depressed patients. Taken together, the authors stated that these increases may reflect increased modulation of glutamate transmission, and potentially synaptic plasticity, in the brain.

Increased levels of lactate were also found in the hippocampus and frontal cortex. Lactate, a by-product of probiotic metabolism, provides energy to the brain and has been linked with the establishment of long-term memories. Additionally, inosine, a metabolite found to enhance recognition memory, was increased in the hippocampal regions.[1]

This preclinical study adds to the evidence of how manipulation of the gut microbiome can impact brain activity and memory. It also adds to the current research behind the Lab4 probiotic mix.

The probiotics in Lab4 have also been shown to have a beneficial immunomodulatory effect on healthy individuals by altering cytokine production,[2] and to significantly reduce IBS symptoms,[3] upper respiratory tract infection symptom duration and incidence rates,[4] antibiotic associated dysbiosis,5 clostridium-associated diarrhoea6 and allergic eczema occurrence.[7]


  1. O’Hagan C, Li JV, Marchesi JR, et al. Long-term multi-species Lactobacillus and Bifidobacterium dietary supplement enhances memory and changes regional brain metabolites in middle-aged rats. Neurobiol Learn Mem 2017;144:36-47. [Abstract
  2. Hepburn NJ, Garaiova I, Williams EA, et al. Probiotic supplement consumption alters cytokine production from peripheral blood mononuclear cells: a preliminary study using healthy individuals. Benef Microbes 2013;4(4):313-317. [Abstract
  3. Williams EA, Stimpson J, Wang D, et al. Clinical trial: a multistrain probiotic preparation significantly reduces symptoms of irritable bowel syndrome in a double-blind placebo-controlled study. Aliment Pharmacol Ther 2009;29(1):97-103. [Full Text
  4. Garaiova I, Muchova J, Nagyova Z, et al. Probiotics and vitamin C for the prevention of respiratory tract infections in children attending preschool: a randomised controlled pilot study. Eur J Clin Nutr 2015;69(3):373-379. [Full Text]
  5. Plummer SF, Garaiova I, Sarvotham T, et al. Effects of probiotics on the composition of the intestinal microbiota following antibiotic therapy. Int J Antimicrob Agents 2005;26(1):69-74. [Abstract
  6. Plummer S, Weaver MA, Harris JC, et al. Clostridium difficile pilot study: effects of probiotic supplementation on the incidence of C. difficile diarrhoea. Int Microbiol 2004;7(1):59-62. [Full Text
  7. Allen SJ, Jordan S, Storey M, et al. Probiotics in the prevention of eczema: a randomised controlled trial. Arch Dis Child 2014;99(11):1014-1019. [Full Text


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Melissa Peterson has been a writer and educator in the health and medical science fields for over 15 years. Naturopathically trained, Melissa also has postgraduate qualifications in literature research and reviewing. Her business, Words On Therapy, provides many services to industry including technical articles, white papers, blogs, SEO content, copywriting and research collation.