Insights & Discussion
Consumption of fresh or dried kiwifruit in the evening improves aspects of sleep quality and mood, potentially mediated through changes in serotonin metabolism.
A randomized, single-blind crossover study involving 24 men with varying sleep quality levels was conducted. Participants were provided with one of three treatments during their standard evening meal at home: the flesh of two fresh green kiwifruits, dried green kiwifruit powder (with skin and equivalent to the dry matter of two fresh kiwifruits) mixed with water, or a water control. Various factors were evaluated including subjective and objective sleep quality, mood, and urine concentration of several compounds including the serotonin metabolite 5-HIAA, vitamin C, and B-vitamins.
Findings indicated that regardless of sleep quality group, dried kiwifruit consumption was associated with an improvement in morning sleepiness, alertness upon waking, and vigor as compared to the control. Both fresh and dried kiwifruit treatments suggested an improvement in self-esteem and overall mood disturbance. Increase in the urinary concentration of serotonin metabolite was observed with both kiwifruit treatments. Amongst poor sleepers, ease of awakening was notably improved after the intake of dried kiwifruit and showed signs of improvement with fresh kiwifruit. For good sleepers, there seemed to be an improvement in getting to sleep with fresh kiwifruit. Poor sleepers were found to have lower quantities of certain B-vitamins compared to good sleepers. Thus, both dried and fresh kiwifruit consumption with a standard evening meal showed a positive impact on sleep quality and mood.
Discover Related Insights
Consuming two medium-sized green kiwifruits an hour before bed can improve sleep quality and recovery stress balance among elite athletes.
2023 Nutrients The Impact of Kiwifruit Consumption on the Sleep and Recovery of Elite Athletes Doherty R, Madigan S, Nevill A, Warrington G, Ellis JG
Clinical Study Exercise Performance Kiwifruit Sleep
The study began with an initial assessment, after which all participants were instructed to consume two medium-sized green kiwifruits an hour before bedtime over a 4-week span. Data was collected through baseline and post-intervention questionnaires, as well as daily sleep diary entries throughout the study duration.
There was a notable positive effect of kiwifruit consumption on essential aspects of sleep and recovery in professional athletes. After the intervention period, improvements were observed in sleep quality and recovery stress balances. Additionally, there was an increase in total sleep time, sleep efficiency, and a decrease in the number of times participants woke after falling asleep. The study concludes that kiwifruits positively influence sleep and recovery in high-performing athletes.
The ethanol extract from green kiwifruit peel enhances sleep duration and onset, proving to be a potential natural aid for treating sleep disorders.
2022 Nutrients Effects of Green Kiwifruit Peel Extract on Sleep-Wake Profiles in Mice: A Polysomnographic Study Based on Electroencephalogram and Electromyogram Recordings Kim D, Yoon M, Kim S, Um MY, Cho S
Experimental Study Kiwifruit Sleep
The study employed the electroencephalogram (EEG) and electromyogram analysis methodologies in mice to investigate the sleep-promoting effects of the kiwifruit peel extract. Each participant mouse was administered with varying doses (250, 500, and 1000 mg/kg) of green kiwifruit peel ethanol extract (GKPEE) and their sleep duration, latency and onset were consistently observed and recorded. For comparison purposes, results were weighed against similar analyses conducted using diazepam, a traditional sedative-hypnotic drug.
In terms of results, the findings indicated that acute administration of GKPEE significantly increased non-rapid eye movement sleep and decreased sleep latency, in a dose-dependent relationship. Moreover, the effects did not alter delta activity, differing significantly from diazepam outcomes. Notably, these effects prevailed even with sub-chronic administration over 15 days, with the EEG power density not revealing any noteworthy differences - an indicator of the absence of a tolerance phenomenon. Additionally, these results suggest an alternative usage of kiwifruit by-products from the food industry, providing possible environmental benefits.
Consuming New Zealand green kiwifruit improves sleep quality, mood, and increases the concentration of serotonin metabolites.
2022 NSNZ 2021 Acute Evening Consumption of Green Kiwifruit in Young Men Enhances Waking Alertness, Mood and Increases 5-Hydroxyindoleacetic Acid in Urine Kanon AP, Giezenaar C, Roy NC, McNabb WC, Henare SJ
Randomised Controlled Trial Kiwifruit Mood Serotonin
A total of 24 men, ranging in age and with varying sleep quality were selected for the study, in a single-blind crossover design, which was randomized. Participants were provided three treatments on separate occasions, each differing by 6-8 days: consumption of two fresh kiwifruits, ingesting green kiwifruit powder mixed with water equivalent to two fresh kiwifruits, or a simple water control.
Poor sleepers noted that they woke up more easily after consuming dried kiwifruit, with a similar but less pronounced trend observed when they consumed fresh kiwifruit. Conversely, good sleepers showed a trend towards better sleep initiation with fresh kiwifruit, but not with the dried kiwifruit. Independent of the participants' sleep quality, both fresh and dried kiwifruit largely improved mood and self-esteem. Consumption of dried kiwifruit significantly elevated morning alertness, post-wakening behaviour, and vigour. Both forms of kiwifruit ingestion led to higher urinary concentrations of the serotonin metabolite known as 5-HIAA.
Kiwifruit consumption before bedtime significantly improves sleep quality and daytime function in individuals with chronic insomnia in comparison to pear consumption.
2017 Sleep and Biological Rhythms The effects of kiwi fruit consumption in students with chronic insomnia symptoms: a randomized controlled trial Nødtvedt O, Hansen AL, Bjorvatn B, Pallesen S
Randomised Controlled Trial Insomnia Kiwifruit Sleep
In the methodology of this study, participants with chronic insomnia symptoms were randomly assigned to consume either 130g of kiwi or pear an hour prior to bedtime daily for a period of 4 weeks. This followed a baseline assessment period of one week. Various outcome measures such as sleep diaries, actigraphy, and several questionnaires were used to evaluate the effects of this dietary change.
The results showed a distinct improvement in sleep quality and daytime functionality in participants who consumed kiwi, as reported in the sleep diaries. However, the objective measures such as actigraphy and certain questionnaires did not show any significant changes. Hence, the research indicates that kiwi might have properties that enhance sleep, especially in people dealing with chronic insomnia.