What’s the Latest in Prebiotic Research?

August 2024 Edition

Beneficial effects of synbiotics on the gut microbiome in individuals with low fiber intake: secondary analysis of a double-blind, randomized controlled trial

Fiber is an essential dietary component, conferring positive and preventative effects on the risk of developing heart diseases, metabolic diseases, and even malignant tumors. Consistent, long-term fiber consumption has been shown to influence the gut microbiota by modifying bacterial fermentation, colony size, and species composition. Alternatively, low fiber intake has been linked with unfavorable health consequences, specifically lowering gut microbial diversity and richness . This randomized controlled trial investigated the effects of synbiotic intake on the diversity of the gut microbiome in individuals with low dietary fiber intake (<25 g/day). One-hundred and seventeen healthy male participants (22-42 years) received either a 2 g synbiotic supplement containing inulin derived from agave along with 2×109 colony forming units (CFU) of Bifidobacterium lactis, Lactobacillus acidophilus, L. casei, L. salivarius, and Lactococcus lactis or placebo (microcrystalline cellulose). The test products were administered once daily for seven weeks while maintaining dietary habits and physical activity. Both intervention groups were further divided for analysis into a low fiber group (LFG; <25 g/day) and a high fiber group (HFG; ≥25 g/day), and stool samples were collected before and after intervention for microbiome analysis. At seven weeks of the synbiotic intervention, a significant increase was reported in the abundance of short-chain fatty acid (SCFA)-producing microbes in the LFG and this effect was less evident in the HFG. The seven-week duration of this study is considered a mid-term intervention period, and future longer-in-duration studies are needed to validate these results.

Key takeaways:

  • Fiber is an essential nutritional component in health maintenance and disease prevention.
  • Synbiotics formulated with dietary fiber benefit the gut microbiome of individuals with generally low fiber intake. 
  • This study showed that the intake of synbiotics may improve the gut microbiome of participants with low fiber intake, with individual variability observed according to the baseline dietary fiber intake.

Access to the study: https://pubmed.ncbi.nlm.nih.gov/38999830/ 

Reference: Mantri, A., Klümpen, L., Seel, W., Krawitz, P., Stehle, P., Weber, B., Koban, L., Plassmann, H., & Simon, M. C. (2024). Beneficial Effects of Synbiotics on the Gut Microbiome in Individuals with Low Fiber Intake: Secondary Analysis of a Double-Blind, Randomized Controlled Trial. Nutrients, 16(13), 2082. https://doi.org/10.3390/nu16132082

Effects of almond consumption compared with the consumption of traditional isocaloric cereal/pulse-based snacks on glycaemic control and gut health in adults with pre-diabetes in rural India: protocol for a 16-week, parallel-arm, cluster randomised controlled trial

Nutrition interventions can avert cardiovascular and metabolic diseases by modulating risk factors such as hyperglycemia. India is at the forefront of the nations burdened by escalating numbers of diabetes and coronary artery disease, predisposed by a genetic phenotype characterized by elevated levels of central adiposity, diabetes, insulin resistance, and dyslipidemia, exacerbated by lifestyle factors such as unhealthy diet and lack of physical activity. Almonds contain healthy unsaturated fats, fiber, proteins, vitamins E and B complex, calcium, magnesium, copper, phytosterols, and prebiotic components such as pectic substances, hemicellulose, and polyphenols. Western studies have shown almonds’ numerous beneficial effects on lipid profile, atherogenic indices, endothelial function, inflammatory markers, glycemic control, Hemoglobin A1c (HbA1c), and blood pressure. This 16-week randomized, parallel-arm, controlled dietary intervention aims to evaluate the effects of 56g daily almond supplementation on rural Indian individuals with pre-diabetes. One-hundred and seventy-eight participants with prediabetes (20-50 years; body mass index: 18.9-25 kg/m2) will receive 56 g of almonds as a mid-morning snack, while the control group will receive cereal/pulse-based traditional isocaloric snacks. The primary endpoint is HbA1c at 16 weeks, while the secondary outcomes included anthropometry, clinical and biochemical parameters, and gut health analysis of a subgroup of 120 participants.
 
