ArticleNutrition research and practice2021
Effects of poly-gamma-glutamic acid and vitamin B
Article in Nutrition research and practice, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
6 citing papers in PubMed, 1 synthesis or guideline pooled it, 9 citations in OpenAlex.
- Dietary Supplement Interventions and Sleep Quality Improvement: A Systematic Review and Meta-Analysis.Nutrients · 2025Pooled it
- Association between methyl donor nutrients intake with sleep duration, sleep quality and biomarkers of oxidative stress and inflammation among adults.Nutrition journal · 2026Article
- Consumption of poly-γ-glutamate-vitamin B6 supplement and urinary microbiota profiles in Korean healthy adults: a randomized, double-blinded, placebo-controlled intervention study.Nutrition research and practice · 2024Article
- From Garden to Pillow: Understanding the Relationship between Plant-Based Nutrition and Quality of Sleep.Nutrients · 2024Review
- Oral Administration of Human-Gut-DerivedMicroorganisms · 2023Article
- Association of Pyridoxal 5'-Phosphate with Sleep-Related Problems in a General Population.Nutrients · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
2 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
BACKGROUD/
objectivesData regarding the effects of poly-γ-glutamic acid (γ-PGA) on sleep status are limited. This study aimed to test whether γ-PGA and vitamin B SUBJECTS/
methodsA factorial randomized, double-blinded, placebo-controlled crossover study included 47 adults (25 men and 22 women) who were free of chronic disease. Stratified randomized allocation considered age and gender for three interventions, group A (supplementation with γ-PGA 600 mg; n = 16), group B (supplementation with VitB6 100 mg; n = 14), and group C (dual supplementation of both γ-PGA 600 mg and VitB6 100 mg; n = 17). Participants underwent a 1-mon intervention period, followed by a 1-mon washout period, and then a second 1-mon intervention period. Differences (mean ± SD) in nighttime sleep status before and after supplementation were compared between the placebo and intervention groups using nonparametric tests.
resultsSignificant changes in sleep duration (0.27 ± 0.98 h,
conclusionsOn the basis of these findings, the dual supplementation of γ-PGA and VitB6 may be effective as functional food components to improve nighttime sleep status.
trial registrationClinical Research Information Service Identifier: KCT0005083.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.