This collection of dried out foods, an orange and apple, the shell of a walnut and a plastic lemon represent the range of different foods we might test. Alternatively, sometimes we might take a food element out of its natural form and present it in capsules, so we can give volunteers a specific dose. The capsules are a form of yeast β-glucan (or spent brewer’s yeast) which may have the ability to train our immune system…. Diet can up- or down- regulate our immune response – hence the term immune training. At present my team is very interested in understanding how we can use diet to up/ down regulate metabolism to impact immune responses.  We’ll let you know how we get on in a few years…….