Aging is a physiological process that results in changes observable to the naked eye (appearance of a few more wrinkles, hair whitening, change in stature or posture…) but also other changes less observable (increased frailty). Aging-related changes also occur within our digestive tract, but they are not always easy for the human eye to detect. Diet and host genetics are critical determinants of gut microbial composition and function, whose origins go back to the moment of birth.

The mode of delivery and early feeding practices (breastfeeding vs formula) are crucial factors that shape the gut microbiota during early life. Neonates have an intestinal microbiota that is characterized by low diversity, mainly dominated by bifidobacteria, and with a composition profile in terms of species that is unique to each infant. An increase in gut microbiota diversity is later driven by the diversification of the diet: introduction of fruit and vegetables cereal flours and protein-rich foods. At around 3 years of age, the gut microbiota of a child has stabilized and resembles that of an adult.

Drugs such as antibiotics, painkillers and diabetes medication, as well as Westernized dietary regimes, can lead to major perturbations of the gut microbiota, resulting in a different gut microbiota profile with consequences for health that are not always well understood.

After the age of 60, gut microbiota diversity begins to decrease and is characterized by considerable variability between people, resembling the same pattern observed in infancy.

The good news is that lifestyle can outweigh age-related gut microbiota changes. Irish scientists found that where older adults live and their lifestyle in that place is a major determinant of their gut microbiota diversity.

Elderly people living at their homes and cared for by caregivers showed the highest diversity in their gut microbiota, followed by those living in day-hospital and rehabilitation, with older people in long-term care showing the least diverse microbiota. Long-stay subjects in residential care showed the lowest diversity in their gut microbiota and also scored poorly for diverse health parameters.

The relevance of lifestyle for limiting age-related changes in the gut microbiota is also supported by a second study that found that the gut microbiota composition of healthy aged individuals living in rural and urban provinces in China was remarkably similar to that of healthy 30-year-olds from the same population.

There is a link between healthy aging and a healthy gut. In the light of current findings, maintaining the diversity of our gut microbiota as we age through a healthy lifestyle and diet could be considered an indicator of healthy aging, just like keeping active and sleeping well are indicators of wellbeing.

This article is adapted from the post “Gut microbiota from cradle to grave: does age or lifestyle matter more?”, written by Paul Enck and Kristina Campbell for the Science Trends website.

References:

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2. Guaraldi F, Salvatori G. Effect of breast and formula feeding on gut microbiota shaping in newborns. Front Cell Infect Microbiol. 2012; 2:94. doi: 10.3389/fcimb.2012.00094.
3. Rodríguez JM, Murphy K, Stanton C, et al. The composition of the gut microbiota throughout life, with an emphasis on early life. Microb Ecol Health Dis. 2015. doi: 10.3402/mehd.v26.26050.
4. Hollister EB, Riehle K, Luna RA, et al. Structure and function of the healthy pre-adolescent pediatric gut microbiome. Microbiome. 2015; 3:36. doi: 10.1186/s40168-015-0101-x.
5. Bian G, Gloor GB, Gong A, et al. The gut microbiota of healthy aged Chinese is similar to that of the healthy young. mSphere. 2017; 2(5). doi: 10.1128/mSphere.00327-17.
6. Claesson MJ, Jeffery IB, Conde S, et al. Gut microbiota composition correlates with diet and health in the elderly. Nature. 2012; 488(7410):178-84. doi: 10.1038//nature11319.

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