Table 3.
Clinical studies on the effects of dietary berry intervention (fresh or processed whole berries and juice) on glycemic control in adults with metabolic syndrome or pre-diabetes
| Reference (year) | Participants | Study design | Intervention | Significant findings |
|---|---|---|---|---|
| Xiao et al. (2019)77 | Adults with prediabetes and insulin resistance and overweight/obesity sample size: n = 32 | Randomized, single-blinded, crossover triple-arm postprandial meal study | Breakfast meal with frozen whole red raspberries 250 g (Tx1), 125 g (Tx2), or 0 g (Cx1) for 2h-postprandial study | ↓2-Hour insulin AUC in Tx1 and Tx2 ↓Peak insulin, peak glucose, and 2-hour glucose AUC in Tx2 vs. Cx1 ↓TGs in Tx1 vs. Tx2 |
| Espinosa-Moncada et al. (2018)74 | Adult females; nonpregnant; nonsmokers; with MetS; sample size: n = 40 | Randomized, double-blind, placebo-controlled, crossover parallel-arm study | Agraz (Vaccinium meridionale Swartz, Colombian blueberry) berry nectar 200 mL day−1 (Tx1); or polyphenol-free macronutrient and taste-matched placebo 200 mL day−1 (Cx1) for 12 weeks | ↓hsCRP, DNA oxidative damage and ↑antioxidant capacity in Tx1 vs. Cx1; no effects on markers of insulin resistance and BG |
| Kim et al. (2018)73 | Adults with MetS; sample size: n = 37 | Randomized, double-blind, placebo-controlled, parallel-arm study | Acai berry beverage 325 mL day−1 (Tx1); or flavor-matched placebo beverage (Cx1) for 12 weeks | ↓IFN-γ and 8-isoprostane in Tx1; no effects on markers of insulin resistance and BG |
| Hanhineva et al. (2014)103 | Adults with MetS; sample size: n = 106 | Randomized, triple-arm study | Dietary intervention including 300 g day−1 bilberries (Tx1); or healthy diet without berries (Tx2); or control diet (Cx1) for 12 weeks | ↓Glucuronidated alk(en)ylresorcinols; ↑plasma HA in Tx1 and Tx2 vs. Cx1; no effects on markers of insulin resistance and BG |
| Simão et al. (2013)71 | Adults with MetS; sample size: n = 56 | Placebo-controlled, parallel-arm study | Cranberry juice 0.7 L day−1 (Tx1); or control group on typical diet (Cx1) for 60 days | ↑Adiponectin, folic acid ↓Lipoperoxidation and protein oxidation; homocysteine with Tx1 vs. Cx1; no effects on insulin resistance and BG |
| Puupponen-Pimia et al. (2013)53 | Adults with a BMI 26–39 kg m−2 with features of MetS; sample size: n = 32 | Randomized, controlled, parallel-arm study | Strawberry puree 100 g day−1 + raspberries 100 g day−1 + cloudberries 100 g day−1 (Tx1); or berry-free control group (Cx1) for 16 weeks | ↑Leptin concentration in Tx1; serum lipidomics revealed 20 discriminating lipids in Tx1 vs. Cx1; BG and insulin not reported |
| Basu et al. (2011)70 | Adults with MetS; sample size: n = 36 | Randomized, double-blind, placebo-controlled, parallel-arm study | Cranberry juice 480 mL day−1 (Tx1); or energy and flavor-matched placebo beverage (Cx1) for eight weeks | ↑Plasma antioxidant capacity and ↓oxidized LDL and malondialdehyde in Tx1 vs. Cx1; no effects on BG |
| De Mello et al. (2011)72 | Adults with features of MetS and impaired glucose control sample size: n = 104 | Randomized, placebo-controlled, parallel-arm study | Healthy diet with whole-grain replacement, fatty fish, and bilberries totaling 300 g day−1 fresh-equivalent (Tx1); or diet with whole-grain replacement only and unchanged fish & berry consumption (Tx2); or unchanged diet with avoidance of whole-grain products and berries and limited fatty fish intake (Cx1) for 12 weeks | ↓plasma E-selectin in Tx1 only ↓plasma hsCRP in Tx1 and Tx2 |
| Basu et al. (2010)20 | Adults with MetS; sample size: n = 48 | Randomized, placebo-controlled parallel-arm study | Blueberries 350 g day−1 fresh-equivalent (Tx1); or water control (Cx1) for eight weeks | ↓Systolic and diastolic BP, ox-LDL, MDA, HNE in Tx1 vs. Cx1; no effects on BG and insulin resistance |
| Basu et al. (2010)65 | Adults with MetS; sample size: n = 27 | Randomized, placebo-controlled, parallel-arm study | Strawberry, freeze-dried powder 50 g day−1 (∼3 cups fresh-equivalent) (Tx1); or water control (Cx1) for eight weeks | ↓Total- & LDL-C, small LDL particles, and plasma VCAM-1 in Tx1 vs. Cx1; no effects on BG |
AUC: Area under the curve, BG: blood glucose, BP: blood pressure, C: cholesterol, Cx: control group, HA: hippuric acid, HNE: hydroxynonenal, hsCRP: high-sensitivity C-reactive protein, IFN: interferon, LDL: low-density lipoprotein, MDA: malondialdehyde, MetS: Metabolic Syndrome, TG: triglycerides, Tx: treatment group, VCAM: vascular cell adhesion protein.