This new monthly feature will provide an overview of some of the latest studies on prebiotics. We’ll share key findings and insights from the studies. Have a study you’d like us to cover? Email GPA Communications Director Traci Kantowski traci@prebioticassociation.org.

These three recently published studies dive into the role of prebiotics and aging.

Flexibility of Gut Microbiota in Ageing Individuals during Dietary Fiber Long-Chain Inulin Intake

Summary: It is understood that dysbiosis can occur as a result of ageing even if there are underlying health conditions associated with the dysbiosis. It is believed that the intestinal microbiota of aged individuals may not respond to interventions that the microbiota of a younger person may respond favorably to. Therefore, a double-blind, placebo-controlled trial was performed in healthy individuals aged 55-80 to assess the changes in microbiota composition before during and after consuming 8g/day of chicory long-chain inulin for two months. Fecal short-chain fatty acid concentrations, T cell subsets, and antibody responses against a Hepatitis B (HB) vaccine are measured as well. Inulin consumption modified the microbiota composition, as measured by 16S rRNA sequencing. Participants consuming inulin have higher microbial diversity and a relatively higher abundance of the Bifidobacterium genus, as well as Alistipes shahii, Anaerostipes hadrus, and Parabacteroides distasonis. The immune responses remain unchanged. The authors concluded that the gut microbiota composition is still sensitive to chicory long-chain inulin induced changes in an ageing population.

Key takeaways: It should be noted that this was a small study, including only 15 people in the treatment group and 13 in the control. Furthermore, these people were relatively young and healthy and results may differ for older individuals with clinical conditions.

Access the study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8138623/

Kiewiet MBG, Elderman ME, El Aidy S, Burgerhof JGM, Visser H, Vaughan EE, Faas MM, de Vos P. Flexibility of Gut Microbiota in Ageing Individuals during Dietary Fiber Long-Chain Inulin Intake. Mol Nutr Food Res. 2021 Feb;65(4):e2000390. doi: 10.1002/mnfr.202000390. Epub 2021 Jan 25.

Adjuvant Effect of Orally Applied Preparations Containing Non-Digestible Polysaccharides on Influenza Vaccination in Healthy Seniors: A Double-Blind, Randomised, Controlled Pilot Trial

Summary: Ageing is associated with decreased immune system function, referred to as immunosenescence. And while vaccinations are considered an effective measure to decrease the risk of many infections and the severity which often improves outcomes, the response to vaccination in the elderly has been found to be considerably weaker than in younger adults, mostly due to the decrease in immune system function. Therefore, it is important to discover methods to enhance immune and vaccine response in elderly individuals. A double-blind, randomized, controlled pilot trial was conducted in 239 subjects aged 50-79 years. Subjects were randomized to receive 5 different non-digestible polysaccharide (NPS) formulations (500mg yeast β-glucan (YBG), 500 mg shiitake β-glucan (SBG), 10g oat β-glucan (OBG), 10g arabinoxylan (AX), bacterial exopolysaccharide (EPS)) or control (CTRL) product daily for five weeks. After two weeks of intervention, subjects were vaccinated with seasonal influenza vaccine. There was a trend increase of HI antibody titres and seroprotection rate against the influenza A H1N1 strain in response to vaccination in subjects consuming AX compared to CTRL. Additionally, subjects consuming AX for five weeks had a higher relative abundance of Bifidobacterium compared to subjects in the CTRL group and a lower incidence of common colds which the authors attribute to the higher Bifidobacterium.

Key Takeaway: This was a small pilot group and therefore findings should be interpreted with caution.

Access the study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8400163/

Laue C, Stevens Y, van Erp M, Papazova E, Soeth E, Pannenbeckers A, Stolte E, Böhm R, Gall SL, Falourd X, Ballance S, Knutsen SH, Pinheiro I, Possemiers S, Ryan PM, Ross RP, Stanton C, Wells JM, Werf SV, Mes JJ, Schrezenmeir J. Adjuvant Effect of Orally Applied Preparations Containing Non-Digestible Polysaccharides on Influenza Vaccination in Healthy Seniors: A Double-Blind, Randomised, Controlled Pilot Trial. Nutrients. 2021 Aug 2;13(8):2683. doi: 10.3390/nu13082683. PMID: 34444843; PMCID: PMC8400163.

Galacto-oligosaccharides supplementation in prefrail older and healthy adults increased faecal bifidobacteria, but did not impact immune function and oxidative stress

Summary: Ageing is associated with an increase in frailty that is associated with a disfavorable change in microbiota composition, immune response and oxidative stress. Prebiotics may help to ameliorate such changes.  A randomized, controlled cross-over study of 20 prefail elderly and 24 healthy adults was conducted to determine if fecal microbiota composition, metabolites in feces and exhaled breath, and parameters of immune function and systemic oxidative stress show perturbations in prefrail elderly when compared with healthy adults, and if these markers can be beneficially altered by four weeks of  15g/day galacto-oligosaccharides (GOS) supplementation. Fecal microbiota composition differed significantly between age groups, with significantly lower relative abundance of Bifidobacterium in the elderly when compared with healthy younger adults. Fecal and breath metabolites, as well as parameters of immune function and systemic oxidative stress did not show significant differences between elderly and adults at baseline. After four weeks of GOS supplementation, microbiota composition of both age groups changed significantly, accompanied by significant increase in Bifidobacterium, significant decrease in microbial diversity (in adults and in elderly) and microbial richness (in elderly). In the elderly and healthy adults, fecal and breath metabolites, and parameters of immune function and systemic oxidative stress were not significantly different when comparing subjects that either received GOS or placebo intervention.

Key takeaways: It should be noted that the elderly subjects were not “frail” or infirmed and that the supplementation only lasted for 4 weeks. Therefore, future studies should investigate different populations of elderly for longer periods of time.

Access the study: https://pubmed.ncbi.nlm.nih.gov/33509667/

Wilms E, An R, Smolinska A, Stevens Y, Weseler AR, Elizalde M, Drittij MJ, Ioannou A, van Schooten FJ, Smidt H, Masclee AAM, Zoetendal EG, Jonkers DMAE. Galacto-oligosaccharides supplementation in prefrail older and healthy adults increased faecal bifidobacteria, but did not impact immune function and oxidative stress. Clin Nutr. 2021 May;40(5):3019-3031. doi: 10.1016/j.clnu.2020.12.034. Epub 2021 Jan 12. PMID: 33509667.

This post was written by Susan Hewlings Ph.D., R.D., Director of Scientific Affairs, Nutrasource/GRAS Associates