Current research on disease-microbiome correlations has taken a new focus on healthy microbiome aging. As the human body ages, so does the gut microbiome.
To pinpoint distinct microbes associated with disease, research is learning to understand the stages of healthy microbiome aging and when prevention methods can increase overall health.
Recognising the significance of the gut microbiome in human health, there is a fundamental need to cultivate strategies for the well-controlled development of the childhood gut microbiome and continued healthy gut microbiome ageing.
Disease-microbiome association in children
Children across the world are close to facing epidemic levels of obesity and diabetes, with the African population witnessing the number of overweight children under 5 years increase by almost 24% since 2000.
Research has shown that the gut microbiome and its interaction with immune cells and metabolic organs have a significant role to play in childhood obesity development. More specifically, dysbiosis in the gut microbiome, stimulation of inflammatory cytokines, changes in the metabolic functions of brown adipose tissue and the browning of white adipose tissue have all been associated with increased childhood obesity.
In the reverse correlation, the microbiome has been shown to influence childhood malnutrition, too. The gut microbiome has multiple purposes, such as regulating energy collection from nutrients, signalling growth hormones, resistance to colonisation and immune tolerance against pathogens.
Through undernourished diets, there is a disturbance of the normal gut microbial ecosystem, which may further disturb the essential pathways correlated with healthy child growth.
Disease-microbiome association in adults
A recent study compared the gut microbiomes of over 2 500 individuals (aged 20 – 89). Within this group, there were individuals with inflammatory bowel disease, colorectal cancer, type 2 diabetes, intestinal polyps and liver cirrhosis.
It was found that younger people gradually began developing disease-associated gut microbes, while older individuals tended to lose the ‘healthy’ gut microbes. Even more so, this study identified a set of gut microbes that were gained across many diseases and age-groups.
This particular set of microbes was also found to be related to frailty in elderly people and their characteristics have all been known to have damaging effects on human health.
In another study, unusually enriched populations of Firmicutes and Bacteroidetes were present in gut microbiota of Egyptian diabetic and obese adults, the when compared to the control group. This study concluded that the health state of such adults was recognised by the structure of the gut microbiota.
Disease-microbiome association in the elderly
As already recognised in the centenarian study, long-living, healthy individuals were found to have a more diverse gut microbiota than their younger adult counterparts. Furthermore, this study identified several potentially beneficial bacteria enriched in the long-living group.
This study indicated a general increase in Proteobacteria during aging, which is thought to be a common change in gut microbiome ageing, irrespective of typical elderly or long-living subjects. Furthermore, the relative abundance of Faecalibacterium in the long-living people reduced when compared to the younger group across cohorts.
A recent review observed how proper nutrition positively impacted the prevention of depressive symptoms among elderly individuals. The findings highlighted a substantial correlation between the intakes of vitamin B and a decrease in the prevalence of depressive symptoms. Even more so, sufficient nutrient intake of tryptophan seems to be an essential factor in terms of nutrition and serotonin levels in the body.
Although the above studies’ results are promising, further studies are necessary to determine how the gut microbiome plays critical roles in healthy aging.
The topic requires ongoing efforts to further characterise the functions of the microbiome and the mechanisms underlying host-microbe interactions, as this will provide a better understanding of the role of the microbiome in health and disease.