Table 1.
Study characteristics and most common biomarkers of oxidative stress reported by the 28 randomized controlled trials 1.
| Study Characteristics | Total | Antioxidants | Isoprostanes | MDA | OxLDL |
|---|---|---|---|---|---|
| n | 28 | 19 | 9 | 7 | 7 |
| Study design, n (% of studies) | |||||
| Parallel | 19 (68%) | 12 (63%) | 6 (67%) | 5 (71%) | 5 (71%) |
| Crossover | 9 (32%) | 7 (37) | 3 (33%) | 2 (29%) | 2 (29%) |
| Blinding | |||||
| Double-blind | 18 (64%) | 12 (63%) | 8 (89%) | 3 (43%) | 4 (57 %) |
| Single-blind | 4 (14%) | 2 (11%) | 1 (11%) | 2 (29%) | 1 (14%) |
| Not blinded | 3 (11%) | 2 (11%) | 0 (0%) | 2 (29%) | 2 (29%) |
| Unclear | 3 (11%) | 3 (15%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Region, n (% of studies) | |||||
| Asia | 1 (4%) | 1 (5%) | 0 (0%) | 0 (0%) | 0 (0%) |
| New Zealand | 1 (4%) | 1 (5%) | 0 (0%) | 1 (14%) | 0 (0%) |
| Europe | 9 (32%) | 5 (26%) | 3 (33%) | 2 (29%) | 3 (43%) |
| North America | 10 (36%) | 6 (32%) | 5 (56%) | 1 (14%) | 4 (57%) |
| South America | 4 (14%) | 4 (21%) | 1 (11%) | 1 (14%) | 0 (0%) |
| Middle East | 3 (11%) | 2 (11%) | 0 (0%) | 2 (29%) | 0 (0%) |
| Sample size, n (% of studies) | |||||
| 10–20 | 4 (14%) | 3 (15%) | 1 (11%) | 1 (14%) | 1 (14%) |
| 21–30 | 3 (11%) | 3 (15%) | 0 (0%) | 1 (14%) | 0 (0%) |
| 31–50 | 12 (43%) | 7 (38%) | 4 (44%) | 2 (29%) | 3 (43%) |
| 51–100 | 7 (25%) | 4 (21%) | 3 (33%) | 3 (43%) | 3 (43%) |
| >100 | 2 (7%) | 2 (11%) | 1 (11%) | 0 (0%) | 0 (0%) |
| Intervention duration, n (% of studies) | |||||
| ≥1 week to 4 weeks | 7 (25%) | 3 (15%) | 1 (11%) | 1 (14%) | 1 (14%) |
| >1 month to 3 months | 20 (71%) | 12 (64%) | 7 (78%) | 6 (86%) | 5 (71%) |
| >3 months | 1 (4%) | 4 (21%) | 1 (11%) | 0 (0%) | 1 (14%) |
| Mean age, n (% of studies) | |||||
| <50 years | 16 (57%) | 10 (53%) | 6 (67%) | 5 (71%) | 2 (29%) |
| ≥50 years | 12 (43%) | 9 (47%) | 3 (33%) | 2 (29%) | 5 (71%) |
| Baseline health, n (% of studies) | |||||
| Healthy | 10 (36%) | 7 (38%) | 3 (33%) | 4 (57%) | 3 (43%) |
| At-risk | 18 (64%) | 12 (62%) | 6 (67%) | 3 (43%) | 4 (57%) |
| Weight status, n (% of studies) | |||||
| Normal weight: BMI 18.5 kg/m² and 25 kg/m² | 7 (25%) | 5 (26%) | 0 (0%) | 3 (43%) | 1 (14%) |
| Overweight: BMI 25 kg/m² and 29.9 kg/m² | 13 (46%) | 10 (53%) | 5 (56%) | 3 (43%) | 3 (43%) |
| Obese: BMI 30 kg/m² or higher | 8 (29%) | 4 (21%) | 4 (44%) | 1 (14%) | 3 (43%) |
| Intervention, n (% of studies) | |||||
| Acai | 3 (11%) | 2 (11%) | 1 (11%) | 1 (14%) | 0 (0%) |
| Agraz | 2 (7%) | 2 (11%) | 1 (11%) | 0 (0%) | 0 (0%) |
| Aronia (Chokeberry) | 3 (11%) | 2 (11%) | 2 (22%) | 0 (0%) | 1 (14%) |
| Bilberry | 2 (7%) | 2 (11%) | 0 (0%) | 0 (0%) | 1 (14%) |
| Blackcurrant | 3 (11%) | 2 (11%) | 1 (11%) | 1 (14%) | 0 (0%) |
| Blueberry | 6 (21%) | 5 (26%) | 1 (11%) | 1 (14%) | 1 (14%) |
| Cranberry | 3 (11%) | 2 (11%) | 2 (22%) | 0 (0%) | 1 (14%) |
| Maqui berry | 1 (4%) | 0 (0%) | 1 (11%) | 0 (0%) | 1 (14%) |
| Pomegranate | 1 (4%) | 1 (5%) | 0 (0%) | 1 (14%) | 0 (0%) |
| Strawberry | 1 (4%) | 0 (0%) | 0 (0%) | 1 (14%) | 0 (0%) |
| Whortleberry | 1 (4%) | 0 (0%) | 0 (0%) | 1 (14%) | 0 (0%) |
| Mixed berries | 2 (7%) | 1 (5%) | 0 (0%) | 1 (14%) | 2 (29%) |
1 Values of 0 (0%) show potential gaps in the literature, where no randomized controlled trial met the provided study characteristic. Abbreviations: MDA, malondialdehyde; Ox-LDL, oxidized low-density lipoprotein.