Key takeaways:
  • Nutrition interventions can prevent cardiovascular and metabolic diseases by modulating risk factors like hyperglycemia.
  • India faces high rates of diabetes and coronary artery disease, exacerbated by genetic predispositions and lifestyle choices.
  • Almonds, rich in beneficial nutrients, have shown positive effects on lipid profiles, glycemic control, and other health markers in Western studies.
  • This 16-week randomized study will evaluate the effects of 56 g daily almond supplementation on prediabetic individuals in rural India, focusing on HbA1c, anthropometry, clinical and biochemical parameters, and gut health.

Access the study: https://pubmed.ncbi.nlm.nih.gov/38960469/

Reference: Ruchi, V., Nayanjeet, C., Kalra, P., Nair, N. S., & Prabhakar, B. (2024). Effects of almond consumption compared with the consumption of traditional isocaloric cereal/pulse-based snacks on glycaemic control and gut health in adults with pre-diabetes in rural India: protocol for a 16-week, parallel-arm, cluster randomised controlled trial. BMJ open, 14(7), e076934. https://doi.org/10.1136/bmjopen-2023-076934

Efficacy of a synbiotic in the management of adults with attention-deficit and hyperactivity disorder and/or borderline personality disorder and high levels of irritability: Results from a multicenter, randomized, placebo-controlled, "basket" trial

Attention-deficit and hyperactivity disorder (ADHD) and borderline personality disorder (BPD) are two different yet highly comorbid psychiatric conditions with high symptom overlap. Irritability, which is an increased proneness to anger, commonly worsens prognosis and increases mortality in individuals with ADHD and/or BPD. Recently, researchers have hypothesized that ADHD and BPD share a biological background. Additionally, gut microbial dysbiosis has been implicated in the pathophysiology of both conditions. As such, this randomized, double-blind, placebo-controlled study explored the superiority of a synbiotic (containing 2.5 g each of β-glucan, inulin, pectin, and resistant starch as well as 4×1011 CFU of Pediococcus pentosaceus 5–33:3/16:1, Lactobacillus casei ssp paracasei F19, L. plantarum 2362, and Leuconostoc mesenteroides 77:1) over placebo (maltodextrin) for ten weeks. One-hundred and eighty adults (18-65 years) diagnosed with ADHD and/or BPD that experience high levels of irritability (Affectivity Reactivity Index (ARI-S) ≥ 5 and a Clinical Global Impression-Severity Scale (CGI-S) score ≥ 4) were included in the study. The primary outcome was the end-of-treatment response (a reduction ≥ 30 % in the ARI-S total score compared to baseline, plus a Clinical Global Impression-Improvement (CGI-I) total score of < 3 at week ten), and the secondary outcomes included emotional dysregulation, impulsivity, inattention, functioning and/or perceived stress levels, and safety. Of the 180 randomized participants, 117 were female, 113 had ADHD, 44 had BPD, and 23 had both conditions. At ten weeks, the synbiotic group experienced a significantly higher response rate compared to the placebo group. Additionally, the synbiotic group reported significant changes in all secondary outcomes (p = 0.03) and no safety concerns. Nonetheless, prospective studies with larger sample sizes are needed to confirm these findings.
 
Key takeaways:
  • ADHD and BPD are comorbid psychiatric conditions commonly exacerbated by irritability.
  • This study tested a synbiotic versus placebo for managing high irritability in adults with ADHD and BPD.
  • The synbiotic group showed significantly better outcomes in irritability and secondary measures, such as emotional dysregulation, impulsivity, and inattention, with no safety concerns.
  • Future studies with larger sample sizes are warranted to confirm these results.

