Share on Pinterest What does the gut microbiome have to say about our aging? Image courtesy of Westend61/Getty Images. Measurements of metabolic health can be used to assess the risk of developing cardiovascular disease. Chinese researchers have also shown that metabolic health is characterized by the presence and abundance of certain microbes in the gut microbiome. Age was also associated with certain characteristics of the microbiome, and people with microbiomes associated with younger indicators were less likely to develop cardiovascular disease. These findings were validated across cohorts in China, Europe and the United States.
Scientists have characterized how age and metabolism manifest in the microbiome.
Based on the results of a cohort study of more than 10,000 Chinese individuals, Chinese researchers developed a microbial signature associated with ageing and metabolism and validated it in a cohort of more than 9,000 Chinese individuals.
The researchers then looked at the effect of these characteristics on cardiovascular disease risk.
The researchers published their findings in the journal Nature Medicine.
The gut microbiome is a population of bacteria, viruses, and other microorganisms that not only play a role in digestion, but also in other processes such as nerve signaling, immune responses, and hormones.
Joshua Quinones, MD, a board-certified internist at The Medical Office in Manhattan, New York, who was not involved in the study, explained to Medical News Today:
“The microbiome influences cardiovascular disease risk by producing metabolites such as TMAO (trimethylamine N-oxide) and SCFAs (short-chain fatty acids), modulating inflammation and immune responses, influencing lipid and glucose metabolism, regulating blood pressure, and altering cholesterol absorption. […] As we age, changes in our immune system, diet, lifestyle and gut function alter our gut microbiome, resulting in fewer varieties of bacteria and altering how they work, affecting our overall health and risk of disease.”
First, the researchers studied a cohort of 10,207 Chinese participants, collecting information on 21 metabolic parameters to classify individuals into five “metabolic multimorbidity cluster” clusters. These were:
The researchers then examined the effect of belonging to any of these clusters on overall cardiovascular disease risk over an average follow-up of 11.1 years.
The researchers found that people in the obese and hyperglycemic groups were 75% and 117% more likely, respectively, to develop cardiovascular disease compared to those in the healthy group.
The MC1, MC2 and MC3 clusters were all associated with “healthy” parameters, whereas MC4 and MC5 were associated with “unhealthy” parameters. These results were validated in a cohort of 9,061 individuals with 10 years of follow-up.
The researchers then examined the gut microbiome of 4,491 participants from the original cohort and analyzed the genome sequences of the microbes they found there to identify the presence and abundance of specific species.
They found that the microbiomes of people who fell into the metabolic multi-disease cluster shared certain overlapping characteristics.
The researchers also characterized the species of bacteria found in the microbiomes of young and older people. They then plotted the presence of 55 age-associated microbes against age to develop an index of gut microbe age, which they then validated using existing cross-sectional data from Israel, the Netherlands, France, Germany, the UK and the US.
The microbiomes of younger people had lower levels of Bacteroides bacteria, while older people had higher levels of Prevotella and Enterobacteriaceae bacteria.
The study authors also noted microbial differences between individuals across countries, which they said could be an area for further research.
Further analysis showed that a younger microbial age was associated with a lower risk of cardiovascular disease.
The authors argue that this means that the microbiome may be a target for cardiovascular disease prevention in metabolically unhealthy older adults.
“The results are encouraging,” Katherine Lal, a Denver, Colorado-based registered dietitian and certified nutritionist for Happy V, who was not involved in the study, told Medical News Today.
“The results of this study show a strong correlation between poor gut microbiome health and increased risk of morbidities such as cardiovascular disease. This suggests that a healthy gut microbiome may help counteract the physical effects of aging, making it even more important in maintaining health as we age.”
“The idea that microbiome health correlates with a person's biological age has some merit, but the gut microbiome can also be significantly altered by prebiotic and probiotic supplementation, or even more extreme measures like fecal transplants,” she noted.
“We're not saying this demonstrates the ability to reverse aging, but it could definitely help improve the health of an aging population,” Lal said.
This finding is supported by evidence from other studies, which show that gut dysbiosis (an imbalance in the gut bacteria population) is associated with a variety of inflammatory diseases, including inflammatory bowel disease (IBD), rheumatoid arthritis, and systemic lupus erythematosus, as well as cardiovascular disease.
There is also a link between these conditions, including IBD, and cardiovascular disease.
While the study authors looked at heart attacks, strokes, and deaths associated with cardiovascular events, other studies have found that dysbiosis in the gut microbiome is associated with a range of cardiovascular risk factors, including atherosclerosis, high blood pressure, heart failure, chronic kidney disease, obesity, and type 2 diabetes.
But a core question remains: Do gut microbiota disturbances cause these problems, or do these conditions cause gut microbiota disturbances?
