Evidence map›Paper›PMID 23507223›Full record

Trial reportNutrition research (New York, N.Y.)2013

Green tea supplementation increases glutathione and plasma antioxidant capacity in adults with the metabolic syndrome.

Arpita Basu, Nancy M Betts, Afework Mulugeta, Capella Tong, Emily Newman, Timothy J Lyons

Open access · greenAbstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Nutrition research (New York, N.Y.), 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 48 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
48citing papers in PubMed, 2 pooled it
5.8field-weighted citation impact, top 4% of its field
1 · What the graph read from 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.

2 · The registry

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.

3 · Its place in the literature

Who cites it

48 citing papers in PubMed, 2 syntheses or guidelines pooled it, 109 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Trial
  4. Trial
  5. Trial
  6. Review
  7. Review
  8. Enhanced Effects of Complex Tea Extract and the Postbiotic BPL1International journal of molecular sciences · 2026
    Article
  9. Article
  10. Article
  11. Article
  12. Article
  13. Article
  14. How to Increase Cellular Glutathione.Antioxidants (Basel, Switzerland) · 2023
    Review
  15. Article
  16. Observational
  17. Article
  18. Review
  19. Review
  20. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors at 2 institutions in 1 country.

Arpita BasuNutritional Sciences, 301 Human Sciences, Oklahoma State University, Stillwater, OK 74078-6141, USA. arpita.basu@okstate.edu
Nancy M Betts
Afework Mulugeta
Capella Tong
Emily Newman
Timothy J Lyons
Oklahoma State University · USUniversity of Oklahoma Health Sciences Center · US

Funding

THE ROLE OF COMPLEX 1 IN MITOCHONDRIAL DYSFUNCTION & FREE RADICAL PROD IN TYPE 1P20RR024215 · NCRR · UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR · PI SHORT, KEVIN R. · 2007 to 2011
$11.7M
Trt. of Primary Hyperaldosteronism w/ACE Inhibitors &Angiotension Rec. BlockersM01RR014467 · NCRR · UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR · PI TUCKER, PHEBE M · 2001 to 2007
$10.4M
NCRR NIH HHS M01 RR014467NCRR NIH HHS M01-RR14467NCRR NIH HHS P20 RR 024215NCRR NIH HHS P20 RR024215
6 · The paper itself

Abstract

Green tea, a popular polyphenol-containing beverage, has been shown to alleviate clinical features of the metabolic syndrome. However, its effects in endogenous antioxidant biomarkers are not clearly understood. Thus, we tested the hypothesis that green tea supplementation will upregulate antioxidant parameters (enzymatic and nonenzymatic) in adults with the metabolic syndrome. Thirty-five obese participants with the metabolic syndrome were randomly assigned to receive one of the following for 8 weeks: green tea (4 cups per day), control (4 cups water per day), or green tea extract (2 capsules and 4 cups water per day). Blood samples and dietary information were collected at baseline (0 week) and 8 weeks of the study. Circulating carotenoids (α-carotene, β-carotene, lycopene) and tocopherols (α-tocopherol, γ-tocopherol) and trace elements were measured using high-performance liquid chromatography and inductively coupled plasma mass spectroscopy, respectively. Serum antioxidant enzymes (glutathione peroxidase, glutathione, catalase) and plasma antioxidant capacity were measured spectrophotometrically. Green tea beverage and green tea extract significantly increased plasma antioxidant capacity (1.5 to 2.3 μmol/L and 1.2 to 2.5 μmol/L, respectively; P < .05) and whole blood glutathione (1783 to 2395 μg/g hemoglobin and 1905 to 2751 μg/g hemoglobin, respectively; P < .05) vs controls at 8 weeks. No effects were noted in serum levels of carotenoids and tocopherols and glutathione peroxidase and catalase activities. Green tea extract significantly reduced plasma iron vs baseline (128 to 92 μg/dL, P < .02), whereas copper, zinc, and selenium were not affected. These results support the hypothesis that green tea may provide antioxidant protection in the metabolic syndrome.

Indexed as

TeaAdultAntioxidantsCarotenoidsCatalaseDietary SupplementsGlutathioneGlutathione PeroxidaseHumansMetabolic SyndromeObesityPlant ExtractsSingle-Blind MethodTocopherolsTrace ElementsAntioxidantsCarotenoidsCatalaseGlutathioneGlutathione PeroxidasePlant ExtractsTeaTocopherolsTrace Elements

Identifiers

PMID23507223
PMCPMC3603270
OpenAlexW1975695659

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

None linked

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.