None listed
Conditions
Brief summary
The primary objective of this research is to investigate how long term KF powder consumption may impact sleep quality and its downstream effects on cognition, mood, stress, metabolites and gut microbiota. KF contain a protein named actinidin, which is a protease enzyme involved in enhancing the digestion of proteins into amino acids. Some of these amino acids are precursors of neurochemicals required for sleep-wake regulation. KF is a known source of folate and vitamin C, which is essential in the metabolism of amino acids into neurochemicals. Consumption of kiwifruit (KF) one hour before bed improves sleep as measured by actigraphy. However, this study does not provide evidence on how sleep quality and biochemical measures may be affected. A randomised, double-blind, controlled, crossover trial is planned. Participants will consume a control or a dried green kiwifruit powder (equivalent to two fresh green KF). An activity monitor on the non-dominant arm will be used for sleep assessment and mood/stress/cognitive tests will be completed. Measures will be conducted on each intervention after 14 days of intervention consumption, and 14 days after washout. Blood and urine will be collected and analysed for metabolites and faecal samples sequenced for microbial populations and metabolites. This study will allow a better understanding of how KF consumption may improve sleep and assist in understanding a possible mechanism.
Interventions
This is a double-blind, placebo-controlled, parallel cross-over design intervention study that will allow us to evaluate whether long-term supplementation with green kiwifruit powder (which includes the skin) on sleep quality and melatonin concentrations. Additionally, we seek to determine impacts on other metabolites, mood, stress, cognition, host-microbial metabolites and gut microbiota.
Prospective participants who have met the study's inclusion/exclusion criteria will be asked to attend a
This is a double-blind, placebo-controlled, parallel cross-over design intervention study that will allow us to evaluate whether long-term supplementation with green kiwifruit powder (which includes the skin) on sleep quality and melatonin concentrations. Additionally, we seek to determine impacts on other metabolites, mood, stress, cognition, host-microbial metabolites and gut microbiota. Prospective participants who have met the study's inclusion/exclusion criteria will be asked to attend a screening session (approximately 30min) where they will meet with the study’s principal investigator. Enrolled participants will be asked to come into the sleep lab on four separate nights, two weeks apart each time. Two days before each visit, the participant will be asked to abstain from foods rich in melatonin and serotonin. On each in-laboratory visit, subjects will be in the laboratory-based assessments at 17:00 hr and complete surveys and questionnaires. Immediately following the first questionnaire, participants will have a venous cannula inserted and a blood sample taken. Blood samples will be collected every hour until bedtime in a room lit to 10lux. At 18:00 hr, a standardised dinner is served and is to be consumed within 30min. Profile of Mood States (POMS) will be completed on arrival 17:00 hr, before bedtime 22:00 hr and waking 07:00 hr. Upon waking, single blood, urine and faecal sample will be collected. Lastly, the participants will complete a cognitive battery at waking; after this, they will be allowed to leave the laboratory. Participants will be required to undergo a two-week washout period (no kiwifruit consumption) before starting the first arm of this study, beginning after their screening session. They will then have an in-lab visit after this washout (Baseline). For the first arm of this study, recruited participants will be evenly randomised into two treatment groups: (1) freeze-dried green kiwifruit powder and (2) Placebo group. At the start of the study arm, the trial coordinator will give participants bottles containing pre-weighed amounts of either the freeze-dried green kiwifruit powder (32g) or the placebo (22g). Participants will be instructed to consume the intervention with 200ml of water once daily for two weeks after their evening meal. They will be asked to add 50ml of water to ensure that they consume as much product as possible. The trial coordinator will check-in with each participant weekly and ask participants to return unconsumed items on day 14 of each dietary intervention period to monitor compliance. A text message reminder will be sent daily to remind the participants to consume the intervention. On day 14 of their supplementation period, participants will be asked to return to the research facility and complete their in-lab sleep quality as previously described. The difference is that after their standardised dinner is served, they will also be given the intervention they are currently allocated to. Like the first prior arm, participants will be required to under two weeks of washout. They will undergo the same dietary restrictions. This can start as early as the day after the first trial arm. Following the washout period, participants will return for the third time (baseline 2) to have similar measures measured as above. They will then be asked to consume the dietary intervention (placebo or kiwifruit powder) they did not receive during the first arm. Furthermore, participants will undergo the same sleep quality measures and biochemical measures as the first trial arm on day 14 of their supplementation period.
Sponsors
Massey University
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
Male
Age
18 Years to 45 Years
Healthy volunteers
No
Inclusion criteria
Healthy males Aged between 18-45 years of age Body mass index (BMI) (18.5-30kg/m2) Physically active but no more than 2 hours per day Poor sleepers, defined as having an ISI (Insomnia Severity Index) score of >8 (Ree, Pollitt, & Harvey, 2006) and the Pittsburgh Sleep Quality Index (PSQI) score >5 (Buysse, Reynolds III, Monk, Berman, & Kupfer, 1988) Glycated haemoglobin (HbA1c) test, value <41mmol/mol (greater than this is considered prediabetes) (Braatvedt et al., 2012)
Exclusion criteria
Use of specific prescribed medication as listed below or recreational drugs use: Diuretics, Oral or inhaled steroids, Cholinergic antispasmodics, Lactulose, Metamucil, Antibiotics, Sedative/hypnotic medication, Laxatives, Antacids, Cholesterol-lowering medications, Proton pump inhibitors (acid reflux treatments), Vitamin/mineral supplements, Heparin, Antidepressants Excessive alcohol intake defined as >20g of pure alcohol (2 drinks)/d on average. (>21 standard drinks a week) Smoke cigarettes History of gastrointestinal surgery or gastrointestinal disorders including inflammatory bowel disease (IBD), ulcerative colitis, coeliac disease, Crohn’s disease Medical conditions (e.g., cardiorespiratory, diabetes mellitus, bleeding disorders) Psychiatric conditions (e.g., Major depressive disorder, Schizophrenia) Antibiotic consumption (1 month before the study and during the study) Significant weight loss during the past six months Being on a controlled diet or dietary weight loss regimen within four weeks before and during the study Vegetarian/vegan Aversion to blood sampling Allergies to dairy products or eggs or fruits Participants will be asked to abstain from alcohol before attending a sleep session at the laboratory and to abstain from caffeinated beverages and vigorous exercise eight hours before their averaged bedtimes Diagnosed with or symptoms of COVID-19
Outcome results
None listed