Table 2 Summary of human studies on the CVD protective effects of blueberries
S/N | Interventions | Subjects/size | Dose | Study duration | Main findings | References |
|---|---|---|---|---|---|---|
1. | Randomized, control, cross-over dietary intervention trial | A group of 20 men and women aged ≥60 years | 250 mg blueberry mousse containing at least 300 mg anthocyanins versus control drink containing fructose, glucose and blueberry saccharose. | One (1) day intervention separated by 1-week washout. | 1. Reported protocols on vascular function, oxidative stress, and inflammation. | Del Bo et al. 2022 |
2. | A parallel, double-blind randomized clinical intervention trial | Forty-five (45) adult men with metabolic syndromes | 26 g (freeze-dried) blueberries (1 cup/150 g fresh blueberries) | 24 hours acute intervention | 1. Improved postprandial levels of glucose, insulin, total cholesterol, HDL-C, L-HDL-P, XL-HDL-P and Apo-A1 but not LDL-C, TG, or Apo-B. 2. No effects were observed for FMD, PWV, AIx and BP. | Curtis et al. 2022 |
3. | A cross-over randomized controlled intervention trial | Thirty-seven (37) participants | 160 g of fresh whole blueberry or 20 g of freeze-dried blueberry | One (1) week treatment followed by 1 week wash out | 1. Improved plasma NO2- levels 2. No effects SBP, DBP, total cholesterol, HDL-C, LDL-C, TAG, or glucose | Wang et al. 2022 |
4. | Randomized cross-over design intervention | Ten (10) adult males | 348 mg anthocyanins. | Ten (10) days | 1. Reduced H2O2-induced DNA 2. No differences in endogenous DNA damage, peripheral arterial function, and nitric oxide levels. | Del Bo et al. 2013 |
5. | Randomized-controlled study intervention | Forty-eight (48) participants (4 males and 44 females | 50 g freeze-dried blueberries (350 g fresh blueberries). | Eight (8) weeks. | 1. Decrease systolic and diastolic blood pressures 2. Decreased plasma oxidized LDL 3. Decreased serum malondialdehyde and hydroxynonenal concentration 4. No effect on serum glucose levels 5. No effect on lipid profiles. | |
6. | Double-blind, parallel placebo controlled randomized clinical trial intervention | One hundred and fifteen (115) males | 75 g and 150 g blueberries (1/2 cup and 1 cup respectively). | Six (6) months | 1. 1 cup improved endothelial function, systemic arterial stiffness and attenuated cyclic guanosine monophosphate concentrations. 2. ½ cup had no effect on these biomarkers. | Curtis et al. 2019 |
7. | Randomized, Double-Blind, Placebo-Controlled Clinical Trial. | Forty-four (44) adults | 45 g of blueberry | Six (6) weeks | 1. No difference in blood pressure and insulin sensitivity 2. Improved endothelial function. | Stull et al. 2015 |
8. | Randomized cross-over design interventions. | Fourteen (14) participants | 75 g and 35 g | Three (3) weeks. | 1. Decreased serum markers of oxidation 2. Improved antioxidant protection. | Blacker et al. 2013 |
9. | Randomized, double-blind, placebo-controlled clinical trial interventions. | Forty-eight (48) postmenopausal women with pre- and stage 1-hypertension | 22 g freeze-dried blueberry powder | Eight (8) weeks. | 1. Lowered systolic blood pressure and diastolic blood pressure and brachial-ankle PWV. 2. Improved nitric oxide levels. | Johnson et al. 2015 |
10. | Randomized cross-over design intervention. | Eighteen (18) male volunteers | 25 g freeze-dried powder (375 mg of ACNs). | Six (6) weeks, spaced by a 6-week wash-out period. | 1. Reduced levels of endogenously oxidized DNA bases and H2O2-induced DNA damage 2. No effect on markers of endothelial function. | Riso et al. 2013 |
11. | Double-blind, parallel-arm, randomized controlled trial intervention. | Fifty-two (52) men (US veterans) | 22 g freeze-dried blueberries | Eight (8) weeks. | 1. Lowered mean hemoglobin A1c, fructosamine, triglycerides, aspartate transaminase, and alanine transaminase 2. No effects on fasting plasma glucose, serum insulin, total cholesterol, LDL-cholesterol, HDL-cholesterol, and C-reactive protein levels, blood pressure, and body weight. | Stote et al. 2020 |
12. | A randomized controlled study intervention. | Twenty-five (25) subjects | 250/375 g blueberry | Six (6) weeks | 1. Decreased F2-isoprostanes and 5-OHMU 2. Increased plasma IL-10 and NK cell counts 3. Other markers were unaffected. | McAnulty et al. 2011 |
13. | Randomized, parallel-arm, double-blind, placebo-controlled clinical trial intervention. | Forty (40) pre- and stage 1-hypertensive postmenopausal women | 22 g freeze-dried highbush blueberry powder per day. | Eight (8) weeks. | 1. Reduced levels 8-hydroxy-2-deoxyguanosine (8-OHdG 2. Other biomarkers were unaffected | Johnson et al. 2017 |
14. | Randomized, controlled crossover trial intervention. | Ten (10) healthy volunteers | 34 g, freeze-dried powder equivalent to 240 g of fresh blueberry. | One (1) day intervention separated by 1-week washout. | 1. No differences in FMD 2. Differences in the levels of individual plasma metabolites. | |
15. | Randomized, controlled, double-blind, crossover human intervention trials. | Twenty-one (21) healthy men | 0, 766, 1278 and 1791 mg total blueberry polyphenol | One (1) day intervention with hourly measurements for 6 hours. | 1. Increased FMD 2. Decreased neutrophil NADPH oxidase. | Rodriguez-Mateos et al. 2013 |
16. | Randomized placebo-controlled crossover trial intervention | Twenty-three (23) volunteers | 24.1 g and 48.2 g respectively blueberry powder. | Three (3) days and 2-weeks washout period. | 1. No effects on plasma FFA and cytokine levels 2. Suppressed cytokines (IL-β, IL-6) production. | Ono-Moore et al. 2016 |
17. | Randomized controlled trial intervention. | Twenty-four (24) overweight and obese children | 375 g/week, blueberry purée. | Eight (8) study duration. | 1. Increased antioxidant levels 2. Reduced chronic markers of inflammation. | Giongo et al. 2011 |
18. | Randomized placebo-controlled study intervention. | Twenty-five men and postmenopausal women | 250 g blueberries. | Six (6) weeks duration. | 1. No effects on body mass, composition, and overall blood pressures 2. Decreased AIx and ASPs. 3. No effect on plasma redox 4. Increased absolute NK cells. | McAnulty et al. 2011 |
19. | Single-blind, randomized, placebo-controlled, crossover design trial intervention. | Nineteen (19) adult women at risk for type 2 diabetes | 240 mL of wild blueberry juice containing 314 mg total anthocyanin. | Seven (7) days study. | 1. No effects on some cardiometabolic and inflammatory markers 2. Lowered systolic blood pressure. 3. Increased serum concentrations of nitrates and nitrites. | Stote et al. 2017 |