Probiotic Supplementation Improves Gut Microbiota and Provides Neuroprotective Effects in Elderly Subjects

by | Jul 17, 2023 | 2023, Aging, Probiotics

Written by Taylor Woosley, Staff Writer. 12-week supplementation of a probiotic containing 1 x 109 CFU Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI in soybean oil/day significantly increased IPA levels (p < 0.05) and in vitro treatment with IPA significantly decreased proinflammatory TNF-α concentration in activated microglia (p < 0.05). 

probioticsAgeing is associated with deterioration of multiple bodily functions and inflammation, leading to the onset of frailty1. In the older population, poor nutrition and decreased gut motility can lead to an imbalanced microbial state2. Gut dysbiosis can negatively affect the microbiome-gut-brain axis which provides a network from the brain to influence functions of the gut while simultaneously allowing signals and metabolites from the gut microbiome to influence brain biochemistry and function3.

The interplay between gut and brain involves a complex network of immunological and neural mediators, which has been considered as a critical target for brain health and neurodegenerative diseases4. Probiotics are live microbes that confer health benefits to the host and research has shown that probiotics may be an effective dietary intervention to ameliorate age-associated cognitive deficits5. Microbial tryptophan metabolites such as indole-3-propionic acid (IPA) may be positively influenced by probiotic consumption and, in addition to short chain fatty acids, exert various effects such as mediating functional T cell responses and promote metabolism of xenobiotics6.

Kim et al. conducted a randomized, double-blind, placebo-controlled multicenter trial to analyze the mechanisms underlying the neuroprotective effects of probiotic supplementation. 53 healthy subjects over the age of 65 years were included in the study and assigned to either the probiotic group (n=27) or the placebo group (n=26) for a 12-week intervention. The probiotic group consumed a capsule of 1 x 109 CFU Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI in soybean oil/day while the placebo group consumed a capsule of 2 g of soybean oil per day. Blood samples and stool samples were obtained at baseline and at the end of the intervention (12th week) for gut microbiota analysis.

A Kolmogorov-Smirnov test was utilized to test for the study variables’ normality assumption and homogeneity of variance. Mann-Whitney U test or an unpaired t-test was performed for between-group analysis and a Wilcoxon signed-rank test, or a paired t-test was used for within-group analysis. 24 subjects in the placebo group and 26 participants in the probiotic group had serum samples used for metabolomic profiling, which included 12 differential metabolites. Significant findings of the study are as follows:

  • 12-week supplementation of probiotics showed an increase in IPA, a metabolite involved in tryptophan metabolism, in the probiotic group alone (fold change = 1.91, p < 0.05).
  • Bile acid metabolites increased in the probiotics group, specifically chenodeoxycholic acid (CDCA) (fold change = 2.18, p < 0.05), along with secondary bile acids.
  • In vitro treatment with IPA significantly decreased proinflammatory TNF-α concentration in activated microglia (p < 0.05).

Results of the study show that probiotic supplementation positively influences changes in gut microbiota. The significant increase in IPA was also associated with serum brain-derived neurotropic factor levels. Further research should include animal and clinical studies to better comprehend IPA’s potential neuroprotective effects.

Source: Kim, Chong-Su, Sunhee Jung, Geum-Sook Hwang, and Dong-Mi Shin. “Gut microbiota indole-3-propionic acid mediates neuroprotective effect of probiotic consumption in healthy elderly: A randomized, double-blind, placebo-controlled, multicenter trial and in vitro study.” Clinical Nutrition 42, no. 6 (2023): 1025-1033.

© 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Click here to read the full text study.

Posted July 17, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

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