This study is designed to test the effects of prebiotics on cognition, behavior and physiology in healthy volunteers.
The purpose of this study is to determine the effects of dietary carbohydrate supplements (prebiotics) on cognition, behavior and physiology in healthy individuals. This study will be separated into one pre-study visit + three consecutive weeks: Baseline (week 1), Intervention (week 2) and Assessment (week 3). For these three weeks, participants will be asked to take diet surveys and make in-person visits to complete online cognitive assessments and provide samples of blood and saliva to assess levels of serotonin and cortisol in addition to other basic metabolites. During the Intervention week, participants will be given snack bars that they will be asked to eat twice a day, for five days in a row. There will be two treatment groups that participants will be randomly assigned to, which vary according to the carbohydrate makeup of snack bars. For the entire three-week study period, participants will also be asked to collect samples of their stool at home every Tuesday and Friday. They will also be provided with wearable devices (a watch) to track their daily heart rate and activity level (including sleep) for the entirety of the study. Participants will be compensated for their time for each stage of the study, once in-person visits begin. The greatest risks of this study include the possibility of infection while sampling your own stool, and momentary discomfort and/or bruising associated with blood draws. Discomfort as a result of consuming the bars is possible in the form of flatulence, bloating, constipation, diarrhea, or borborygmi (stomach rumbling). Participants weighing less than 140 pounds may be more likely to develop diarrhea than those weighing more. Should any such discomfort occur, it can be alleviated simply by discontinuing consumption of the prebiotic. Infection, fainting, and excess bleeding/clotting, though highly unlikely, are also possible. Participants also face risks associated with the loss of confidentiality.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
41
9 grams of food grade inulin added to custom made fiber bars.
9 grams of food grade maltodextrin - replaces inulin in fiber bars.
Duke University
Durham, North Carolina, United States
Change in cognitive test performance from baseline
We will measure performance on a ten-domain cognitive battery (score out of 1000 for each domain) and compare the change from baseline between treatment and control groups.
Time frame: Baseline (Day 2, Day 5), Intervention (Day 9, Day 12), and Post-Intervention (Day 16, Day 19)
Change in stool microbiota profile from baseline
Stool samples will be analyzed to determine microbiota composition by 16S rRNA sequencing, and we will compare the change from baseline between treatment and control groups.
Time frame: Baseline (Day 2, Day 5), Intervention (Day 9, Day 12), and Post-Intervention (Day 16, Day 19)
Change in nighttime salivary cortisol from baseline
Saliva samples will be analyzed for cortisol concentration, and we will compare the change from baseline between treatment and control groups.
Time frame: Baseline (Day 1, Day 4), Intervention (Day 8, Day 11), and Post-Intervention (Day 15, Day 18)
Change in blood metabolites from baseline
Blood samples will be analyzed for a panel of metabolites that may be influenced by the intestinal microbiota, and we will compare the change from baseline between treatment and control groups
Time frame: Baseline (Day 2, Day 5), Intervention (Day 9, Day 12), and Post-Intervention (Day 16, Day 19)
Change in sleep quality from baseline
Smart watches will be used to monitor time asleep each night and we will compare the change in this variable from baseline between treatment and control groups
Time frame: Baseline (Days 1-5), Intervention (Days 8-12), and Post-Intervention (Days 15-19)
Change in sleep quality from baseline
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Smart watches will be used to monitor percent of time spent in deep sleepwe will compare the change in this variable from baseline between treatment and control groups
Time frame: Baseline (Days 1-5), Intervention (Days 8-12), and Post-Intervention (Days 15-19)
Change in heart rate from baseline
Baseline (Days 1-5), Intervention (Days 8-12), and Post-Intervention (Days 15-19)
Time frame: Smart watches will be used to continuously monitor heart rate, and we will compare the change from baseline between treatment and control groups
Change in stool short-chain fatty acid (SCFA) content from baseline
Stool samples will be analyzed to determine initial concentrations of SCFAs and capacity to produce SCFAs in response to a prebiotic intervention in vitro, and we will compare the change from baseline in these variables between treatment and control groups
Time frame: Baseline (Day 2, Day 5), Intervention (Day 9, Day 12), and Post-Intervention (Day 16, Day 19)