Measuring Effects of Prebiotics on Human Behavior and Cognition

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.

Eligibility Criteria:
Inclusion Criteria:

* Between age 18 and 35
* Able to provide stool samples at no risk to yourself
* Weigh at least 110 pounds
* Physically able to perform a cognitive examination administered on a laptop with a trackpad (no significant language, hearing, visual or sensory-motor problems)

Exclusion Criteria:

* History or current diagnosis of acute or active major psychiatric disorder (major depressive disorder, generalized anxiety disorder, post-traumatic stress disorder, schizophrenia, bipolar disorder, alcohol or drug dependence, etc)
* History or current diagnosis of any neurological disorder (convulsion or seizure disorder, epilepsy, Huntington's Disease, Multiple Sclerosis, ALS, Parkinson's, dementia, stroke, etc)
* Use of steroid medications, including but not limited to steroid inhalers or creams or lotions that contain steroids, such as hydrocortisone
* Drink greater than 2 alcoholic beverages per day on average
* Recreational drug use, including but not limited to marijuana, cocaine, ecstasy, etc, within the past month
* Known food allergies to soy products
* Dietary restrictions/allergies of milk or dairy products including food products that do not contain nuts, peanuts, eggs, or shellfish, but was manufactured in the same space as these food allergens
* History or current diagnosis of autism or pervasive development disorder
* History or current diagnosis of any learning disability
* History of fainting during blood draws
* Use chewing tobacco
* Currently pregnant
* Currently breastfeeding
* BMI higher than 27.5 or less than 17
* History or current diagnosis of irritable bowel syndrome
* History or current diagnosis of inflammatory bowel disease
* History or current diagnosis of type 2 diabetes
* History or current diagnosis of chronic kidney disease with decreased kidney function
* History or current diagnosis of intestinal obstruction
* History or current diagnosis of untreated colorectal cancer
* Colonoscopy within the past month
* Oral antibiotics within the past month