Acute effects of fresh versus dried Hayward green kiwifruit on sleep quality, mood, and sleep-related urinary metabolites in healthy young men with good and poor sleep quality

Alexander P Kanon; Caroline Giezenaar; Nicole C Roy; Warren C McNabb; Sharon J Henare

doi:10.3389/fnut.2023.1079609

Acute effects of fresh versus dried Hayward green kiwifruit on sleep quality, mood, and sleep-related urinary metabolites in healthy young men with good and poor sleep quality

Front Nutr. 2023 Mar 14:10:1079609. doi: 10.3389/fnut.2023.1079609. eCollection 2023.

Authors

Alexander P Kanon^{1

2

3}, Caroline Giezenaar^{2

4}, Nicole C Roy^{2

5

6}, Warren C McNabb^{2

6}, Sharon J Henare¹

Affiliations

¹ School of Health Sciences, College of Health, Massey University, Palmerston North, New Zealand.
² Riddet Institute, Massey University, Te Ohu Rangahau Kai Facility, Palmerston North, New Zealand.
³ Alpha-Massey Natural Nutraceutical Research Centre, Massey University, Palmerston North, New Zealand.
⁴ Food Experience and Sensory Testing Laboratory, School of Food and Advanced Technology, Massey University, Palmerston North, New Zealand.
⁵ Department of Human Nutrition, University of Otago, Dunedin, New Zealand.
⁶ High-Value Nutrition National Science Challenge, Auckland, New Zealand.

Abstract

Background and aims: Daily kiwifruit (KF) consumption has been associated with improved sleep quality, but underlying physiological mechanisms are unknown. This study examined acute effects of fresh and dried green KF, compared with a water control, on sleep quality, mood, and urinary serotonin and melatonin metabolite concentrations.

Methods: 24 men (age: 29 ± 1 years, body mass index: 24 ± 1 kg/m²) with poor (n = 12) or good (n = 12) sleep quality participated in a randomized, single-blind crossover study. One of three treatments was consumed with a standardized evening meal; (1) the flesh of two fresh green KF, (2) dried green KF powder (including skin; equivalent to dry matter of two fresh KF) mixed with water, or (3) a water control, in their own home. Subjective and objective sleep quality, mood, waking urinary 5-hydroxyindoleacetic acid (5-HIAA), 6-sulfatoxymelatonin (aMT6s), vitamin C and B-vitamin concentrations were determined.

Results: Regardless of sleep quality group, compared to control, morning sleepiness, alertness upon awakening, and vigor were improved (p < 0.05) after dried KF consumption. Compared to control, both fresh and dried KF treatments tended (p < 0.1) toward improved esteem and total mood disturbance. Both KF treatments increased (fresh +1.56 ± 0.4 ng/g, p = 0.001; dried: +1.30 ± 0.4 ng/g, p = 0.004) urinary concentration of the serotonin metabolite 5-HIAA compared to the control (4.32 ± 0.4 ng/g). In poor sleepers, ease of awakening improved by 24% after dried KF consumption (p = 0.005) and tended to improve by 13% after fresh KF intake (p = 0.052) compared to the control. Good sleepers tended toward 9% improved ratings of getting to sleep with fresh KF (p = 0.053) compared to the control. Poor sleepers had lower amounts of some B-vitamins compared to good sleepers (p < 0.05).

Conclusion: Consumption of dried or fresh KF with a standard evening meal, was associated with improved aspects of sleep quality and mood, possibly mediated through changes in serotonin metabolism.

Clinical trial registration: [www.anzctr.org.au], identifier [ACTRN12621000046808]. Graphical Abstract.

Keywords: alertness; kiwifruit; melatonin (6-sulfatoxymelatonin); mood; serotonin; sleep.