Influence of Beverage Choice on Hydration Status Cognition and Learning in Children

The main aim of this clinical trial is to compare the beverage hydration index of three different beverages in primary school-aged children.The Beverage Hydration Index (BHI), compares the hydration value of beverages against plain water. This study will explore the fluid retention capabilities of semi-skimmed milk, milk permeate, and water. This study will also investigate: * Identify the most effective beverage for hydration and the potential cognitive and mood benefits. * To test if these beverages have any effect on gastric emptying * To test if these beverages have any effect on appetite. * To test the acceptability and palpability of semi-skimmed milk, milk permeate, and water in primary school-aged children. Participants will: * Take part in three study days (one for each beverage) * Study day will take part between 9:00AM-12:30PM * Participants will also record their food and fluid consumption the day before and consume a standardised breakfast before each trial. * The beverage hydration index will be calculated as the mass of urine collected following control (water) consumption divided by the mass of urine collected following treatment. * Blood and urine samples will be taken to measure hydration * Breath samples will be taken for gastric emptying rate * COMPASS (Computerised Mental Performance Assessment System), fNIRS (Functional Near Infrared Spectroscopy) and visual analogue scales (VAS) measures will be obtained to assess cognition/mood * An ad libitum pasta meal will be consumed after the trial to measure appetite, along with blood glucose and GLP-1 and further VAS to measure self reported hunger and fullness. * A focus group will be held following completion of all three beverage trials, to gather participants opinion of each drink.