Effects of Iranian propolis on glycemic status, inflammatory factors, and liver enzyme levels in type 2 diabetic patients: a randomized, double-blind, placebo-controlled, clinical trial

Objective: Propolis is one of the hive products with a wide clinical usage due to the variety of bioactive components. This clinical trial was conducted to evaluate the effects of propolis supplementation on glycemic status and inflammation. Methods: In an 8-week randomized, double-blinded, placebo-controlled, clinical trial, patients with type 2 diabetes were randomly assigned to the propolis (n = 31) or control group (n = 31). The first group received propolis capsules (500 mg), 3 times a day. Fasting blood samples were obtained. The liver enzymes, inflammatory markers, and glucose-related indicators were measured at the beginning and the end of the study. Results: Compared with the control group, the propolis group showed significant changes in fasting plasma glucose (propolis, -19.8  ±  29.16; placebo, 0.7  ±  27.8; p  =  0.01), two-hour postprandial glucose (propolis, -27.42  ±  44.5; placebo, -0.95 ± 42.7; p = 0.001), hemoglobin A1c (propolis, -1.07 ± 1.6; placebo, 0.03 ± 1.5; p = 0.041), insulin (propolis, -1.65 ± 4.3; placebo, 0.04 ± 4.02; p = 0.03), HOMA-IR (propolis, -1.08 ± 0.7; placebo, 0.03 ± 0.42; p = .044), TNF-α (propolis, -2.67  ±  4.1; placebo, 0.12  ±  4; p  =  0.025), and C-reactive protein (propolis, -2.5  ±  3.01; placebo, -0.67  ±  2.84; p  =  0.031). Furthermore, propolis reduced the mean aspartate aminotransferase (AST) (propolis, -1.62  ±  10.4; placebo, 0.13  ±  11.07; p  =  0.12) and alanine aminotransferase (ALT) levels (propolis, -0.61 ± 6.47; placebo, 0.12 ± 7.01; p = 0.54), but it was not significant. Conclusion: Propolis treatment in type 2 diabetic patients had a beneficial effect on the glycemic profile and inflammatory status. However, there was no significant change in the level of AST and ALT enzymes, warranting further research.