Table 2.
Effects of nutraceuticals in DR (clinical studies).
| Dietary Compound | Family of Compound | Type | Dosage | Supplementation Period | Candidates | Effects | Year | Refs. |
|---|---|---|---|---|---|---|---|---|
| Omega-3 PUFAs (DHA/EPA) | Oil | Prospective | 1 g omega-3 fatty acids (containing 460 mg EPA and 380 mg DHA) daily | 6.5 years | T1DM/T2DM with or without DR | No benefits for DR. | 2023 | [69] |
| DHA | Oil | Prospective | 1050 mg/day | 2 years | NPDR (any stage) | Did not appear to influence the slowing of the progression of NPDR | 2022 | [68] |
| Brudyretina: high rich DHA (1050 mg/d) nutraceutical formulation, (DHA, EPA, a mixture of B vitamins, vitamins C and E, lutein, zeaxanthin, and minerals) | Oil plus others | Prospective | 3 capsules of Brudyretina 1.5 g once daily | 90 days | T2DM with NPDR (24 patients) | No difference in BCVA and central subfield macular thickness. Total antioxidant capacity levels increased, and plasma IL-6 levels decreased | 2018 | [152] |
| Lutein | Carotenoids | Prospective | 10 mg/day of lutein | 36 weeks | T2DM with NPDR (30 patients) | Improved contrast sensitivity | 2017 | [95] |
| Lutein (L) and zeaxanthin (Z) | Carotenoids | Retrospective | Z (0.5 mg/day) or Z (0.5 mg/day) + L (6 mg/day) | 4 months | NPDR (72 patients) | Lutein supplement showed no benefits | 2019 | [97] |
| Lycopene | Carotenoids | Cross-sectional | Lycopene intake was assessed by using a food frequency questionnaire | / | T2DM patients and healthy controls | Ameliorated oxidative stress | 2021 | [96] |
| Anthocyanin | Polyphenol | Prospective | 320 mg/day | 4 weeks | Healthy controls; T2DM; T2DM-at-risk | Anti-inflammatory (IL-6, IL-18, TNF-α ↓) | 2021 | [110] |
| Curcumin, artemisia, bromelain, and black pepper | Combo | Prospective | Curcumin (200 mg), artemisia (80 mg), bromelain (80 mg), and black pepper (2 mg) | 6 months | T2DM with or without mild to moderate DME | Increased central retinal thickness, visual acuity, and vessel density of the deep capillary plexus | 2022 | [127] |
Abbreviations: BCVA, best-corrected visual acuity; DHA, docosahexaenoic acid; DME, diabetic macular edema; DR, diabetic retinopathy; EPA, eicosapentaenoic acid; IL-6, interleukin-6; IL-18, interleukin-18; NPDR, non-proliferative diabetic retinopathy; PUFA, polyunsaturated fatty acids; T1DM, type 1 diabetes mellitus; T2DM, type 2 diabetes mellitus; TNF-α, tumor necrosis factor-alpha; ↓: down-regulated.