Propolis is a natural resin collected by honeybees from various plants. Bees mix it with their saliva and wax to seal holes, smooth honeycomb walls, and protect their hive entrance. Propolis has been valued for its biological and antioxidant properties in traditional medicine since at least 300 BC (1).
The complex chemical composition of propolis varies based on the plants and environment from which it is collected, making standardization difficult. Propolis generally contains a mixture of phenols, terpenes, amino acids, vitamins, sugars, and elements. Despite differences in composition across regions, propolis samples tend to have comparable pharmacological properties (1).
Many studies have shown that propolis has numerous medicinal properties, including antimicrobial, immune-boosting, antitumor, anti-inflammatory, antioxidant, antiviral, and antifungal effects. It also protects the liver, kidneys, and pancreas. Recent research indicates propolis can help lower blood sugar and improve diabetes complications. It may also regulate blood lipid levels, reduce lipid peroxidation, and scavenge free radicals. Its broad range of biological activities, safety, and long history of use make propolis a promising clinical drug (1).
A double-blind, placebo-controlled clinical trial was conducted to evaluate the effect of Iranian propolis extract on glucose metabolism, Lipid profile, Insulin resistance, renal and liver function as well as inflammatory biomarkers in patients with type 2 diabetes mellitus. Patients with type 2 diabetes were randomly assigned to a propolis group (1000 mg/day) (n = 50) or a placebo group (n = 44) for 90 days (2).
There was a significant decrease in the serum levels of glycosylated hemoglobin (HbA1c), 2-hour postprandial blood glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), homeostasis model assessment of β-cell function (HOMA-β). On day 90 the propolis group had a 11% reduction in HbA1c from 8.65 ± 1.24 to 7.67 ± 1.27 (%, p < 0.001) and a 45% reduction in insulin levels from 14.03 ± 15.43 to 7.61 ± 6.69 (μIU/ml, p = 0.001) compared to the data before propolis administration. Also, the placebo group showed a 32.93% increase in 2-hour postprandial blood glucose level from 168 .05±52.61 to 223.39 ± 82.04 (mg/dL, p < 0.0001) by the end of the study. The fasting blood glucose levels were not statistically different between the groups (2).
After the administration of propolis, the mean HDL-cholesterol level was significantly increased compared to the placebo group by 10.6% (p = 0.024). The propolis group had a 9.5% increase in HDL-cholesterol at day 90 from 44.66 ± 8.69 to 48.91 ± 9.32 (mg/dL, p < 0.0001) compared to the baseline. There were no statistically significant differences in total cholesterol, LDL-cholesterol, triglyceride, and VLDL in both groups (2).
The oxidative stress markers such as High sensitive C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), and liver transaminase (ALT and AST) and blood urea nitrogen (BUN) concentrations in the propolis group were also significantly reduced. These results showed that Iranian propolis had beneficial effects on reducing post-prandial blood glucose, serum insulin, insulin resistance, and inflammatory cytokines, and suggested that propolis could be a useful treatment for preventing liver and renal dysfunction and elevating HDL-cholesterol concentrations in patients with diabetes (2).
The effect of oral propolis supplementation on blood glucose, insulin resistance, and antioxidant status in type 2 diabetes was assessed in a randomized, double-blinded, placebo-controlled trial for 8 weeks. Sixty-two patients with type 2 diabetes (30-55 years of age) were randomly assigned to two groups, propolis (n = 31) and placebo (n = 31). Patients were given doses of 500 mg, three times a day (1500 mg), of propolis or a placebo three times a day (3).
After two months, fasting blood sugar (from 143.2±29 to 122.5±26.1 mg/dL), 2-hour postprandial glucose (from 192.7±85.3 to 165.3±76.8 mg/dL), insulin (from 11.9±2.7 to 10.2±2.5 mU/ml), insulin resistance (from 4.2±0.3 to 3.1±0.2), and HbA1c (from 7.7±1.6 to 6.6±1.5 %) were significantly decreased in patients treated with propolis compared with the placebo group with fasting blood sugar (from 145.6± 23.4 to 146.3± 29.9 mg/dL)(p < 0.05), 2-hour postprandial glucose (from 198.1±86.1 to 197.1±63.1 mg/dL), insulin (from 12.1±2.3 to 12.2±2.8 mU/ml), insulin resistance (from 4.4±0.2 to 4.4±0.3), and HbA1c (from 7.8±1.4 to 7.8±1.6 %). Additionally, intake of propolis significantly increased the blood levels of total antioxidant capacity and activity of glutathione peroxidase and superoxide dismutase (p < 0.05) (3).
This study showed that Propolis treatment can be helpful as a diet supplement in patients with type 2 diabetes by improving glycemic status, reducing insulin resistance, and enhancing antioxidant status (3).
A randomized clinical trial involved 66 patients with type 2 diabetes, who were randomly divided into two groups of intervention (propolis) and placebo. The Propolis group received 300 mg three times a day for a total of 900 mg/d of propolis pills, while the placebo group received pills with a similar look and composition but lacking propolis, on the same schedule for 12 weeks. Fasting blood glucose, hemoglobin A1c, total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride, serum insulin, and insulin resistance indices were the main outcome measures (4).
