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Evidence-Based Supplement Research
Evidence-Based Supplement Research

Study Design

Type
Randomized Controlled Trial (RCT)
Sample size
n = 60
Population
60 participants (aged 50-90 years) with mild to moderate Alzheimer's disease
Methods
In a 12-week, randomized, double-blind, placebo-controlled trial, participants were assigned to three groups: L. rhamnosus (n = 20), B. longum (n = 20), or placebo (n = 20). Serum amino acids were analyzed using High-Performance Liquid Chromatography (LC).
  • Rigorous Journal
Alzheimer's disease (AD) is a neurodegenerative condition characterized by cognitive decline and associated metabolic disturbances, including altered amino acid profiles. This study investigated the effects of probiotic supplementation with Lactobacillus rhamnosus HA-114 and Bifidobacterium longum R0175 on serum amino acid levels in adults with mild to moderate AD. In a 12-week, randomized, double-blind, placebo-controlled trial, 60 participants (aged 50-90 years) were assigned to three groups: L. rhamnosus (n = 20), B. longum (n = 20), or placebo (n = 20). Serum amino acids were analyzed using High-Performance Liquid Chromatography (LC). Changes in total amino acids, Branched Chain Amino Acids (BCAAs), and aromatic amino acids (AAAs) were assessed as the primary outcomes. A significant interaction effect was found between time and group for serum amino acids. Compared to placebo, the B. longum group showed a significant increase in total amino acids (difference: 2132.67 µmol/L, 95% CI: 464.06-3801.28; p = 0.01), BCAAs (difference: 255.15 µmol/L, 95% CI: 53.01-457.30; p = 0.01), and AAAs (difference: 374.34 ng/ml, 95% CI: 57.45-691.23; p = 0.02). The L. rhamnosus group also showed a significant increase in BCAAs compared to placebo (difference: 206.08 µmol/L, 95% CI: 3.94-408.23; p = 0.04). The greatest improvements were consistently observed in the B. longum group across all primary outcome measures. Probiotic supplementation, particularly with B. longum, significantly improved serum amino acid profiles in patients with mild to moderate Alzheimer's disease. These findings support the potential of specific probiotic strains to address metabolic imbalances in AD through gut-brain axis modulation. Trial Registration: IRCT number: 20210513051277N1 (2021-05-27).

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