A Meta-Analysis of the Impact of Resveratrol Supplementation on Markers of Renal Function and Blood Pressure in Type 2 Diabetic Patients on Hypoglycemic Therapy

This was a meta-analysis of five studies including 388 adults with type 2 diabetes receiving hypoglycemic therapy, mainly metformin-based regimens. Across the included trials, 56% of participants received resveratrol and 44% received placebo; reported active-arm sizes included 28 participants in Bhatt et al. and 33 participants in Movahed et al.

Oral resveratrol supplementation was tested across five trials in varying doses and durations. One active arm received 250 mg/day for 3 months, and another used 1 g/day for 1.5 months; dosing for one included trial was not specified in the provided text.

Resveratrol produced a clear reduction in systolic blood pressure, but glycemic and renal effects were inconsistent overall. Pooled effects were not significant for fasting glucose (SMD = -0.06, 95% CI: -0.24, 0.12), insulin (SMD = -0.08, 95% CI: -0.50, 0.34), or HbA1c (SMD = 0.18, 95% CI: -0.17, 0.52), and renal markers were mostly null, including creatinine (SMD = 0.13, 95% CI: -0.15, 0.40) and uric acid (SMD = -0.25, 95% CI: -0.56, 0.06). Systolic blood pressure decreased significantly (SMD = -5.77, 95% CI: -8.61, -2.93; p = 0.02), while total protein showed a small decrease (SMD = -0.19, 95% CI: -0.36, -0.02; p = 0.001).

The evidence base was small, with only five trials and heterogeneous dosing regimens and durations. Several outcomes showed substantial inconsistency across studies, including insulin, HbA1c, diastolic blood pressure, and total protein, and renal outcomes were not convincingly improved. Follow-up was short and one trial dose was not specified, limiting confidence in long-term renal conclusions.