The Effects of Resveratrol Supplementation on Cognition, Cerebral Blood Flow, Microbiota and Systemic Inflammation.

Overview

Previous research shows that a diet high in fat has harmful effects on gut health. This increases the chance of developing obesity-related diseases (such as type 2 diabetes) and disrupts cognition and mood. Research has suggested that gut health can be improved by taking certain supplements, including resveratrol (a polyphenol found primarily in red grape skins). Resveratrol has also been shown to improve brain blood flow and possibly brain function - however, there is limited research studying this. This study will investigate the effects of 12 weeks daily consumption of resveratrol on cognitive function, cerebral blood flow, gut microbiota and systemic inflammation in overweight and obese healthy adults.

Each participant will be required to attend the laboratory on four occasions. The first of these will be an initial screening/training visit, this will take place in the afternoon and last 3 hours in total. During the initial visit participants will be asked to provide written informed consent. They will provide lifestyle and demographic data and screened regards to physical health (height, weight, blood pressure, waist to hip ratio). They will then be trained on the computerised cognitive and mood tasks. At the end of the appointment they will be provided with a food diary and a stool sample collection kit. Study days 1 and 2 (12 weeks apart) : Participants will arrive at the laboratory at 8.00am having fasted from 8pm the previous evening, avoided caffeinated products for 18 hours, alcohol and over the counter medication for 24 hours and oral antihistamines for 48 hours prior to the session commencing. They will also bring with them their completed food diary and stool sample. Participants will provide a blood sample and then will be given a standardised breakfast of x2 slices of white toast with butter and a decaf tea or coffee. They will also provide a urine sample. Participants will then complete a computerised cognitive assessment (\~1 hour in length), followed by measurements of blood pressure and heart rate. Participants in the sub-sample who will also provide brain (cerebral) blood flow data, will then have the quantitative near-infrared spectroscopy (qNIRS) headband fitted across the forehead and a 5 minute baseline measure will be recorded. Following this the participants will consume their treatment for the day, followed by a short break and then will complete the second cognitive assessment. The qNIRS participants will again provide brain blood flow data and following that will be provided with a standardised lunch (cheese sandwich, ready salted crisps and a custard pot). Participants will complete their final cognitive assessment and will then provide a second blood sample. At the end of the first study day participants will be provided with their treatment and treatment diary, they will be instructed to take one tablet twice a day (with breakfast and dinner). Both study days will be identical and will take place 84 days (+/- 5 days) apart. Participants are also required to attend a short treatment exchange visit during Week 6 (5 minutes).