Table 3.

Health benefits of blackcurrants based on human studies.

Health Benefit	Model Used	Results	Reference
Treat neurological conditions such as PD	Plasma and CSF collected from 11 male patients before and after 300 mg of BCA was taken twice daily for 4 weeks	Significant increase in cGP with an increase in BCA dose (p < 0.01). Strong correlation between the concentration of cGP in CSF and plasma (p = 0.01).	[29]
Neuroendocrinological and Cognitive benefits	In a randomized, double-blind, placebo-controlled, cross over study, 36 healthy adults from Auckland NZ aged 18 to 35 were given either 0 mg of PP (Control) or 525 ± 5 mg of polyphenols per 60 kg of bodyweight from ANC-enriched BC extract or 142 mL of BC fruit juice	Significant inhibition of MAO-A and MAO-B. Amount of processing and BC cultivar is a major factor in neuroendocrinological and cognitive benefits.	[32]
Treat neurological conditions	In a double-blind, placebo-controlled, randomized cross- over study, 8 healthy male aged 20–35 consumed NZ Blackadder juice. Measurements were obtained at baseline 15, 30, 45, 60, 100, 120, 150, 180, 240 min, and 24 h post dose	A fast, absolute, and reversible inhibition of blood platelet MAO-B (p < 0.001). Significant but delayed reduction in plasma prolactin (p < 0.001) following the consumption of BC juice.	[33]
Positive affective responses during a self-motivated exercise	In a parallel, randomized controlled study, 40 healthy sedentary male and female participants drank a BC juice (4.8 mg/kg bodyweight) or PLA. After 3- or 5-min intervals on a treadmill, heart rate and exertion (ES) or feeling/mood scores (FS) were measured. Markers were measured pre- and postexercise	A 90% decline in platelet MAO-B activity. ES increased in both groups; however, ES for the BC group were lower than the PLA group (p < 0.05). FS was inversely related to ES only for the PLA group (r2 = 0.99, p = 0.001).	[34]
Mood and Attention	In a randomized, double-blind and placebo-controlled crossover design, 9 healthy adults consumed either BC juice (500 mg polyphenols/drink) or PLA. Neuronal activity was determined related to cognitive performance using EEG.	Reduced anxiety, greater alertness, lower fatigue and small increase in reaction times was seen after the consumption of a single serve BC juice.	[35]
Exercise Recovery	Healthy adults (32) who exercised daily, rowed for 30 min prior to consumption of BC extract (PLA, 0.8, 1.6, or 3.2, mg/kg total ANC). Blood samples were taken throughout	Post-exercise HR was significantly (p < 0.05) lower in participants who had consumed 0.8 or 1.6 mg/kg BAE compared to the PLA. Consumption of 1.6 or 3.2 mg/kg BAE showed elevated pre-exercise plasma oxidative capability and lowered post-exercise plasma carbonyl levels compared to PLA. Neutrophil phagocytic capability was preserved after consumption of BAE before exercise	[36]
Exercise recovery	In 2 double-blind placebo-controlled trials, 18 healthy adults with moderate daily physical activity, consumed BAE (3.2 mg/kg ANC) or PLA 1 h prior to 30 min of rowing exercise for 5 weeks	Significant reduction in lipid oxidation product MDA (p < 0.05). BAE promotes beneficial, protective antioxidant/anti-inflammatory cellular events.	[37]
Improve cardiovascular function	Fifteen endurance male cyclists were randomly assigned to consume different amounts of BCE for 7 days with a 14-day washout (300, 600, or 900 mg/day). Results for cardiovascular function during supine rest were collected.	Cardiac output and stroke volume increased, and peripheral resistance decreased compared to the control.	[38]
Improved Athletic Performance and Recovery	In a double blind, placebo controlled, randomized design, 13 triathletes with >3 years of experience consumed 6 g of BC powder for 7 days and physiological and cardiovascular responses were obtained.	After intake of BC cycling intensity was 6% higher, and there was no effect on heart rate and oxygen uptake. When resting, stroke volume (25%) and cardiac output increased (26%). Total peripheral resistance decreased (16%) and blood pressure and heart rate were not affected.	[39]
Improved Athletic Performance	In a double blind, randomized, crossover design, 14 healthy men consumed BCE (300 mg/day with 105 mg of ANC) or a placebo. After 30 min of cycling and a 16.1 km time-trial, results were collected.	With BCE consumption, fat oxidation increased by 27% and the 16.1 km performance was improved (2.4%). Plasma lactate was higher after the 16.1 km time-trial when BCE was consumed.	[40]
Improved Athletic Performance and Recovery	In a double-blind, randomized, crossover design, 13 active males consumed BCE (300 mg/day with 105 mg of ANC) or a placebo for 7 days and completed a series of sprints at different speeds with 15 s of low intensity running and 1 min of rest between sprints.	BCE consumption increased total running distance by 10.6% compared to the placebo. Blood lactate was higher at exhaustion for those who consumed BCE. Greater lactate change after 15 min of recovery.	[41]
Improved Athletic Performance	In a double-blind, randomized, crossover design, 18 male climbers consumed BCE supplementation (600 mg/day with 210 mg ANC) or placebo for 7 days. Climbing performance was assessed after 3 climbs.	Pull-up performance was not affected Heart rate and total climbing time increased compared to the placebo Fatigue was present regardless of supplementation or not	[42]
Diabetes	In a randomized, double-blind, crossover trial, 14 men and 9 post-menopausal women consumed a BC extract drink with 150, 300, or 600 mg of total ANC before a high-carbohydrate meal or the PLA. Plasma glucose, insulin, GIP, GLP-1, Plasma 8-isoprostane F2α, and arterial stiffness was measured at 0 and 120 min.	Plasma glucose, plasma insulin, plasma GIP, and plasma GLP-1 concentrations were significantly reduced compared to the control.	[44]
Reduce acute endothelial dysfunction caused by smoking	In a randomized, double-blind trial on young, healthy male smokers (13) and nonsmokers (11), the effects of FMD and skin temperature were tested after no supplement, 50 mg BCA, or 50 mg BCA plus Vit E.	After consumption of 50 mg BCA, FMD decreased 1h after smoking and restored to the baseline level 2h after smoking. The skin temperature decreased in the smoker group after smoking compared with that in the nonsmoker group, whereas after BCA supplements, it was higher in the smoker group compared to nonsmoker group.	[45]
Reduce arterial stiffness and blood pressure	In a randomized, double-blind, placebo-controlled, crossover design study, fourteen older adults aged 73.3 ± 1.7 years took either a 7-day course of placebo or two capsules of NZBC extract (each 300 mg capsule contains 35% BC extract) followed by a washout period of 28 days and then switched trials after. Carotid-femoral pulse-wave velocity and central blood pressure were measured.	Carotid-femoral pulse-wave velocity and central blood pressure decreased from both the baseline and placebo. No effects were observed on serum lipids.	[47]

ANC—anthocyanin, BAE—blackcurrants anthocyanin-rich extract, BC—Blackcurrants, BCA—Blackcurrants anthocyanin, cGP—cyclic glycine-proline, CSF—cerebrospinal fluid, EEG—electroencephalography, FMD—flow-mediated dilatation, GIP—glucose-dependent insulinotropic polypeptide, GLP-1—glucagon-like peptide, MAO—monoamine oxidase, MDA—malondialdehyde, NZ—New Zealand, PLA—placebo, PP—polyphenol.