Table 2.
Intervention studies of various polyphenols on glycemic control andmetabolic parameters
| Sources/types of flavonoids (dose) | Subject | Duration of intervention | Result | Comment | Reference |
|---|---|---|---|---|---|
| Purified anthocyanins capsules from natural bilberry and blackcurrant (320 mg/d) | Prediabetes, early untreated T2DM | 12 wk | FBG: no change HbA1c: decrease Insulin: no change TC and TG: no change HDL-C and LDL-C: decrease |
Significant differences were observed in the net changes of HbA1c and LDL-C between anthocyanin and placebo groups | Yang et al. (2017) |
| Resveratrol capsules (480 mg/d) | T2DM | 4 wk | FBG: no change Insulin: decrease HOMA-IR: decrease TG: no change |
FBG and TG in resveratrol group did not differ significantly from placebo Insulin level at post-intervention was significantly different in resveratrol compared to placebo groups |
Zare Javid et al. (2017) |
| Resveratrol capsules (800 mg/d) | T2DM | 8 wk | FBG: decrease HbA1c: no change Insulin: decrease HOMA-IR: decrease HDL-C: decrease TC and TG: no change LDL-C: decrease |
There was significant difference in FBG found in resveratrol group compared with placebo No mean difference of HDL-C levels between resveratrol and placebo groups |
Khodabandehloo et al. (2018) |
| Resveratrol capsules (1,000 mg/d) | T2DM | 8 wk | FBG: decrease HbA1c: no change Insulin: decrease HOMA-IR: decrease TC, TG, and LDL-C: no changes HDL-C: increase |
Study included overweight participants with body mass index 25~30 kg/m2 with HbA1c <8% | Abdollahi et al. (2019) |
| BPF powder (650 mg/d) or BPF phytosome formulation (500 mg/d) | T2DM | 30 d | FBG: decrease TC, TG, and LDL-C: decrease HDL-C: increase |
No significant changes found in placebo group for FBG, TC, TG, LDL-C, and HDL-C No statistically significant differences detected between BPF and BPF Phyto groups on their hypoglycemic and hypolipemic effect |
Mollace et al. (2019) |
| Freeze-dried blueberries (22 g/d, contain 262 mg anthocyanins) | T2DM | 8 wk | HbA1c and TG were significantly lower in freeze-dried blueberries than placebo groups | TC, TG, and LDL-C between groups treated with freeze-dried blueberries and placebo were significantly different | Stote et al. (2020) |
| Purified anthocyanins capsules from natural bilberry and blackcurrant (320 mg/d) | Prediabetes, newly diagnosed untreated T2DM | 12 wk | FBG: no change HbA1c: decrease HOMA-IR: no change TC and TG: no change HDL-C and LDL-C: decrease |
Study included participants with HbA1c 5.7%~6.4% There was significant difference in HbA1c found between anthocyanin and placebo groups No significant net change in TC, TG, HDL-C, and LDL-C between anthocyanin and placebo groups |
Yang et al. (2021) |
| Powdered anthocyanins capsules from natural bilberry and blackcurrant (320 mg/d) | T2DM-at-risk, T2DM | 4 wk | FBG: decrease LDL-C: decrease TC, TG, and HDL-C: no change |
FBG and LDL-C was significantly reduced after intervention within T2DM-at-risk group but not in T2DM group | Nikbakht et al. (2021) |
| Resveratrol capsules (1,000 mg/d) | T2DM | 5 wk (crossover) | There were no significant differences in FBG and HbA1c between resveratrol and placebo treatments | Study included T2DM patients on diet control alone | Thazhath et al. (2016) |
T2DM, type 2 diabetes mellitus; FBG, fasting blood glucose; HbA1c, hemoglobin A1c; TC, total cholesterol; TG, triglyceride; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; HOMA-IR, homeostatic model assessment for insulin resistance; BPF, Bergamot polyphenolic fraction.