Access the study: https://pubmed.ncbi.nlm.nih.gov/38885746/

Reference: Arteaga-Henríquez, G., Ramos-Sayalero, C., Ibañez-Jimenez, P., Karina Rosales-Ortiz, S., Kilencz, T., Schiweck, C., Schnorr, I., Siegl, A., Arias-Vasquez, A., Bitter, I., Fadeuilhe, C., Ferrer, M., Lavebratt, C., Matura, S., Reif, A., Réthelyi, J. M., Richarte, V., Rommelse, N., & Antoni Ramos-Quiroga, J. (2024). Efficacy of a synbiotic in the management of adults with Attention-Deficit and Hyperactivity Disorder and/or Borderline Personality Disorder and high levels of irritability: Results from a multicenter, randomized, placebo-controlled, “basket” trial. Brain, behavior, and immunity, 120, 360–371. https://doi.org/10.1016/j.bbi.2024.06.012

Impact of combined prebiotic galacto-oligosaccharides and Bifidobacterium breve-derived postbiotic on gut microbiota and HbA1c in prediabetic adults: A double-blind, randomized, placebo-controlled study

Prediabetes is a metabolic condition characterized by elevated blood glucose levels, considered an intermediate stage between normal glucose levels and type 2 diabetes mellitus (T2DM), and commonly progresses to T2DM if left unmanaged. Diagnosing prediabetes is challenging due to its asymptomatic nature, leading to underdiagnosis and delayed intervention. There is increasing evidence suggesting that imbalances in gut microbiota may contribute to metabolic disorders, causing various complications for glucose metabolism, energy expenditure, and intestinal permeability. Prebiotics combined with postbiotics may be used to manage these complications, as prebiotics positively regulate microbiota composition while postbiotics enhance gut barrier function. This randomized, double-blinded, placebo-controlled study investigated the effects of 5 g/day dietary fiber (DF) supplementation (containing 32% konjac glucomannan (KGM), 60% galactooligosaccharides (GOSs), and 8% exopolysaccharides (EPSs) from B. breve) or placebo (cellulose microcrystalline) in 53 prediabetic volunteers randomly assigned a treatment for a duration of 12 weeks. Assessments included gut health (gut microbial composition and intestinal permeability), metabolic function (glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG)), alterations in anthropometry, body composition, blood pressure, plasma lipids, and total protein and diet. The study showed a significant increase in the alpha diversity of the gut microbiota and butyrate-producing bacteria, with reductions reported in HbA1c and FPG below the prediabetes threshold. However, there were no significant decrease in the other parameters. These findings suggest that modifying the gut microbiota through dietary interventions may be a promising approach to managing prediabetes or preventing and delaying the development of diabetes.
 
Key takeaways:
  • Prediabetes is an intermediate stage between normal glucose levels and T2DM, often progressing to T2DM if left unmanaged.
  • This study examined the effects of a combination supplement containing prebiotics and a postbiotic on gut health, metabolic function, and diet in prediabetic individuals for 12 weeks.
  • Significant improvement was reported in gut microbiota alpha diversity, butyrate-producing bacteria, and reductions in HbA1c and fasting plasma glucose levels.
  • Dietary interventions targeting the gut microbiota may help manage prediabetes and delay the onset of diabetes.

Access the study: https://pubmed.ncbi.nlm.nih.gov/39064648/

Reference: Beteri, B., Barone, M., Turroni, S., Brigidi, P., Tzortzis, G., Vulevic, J., Sekulic, K., Motei, D. E., & Costabile, A. (2024). Impact of Combined Prebiotic Galacto-Oligosaccharides and Bifidobacterium breve-Derived Postbiotic on Gut Microbiota and HbA1c in Prediabetic Adults: A Double-Blind, Randomized, Placebo-Controlled Study. Nutrients, 16(14), 2205. https://doi.org/10.3390/nu16142205