Acute supplementation with blackcurrant extracts modulates cognitive functioning and inhibits monoamine oxidase-B in healthy young adults

Abstract

Newcastle University ePrints -eprint.ncl.ac.uk Watson AW, Haskell-Ramsay CF, Kennedy DO, Cooney JM, Trower T, Scheepens A. Acute supplementation with blackcurrant extracts modulates cognitive functioning and inhibits monoamine oxidase-B in healthy young adults. Abstract 42Background: Berry fruit have been shown to convey a number of benefits in animal models; 43including improvements in cognitive performance, slowing of cognitive decline and 44 neuroprotection. These findings, along with epidemiological evidence and data showing 45 modulation of factors related to brain function, suggest a potential role for berry 46 polyphenols in improving cognitive performance. 47Objective: The current study assessed the effects of two blackcurrant extracts on cognitive 48 outcomes, mood, blood glucose profile and peripheral monoamine levels. Anthocyanin 49 bioavailability was also assessed. 50 Design: A randomised, double-blind, placebo-controlled, crossover study was conducted in 51 36 healthy young participants (18-35y). Following a 10 minute baseline assessment, 52 participants consumed sugar, flavour and colour matched drinks containing no polyphenols 53 (control) or 525 +/-5mg of polyphenols per 60kg body weight from either an anthocyanin 54 enriched powdered blackcurrant extract (Delcyan TM ) or cold pressed blackcurrant juice 55 (cultivar Blackadder) in counterbalanced order on separate days. A 70-minute computerised 56cognitive assessment (COMPASS) designed to be attentionally demanding and mentally 57fatiguing was then completed following a 60-minute resting absorption period. Blood 58 platelet monoamine oxidase-B (MAO-B), plasma anthocyanin levels, plasma prolactin and 59 plasma monoamines and associated metabolites were also investigated in a subsection of 60 the cohort at 2.5 hours post-consumption. 61Results: When compared to control, both blackcurrant extracts improved attention task 62performance. The juiced extract reduced reaction times during the digit vigilance task, 63whereas the powdered extract increased accuracy during a rapid visual information 64 processing task. Following the juiced Blackadder extract, platelet MAO-B was inhibited by 65 96%, dihydroxyphenylglycol (DHPG) was reduced and normetadrenalin was increased in 66 blood plasma, and a rapid decline in blood glucose levels was significantly attenuated, when 67 compared to control. 68Conclusion: This is the first illustration of a cognitive benefit of acute blackcurrant 69 supplementation in healthy young humans and the first description of a clinically significant 70 inhibition of MAO-B and MAO-A using a commonly consumed fruit. These data also illustrate 71 that compounds other than anthocyanins are important to observe in vivo MAO inhibition 72and that the degree of processing and cultivar of blackcurrant fruit used substantially alters 73 the neuroendocrinological and cognitive benefits conveyed. 74 75

Anthocyanin-rich plum juice reduces ambulatory blood pressure but not acute cognitive function in younger and older adults: a pilot crossover dose-timing study

“…A crossover study [19] found that high anthocyanin cherry juice consumption did not result in any significant acute effects on a battery of cognitive tests in either younger or older adults. Contrary to this, Watson et.al, (2015) [20] observed a cognitive benefit of acute blackcurrant supplementation in healthy younger adults possibly explained by an association between monoamine oxidase (MAO) inhibition and improved attention. There is a possibility that the inhibition of MAO have positive effects on monoaminergic neurotransmission during cognitive performance [21].…”

“…The precise mechanism by which anthocyanins affect cognition is still not clear but seems to be dependent on the exposure period. Acute effects on cognition are believed to be as a result of increased cerebrovascular blood flow and possibly monoamine oxidase (MAO) inhibition which has been shown to improve cognitive performance [14,20]. Following consumption of high anthocyanin fruit/juice, evidence shows that peaks in cerebral blood flow, vasodilation, and anthocyanin metabolite availability is detectable within 2h post consumption [17].…”

Food‐based anthocyanin intake and cognitive outcomes in human intervention trials: a systematic review

“…Watson et al . compared three conditions (placebo versus powdered blackcurrant extract with 7.7 mg anthocyanins kg −1 versus blackcurrant juice with 8 mg kg −1 , based on body weight) on acute cognition in 36 young adults by administering tasks seven consecutive times over 65 min after consumption of the beverages. Significant improvements in accuracy were reported, as measured by the rapid visual information processing test ( P = 0.011), when participants consumed the blackcurrant extract versus placebo, as well as improvements in reaction time for some repetitions (1, 4 and 7) on the digital vigilance task compared to baseline tests ( P = 0.044) for blackcurrant juice or extract versus placebo.…”

“…Statistical pooling of the data from the seven studies considered eligible for the review (39)(40)(41)(42)(43)(44)(45) was not possible because of the large clinical and methodological diversity of the studies. This heterogeneity resulted from variability in the characteristics of the participants and type of intervention (including food sources and dose of anthocyanins), varying study designs and study duration, as well as differences in choice of cognitive outcomes.…”

Enhancing attention in neurodegenerative diseases: current therapies and future directions

“…Clinical trials have demonstrated improved attention following flavanol ingestion compared to placebo in a dose-related fashion [94, 95]. A double-blind, controlled, cross-over trial using blackcurrant extracts demonstrated improvement on alerting and orienting but not executive tasks of attention [96]. This finding, however, has not been consistently reproduced with different flavonoid-rich foods [97].…”