Table 1.

Characteristics of studies reporting on resveratrol supplementation in patients with type 2 diabetes on hypoglycemic therapy.

Author, Year	Country	Sample Size Average Age (% Male)	Experimental Model, Dose Used, and Intervention Period	Experimental Outcome and Proposed Mechanism
Bhatt et al., 2012 [24]	India	Total = 57 (n = 29 controls/n = 28 intervention) Average age = 57 (37%)	Type 2 diabetic (T2D) patients, on minimum of 6 months of ongoing oral hypoglycemic treatment (metformin and/or glibenclamide), received resveratrol at 250 mg/daily for 3 months	Supplementation with resveratrol significantly improved the mean glycated hemoglobin (HbA1c), systolic blood pressure, and total protein in T2D. No significant changes in body weight and high-density lipoprotein and low-density lipoprotein cholesterols
Movahed et al., 2013 [26]	Iran	Total = 66 (n = 33 controls/n = 33 intervention) Average age = 52 (50%)	T2D patients, on metformin therapy received resveratrol at a dose 1 g/day for 1½ months and a control group which received placebo tablets	Resveratrol treatment significantly decreased systolic blood pressure, fasting blood glucose, hemoglobin A1c, insulin, and insulin resistance, while high-density lipoprotein was significantly increased when compared to their baseline levels. Liver and kidney function markers were unchanged in the intervention group
Goh et al., 2014 [39]	Singapore	Total = 10 (n = 5 controls/n = 5 intervention) Average = 56 (100%)	T2D patients, oral hypoglycemic agents, received resveratrol at a dose of 3 g or placebo for 3 months	Resveratrol regulated energy expenditure through increased skeletal muscle NAD-dependent deacetylase sirtuin-1 (SIRT1) and 5′ AMP-activated protein kinase (AMPK) expression
Bo et al., 2016 [38]	Italy	Total = 192 (n = 62 control/n = 130 intervention) Average age = 65 (66%)	T2D patients received resveratrol supplementation at two different dosages (500 and 40 mg/day) for 6 months, of which 67.7% were on metformin	Treatment did not affect body weight, body mass index, waist circumference, and values of arterial blood pressure, fasting glucose, glycated hemoglobin, insulin, C-peptide, free fatty acids, liver transaminases, uric acid, adiponectin, and interleukin-6, in both the Resv500 and Resv40 arms vs. placebo. Total cholesterol and triglycerides slightly increased with resveratrol treatment
Timmers et al., 2016 [37]	The Netherlands	Total = 17 Average age = 64 (100%)	T2D patients treated with placebo and 150 mg/day resveratrol and average metformin dose of 2188 mg/day in a randomized double-blind crossover study for 1 month	Hepatic and peripheral insulin sensitivity were not affected by resveratrol treatment. Resveratrol also significantly improved ex vivo mitochondrial function
Seyyedebrahimi et al., 2018 [40]	Iran	Total = 46 (n = 23 controls/n = 23 intervention) Average age = 57 (86%)	T2D patients received resveratrol supplementation or placebo at a dose of 800 mg/day for 2 months	Resveratrol reduced plasma protein carbonyl content and significantly increased plasma total antioxidant capacity and total thiol content. However, it had no effect on metabolic parameters