Water
Seeing as around 80 per cent of the brain is made up of water, it doesn’t take a brain surgeon to see that drinking plenty will keep the brain hydrated so that it can function at optimum levels.Not surprisingly, many schools are heeding this advice and providing their pupils with water bottles to keep them topped up throughout the day so that they remain alert. Try to drink at least 2 liters (67.6oz) of fluid a day.