The human intestinal microbiota has defined health-promoting properties. Alterations in the composition of the microbiota have been linked to common health problems, particularly at dynamic life stages such as older age. Environmental conditions, including diet, shape the composition of the intestinal microbiota. Recent studies have begun to link dietary intake with distinct microbiota compositional profiles and to link these profiles with health parameters in older populations. Defining the role of diet in supporting health-promoting microbiota profiles provides the foundation for the development of dietary interventions specifically targeted at sustaining health in older age.