Prebiotics and Immune Function in Middle Aged Humans

Prebiotics are naturally occurring carbohydrates found in a variety of edible plants. They are not digested by mammalian enzymes, and so reach the gut intact, where they are fermented by some species of intestinal bacteria. This fermentation is thought to have several benefits for the host including improving immune function. There are numerous methods available for assessing the human immune response. Response to vaccination is thought to be a good method for this. Not many studies have examined the effect of prebiotics on the human immune response to vaccination. Thus the investigators propose to test the effect of a prebiotic on the immune response in healthy volunteers including their response to the current flu vaccine. The investigators hypothesise that the prebiotic will enhance the immune response including the response to the vaccine.