Brasnyó 2011.

Methods	Study design: parallel randomised controlled clinical trial
Participants	Inclusion criteria Over 18 years of age Previously diagnosed with type 2 diabetes (according to WHO diagnostic guidelines) Normal creatinine clearance ≥ 90 mL/min Willing to abstain from any alcoholic beverages and foods containing substantial amounts of resveratrol (e.g. wine, red grapes, peanuts, berries) Exclusion criteria Receiving insulin treatment Receiving corticosteroids Alcohol or drug abuse Severe liver or cardiac (New York Heart Association III or IV) disease Existing autoimmune disease Acute infection Any type of malignancy Diagnostic criteria: quote from publication: "A total of nineteen Caucasian male patients previously diagnosed with type 2 diabetes (according to the WHO diagnostic guidelines) were included in the study" Setting: outpatients Age group: adults Gender distribution: males Country where study was performed: Hungary
Interventions	Intervention(s): trans‐resveratrol Comparator(s): placebo Duration of intervention: 4 weeks Duration of follow‐up: 4 weeks Run‐in period: 4 weeks Number of study centres: 1 Extension period: none
Outcomes	Reported outcome(s) in full text of publication: insulin resistance/sensitivity, creatinine normalised ortho‐tyrosine level in urine samples (as a measure of oxidative stress), incretin levels, and phosphorylated protein kinase B (pAkt):protein kinase B (Akt) ratio in platelets
Study details	Trial identifier: none Study terminated early: no
Publication details	Language of publication: English Funding: "The present study received no specific grant from any funding agency in the public, commercial or not‐for‐profit sectors" Publication status: peer‐reviewed journal
Stated aim for study	Quote from publication: "To determine whether the polyphenol resveratrol improves insulin sensitivity in type 2 diabetic patients and to gain some insight into the mechanism of its action"
Notes	"Resveratrol of herbal origin (with > 98% t‐resveratrol content) and the placebo (both in gelatin capsules) were obtained from Argina Nutraceuticals (previously Admarc Nutraceuticals, Fót, Hungary) and dosed 5 mg/capsule. The identical placebo capsules contained only the carrier microcrystalline cellulose" "The general examination was followed by a 4‐week washout period before the trial began (during which all lipid‐lowering medication was ceased)"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote from publication: "They underwent a blinded randomisation into two groups: ten patients to receive oral resveratrol twice daily (in gelatin capsules containing 5 mg resveratrol) and nine patients to placebo"
Allocation concealment (selection bias)	Unclear risk	Comment: not reported
Blinding of participants and personnel (performance bias) adverse events	Low risk	Quote from publication: "nineteen patients enrolled in the 4‐week long double‐blind study were randomly assigned into two groups" "The identical placebo capsules contained only the carrier microcrystalline cellulose"
Blinding of participants and personnel (performance bias) all‐cause mortality	Low risk	Quote from publication: "nineteen patients enrolled in the 4‐week long double‐blind study were randomly assigned into two groups" "The identical placebo capsules contained only the carrier microcrystalline cellulose"
Blinding of participants and personnel (performance bias) insulin sensitivity	Low risk	Quote from publication: "nineteen patients enrolled in the 4‐week long double‐blind study were randomly assigned into two groups" "The identical placebo capsules contained only the carrier microcrystalline cellulose"
Blinding of outcome assessment (detection bias) adverse events	Unclear risk	Comment: not reported
Blinding of outcome assessment (detection bias) all‐cause mortality	Low risk	Comment: not reported; outcome measure unlikely influenced by potential lack of blinding
Blinding of outcome assessment (detection bias) insulin sensitivity	Low risk	Comment: not reported; outcome measure unlikely influenced by potential lack of blinding
Incomplete outcome data (attrition bias) adverse events	Low risk	Comment: no missing data
Incomplete outcome data (attrition bias) all‐cause mortality	Low risk	Comment: no missing data
Incomplete outcome data (attrition bias) insulin sensitivity	Low risk	Comment: no missing data
Selective reporting (reporting bias)	Unclear risk	Comment: protocol not available
Other bias	Low risk	Comment: none detected