Jamie Oliver celebrates the ingredients that can help the brain to function, starting by serving up a salmon traybake served with harissa-spiced chickpeas and couscous. He follows this up with chicken balls in a vibrant vegetable broth - a dish that includes B vitamins - and spinach and lentil fritters packed with iron - which helps transport oxygen around the body. Jamie also explores the latest science around how fibre can help the immune system, turning one of the best sources of fibre, beans, into a brunch or lunch using crispy filo pastry, egg and spices.