Modifying the gut microbiome through diet: effects on the immune system of elderly subjects

The human gut microbiome is highly variable among individuals, and is known to be influenced by numerous environmental and host factors. The gut microbiome is modified by diet and shows changes with ageing. The gut microbiome is believed to interact with the host’s immune system. Thus, there is interest in whether dietary probiotics, prebiotics and synbiotics might benefit immune function in older adults, acting through modified gut microbiota to prevent or slow the changes associated with immunosenescence. Here the available evidence from human studies of probiotics, prebiotics and synbiotics and immune function in older adults is reviewed. There is good evidence that probiotics can improve in vivo and ex vivo measures of immune function in older adults. Further research is required before conclusions can be made regarding the role that prebiotics or synbiotics may have on immune function in the elderly. Future studies will need to ensure that the gut microbiome and immune markers relevant to immunosenescence are fully evaluated in robust study designs in order to have greater confidence in the application of these interventions, ensuring that the potential translational value of research in this field is realised