The mean change in fasting blood glucose between the propolis group, a 17.76 ± 27.72 mg/dL decrease, and that of the placebo group, a 6.48 ± 42.77 mg/dL increase was significantly different (p = 0.01). Change in mean hemoglobin A1c had a similar pattern to fasting blood glucose with a change of –0.77 ± 1.34 (%) for the propolis group and a change of + 0.19 ± 1.0 (%) for the placebo group (p<0.01). The mean change in total cholesterol between the propolis group 5.16 ± 43.80 mg/dL increase and the placebo group 28.9 ± 27.4 mg/dL increase was also significantly different (p = 0.01), suggesting the potential protective role of propolis against the increase in total cholesterol. The change in mean LDL was similar to the change in total cholesterol. There was no significant difference in other lipids or insulin resistance indices between the two groups. This study suggested that a daily intake of 900 mg of bee propolis supplement for 12 weeks could result in an improvement of glycemic and serum lipid levels in patients with type 2 diabetes (4).
A double-blind, randomized, placebo-controlled study evaluated the effect of propolis or metformin versus placebo on glycemic control in pharmacological treatment-naïve patients with type 2 diabetes mellitus. 36 pharmacological treatment-naïve patients with type 2 diabetes received propolis (300 mg, total 600 mg/day), metformin (850 mg), or a placebo twice daily before breakfast and dinner for 12 weeks (5).
The propolis and metformin groups exhibited significant reductions in fasting plasma glucose (p=0.009 and p=0.001, respectively), 2-h postprandial glucose (p=0.034 and p=0.001, respectively) levels, area under the curves (AUC) of insulin, Stumvoll index, and an increment in the Matsuda index. The comparison of the changes from baseline to the end showed significant differences in fasting plasma glucose (p=0.004) and hemoglobin A1c (p=0.049) levels between propolis and placebo groups. Between the metformin and placebo groups, there were differences in fasting plasma glucose (p=0.002), 2-h postprandial glucose (p=0.004), and A1C (p=0.007) levels (5).
The administration of propolis and metformin compared to placebo reduced fasting plasma glucose and A1C levels with the fasting plasma glucose levels from 7.3 ± 1.4 to 6.6 ± 0.9, from 8.0 ± 1.6 to 7.3 ± 1.1, and from 7.7 ± 1.2 to 8.2 ± 1.7 (mmol/L) in the propolis, metformin and placebo groups, respectively; and hemoglobin A1c levels from 6.6 ± 10.8 to 6.3 ± 0.9, from 6.8 ± 0.9 to 6.6 ± 0.8, and from 6.8 ± 0.9 to 7.0 ± 1.0 (%) in the propolis, metformin and placebo groups, respectively (p<0.05). In addition, compared to baseline, propolis, and metformin also decreased 2-h postprandial glucose levels with the levels from 14.6 ± 2.1 to 13.1 ± 1.9, from 15.8 ± 2.8 to 13.7 ± 2.7, and from 13.2 ± 1.9 to 13.2 ± 2.1 mmol/L in the propolis, metformin and placebo groups, respectively (p<0.05) (5).
The research findings on the effects of propolis on blood glucose levels indicate its potential benefits for patients with type 2 diabetes. Propolis supplementation led to significant reductions in glycosylated hemoglobin (HbA1c), postprandial blood glucose, insulin levels, and insulin resistance. Additionally, propolis was found to increase high-density lipoprotein (HDL) cholesterol levels and improve antioxidant status. These results suggest that propolis may have a positive impact on glycemic control, insulin sensitivity, and antioxidant capacity in individuals with type 2 diabetes.
References:
1. Anvarifard, P., Anbari, M., Ostadrahimi, A., Ardalan, M., & Ghoreishi, Z. (2022). A comprehensive insight into the molecular and cellular mechanisms of the effects of Propolis on preserving renal function: A systematic review. Nutrition & Metabolism, 19. https://doi.org/10.1186/s12986-021-00639-z
2. Zakerkish, M., Jenabi, M., Zaeemzadeh, N., Hemmati, A. A., & Neisi, N. (2019). The Effect of Iranian Propolis on Glucose Metabolism, Lipid Profile, Insulin Resistance, Renal Function and Inflammatory Biomarkers in Patients with Type 2 Diabetes Mellitus: A Randomized Double-Blind Clinical Trial. Scientific Reports, 9. https://doi.org/10.1038/s41598-019-43838-8
3. Afsharpour F, Javadi M, Hashemipour S, Koushan Y, Haghighian HK. Propolis supplementation improves glycemic and antioxidant status in patients with type 2 diabetes: A randomized, double-blind, placebo-controlled study. Complement Ther Med. 2019 Apr;43:283-288. doi: 10.1016/j.ctim.2019.03.001. Epub 2019 Mar 2. PMID: 30935545.
4. Samadi N, Mozaffari-Khosravi H, Rahmanian M, Askarishahi M. Effects of bee propolis supplementation on glycemic control, lipid profile and insulin resistance indices in patients with type 2 diabetes: a randomized, double-blind clinical trial. J Integr Med. 2017 Mar;15(2):124-134. doi: 10.1016/S2095-4964(17)60315-7. PMID: 28285617.
5. Ochoa-Morales PD, González-Ortiz M, Martínez-Abundis E, Pérez-Rubio KG, Patiño-Laguna ADJ. Anti-hyperglycemic effects of propolis or metformin in type 2 diabetes mellitus. Int J Vitam Nutr Res. 2023 Dec;93(6):498-506. doi: 10.1024/0300-9831/a000760. Epub 2022 Aug 15. PMID: 35965421.
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