Timed consumption of a New Zealand blackcurrant juice support positive affective responses during a self-motivated moderate walking exercise in healthy sedentary adults

Abstract

Background

Affective responses experienced during exercise are a significant determinant on exercise adherence. We have previously demonstrated that consumption of New Zealand (NZ) blackcurrants preserves cognition by attenuating the feeling of fatigue. This positive affective response correlated with the ability of blackcurrant polyphenols to support monoamine neurotransmission via inhibition of monoamine oxidase-B (MAO-B) activity. Here we explore how the consumption of a NZ blackcurrant juice (BJ) influenced affective responses and potential ergogenic action on the motivation to adhere to a low impact walking exercise.

Methods

In a parallel randomized controlled study (Trial registration #: ACTRN12617000319370p, registered 28th February 2017, http://www.anzctr.org.au/), 40 healthy sedentary male and female participants drank a BJ or matched placebo (PLA) (n = 20 per group), 1 h prior to a self-motivated treadmill walk, where heart rate and affective responses (exertion [ES] or feeling / mood [FS]) scores) were recorded at 3 or 5 min intervals. Blood glucose, lactate, malondialdehyde (MDA) and platelet MAO-B activity were measured pre- and post-exercise and comparisons were conducted using with Student’s t-tests. Subjective data were analysed using 2-way ANOVA with appropriate post hoc tests.

Results

Consuming a BJ 1 h prior to exercise caused a 90% decline in platelet MAO-B activity. The exercise had no significant (p > 0.05) effect on blood lactate, glucose or plasma MDA levels. Assessment of affective responses over the first 60 mins (adjusting for participant drop-out) revealed a time-dependent ES increase in both groups, with ES reported by participants in the BJ group consistently lower than those in the PLA group (p < 0.05). FS declined in PLA and BJ groups over 60 mins, but an inverse relationship with ES was only observed within the PLA group (r² = 0.99, p = 0.001). Whilst the average time walked by participants in the BJ group was 11 mins longer than the PLA group (p = 0.3), and 30% of the BJ group achieving > 10 km compared to only 10% for the PLA group (p = 0.28), statistical significance was not achieved.

Conclusion

Our findings demonstrate that drinking a polyphenolic-rich NZ blackcurrant juice 1 h prior to exercise supports positive affective responses during a self-motivated exercise.

Keywords:

• Self-motivated exercise
• Timed efficacy
• Blackcurrant polyphenols
• Affective response
• Monoamine oxidase-B activity

Dominic Lomiwes, Nayer Ngametua, Natalie S. Burr, Janine M. Cooney, Greg Sawyer, Duncan Hedderley, Suzanne M. Hurst. These authors provided significant contribution to this work.

Dominic Lomiwes, Nayer Ngametua, Natalie S. Burr, Janine M. Cooney, Greg Sawyer, Duncan Hedderley, Suzanne M. Hurst. These authors provided significant contribution to this work.

Acknowledgments

The authors thank the individuals within The New Zealand Institute for Plant & Food Research Ltd. and the wider Palmerston North community who kindly agreed to be participants in the trial. We also thank The New Zealand Blackcurrant Co-operative Ltd. for providing the blackcurrant juice (BJ) concentrate used in this study. The authors would also like to thank Ms. Dawn Harvey for her food safety evaluation and expertise as well as Dr. Lee Huffman and the Food Solutions team of The New Zealand Institute for Plant & Food Research Ltd. for overseeing the food safe packaging of both the BJ and placebo drinks. The authors also thank Drs. Andrew Carroll and Edward Walker for their constructive guidance during the construction of the manuscript.

Authors’ contributions

DL conceived the idea, design and execution of the study, obtained human ethical approval and was the primary person responsible for data collection, interpretation of results and assisted in the writing of the manuscript. BH contributed to the development of the study idea and design. NN was the trial coordinator and oversaw participant recruitment and compliance. NSB performed experimental analysis on collected blood samples. GS performed experimental analysis on collected blood samples. TMT prepared and performed HPLC analysis on the blackcurrant juice concentrate. JMC analysed and interpreted the HPLC blackcurrant juice concentrate data. DH advised and performed statistical analysis on data as well as contributed to the interpretation of results. RDH assisted in securing internal funding, design of the study and writing of the manuscript. SMH conceived the idea and design (with DL & BH) for the study, secured internal funding, obtained human ethical approval (with DL), interpretation of results and main writing of the manuscript. All authors read and approved the final manuscript.

Funding

Financial support for this study was provided by The New Zealand Institute for Plant & Food Research Ltd., who had no influence on the study design, data collection, data analysis, data interpretation, nor the writing of this manuscript.

Availability of data and materials

The data sets for this manuscript are not publicly available because of commercial sensitivity. Requests to access the datasets should be directed to the corresponding author.

Ethics approval and consent to participate

This study was carried out within The New Zealand Institute for Plant & Food Research Limited and was approved by the Northern A Health and Disability Ethics Committee of New Zealand (Auckland); 17/NTA/9 and registered with Australian New Zealand Clinical trial register (#ACTRN12617000319370p). All subjects gave written informed consent in accordance with the Declaration of Helsinki.

Consent for publication

No personalized data was used in the preparation of this manuscript.

Competing interests

There are no competing interests. The BJ used in this study was provided in kind by The New Zealand Blackcurrant Co-operative Ltd. who had no influence on the study design, data collection, data analysis, data interpretation, nor the writing of this manuscript.

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