Diet, the gut microbiota and healthy ageing: How dietary modulation of the gut microbiota could transform the health of older populations
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.
THE HUMAN GUT MICRIOBIOTA: ITS ROLE AND ITS POTENTIAL
The total collection of microbes that naturally exist in the gut of an individual (the microbiota) contains trillions of bacteria – approximately tenfold more than the 1014 human cells in the body (1). The microbiota is unique, remarkably diverse and stable over defined periods of time (1, 2), with older adults displaying greater inter-individual variation than that of younger adults (2). The human gut microbiota has a close symbiotic relationship with its host and conveys essential benefits; it extracts energy from the diet, produces nutrients, regulates the stress response, protects against attack by other organisms and both primes and modulates the immune system (3, 4). In addition, the collective genetic information of the gut microbiota (the microbiome), contains over 100 times the number of genes in the human genome and provides increased physiological abilities (5).
The availability of improved, and constantly improving, culture-independent, sequencing and bioinformatics technologies to interrogate the complexity of the microbiota has driven efforts to understand its role in promotin ...