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What do our gut microbiomes have to say about how we age? Image credit: Westend61/Getty Images.
  • Measurements of metabolic health can be used to evaluate the risk of developing cardiovascular disease.
  • Researchers in China have also shown that metabolic health can be characterized by the presence and abundance of certain microbes in the gut microbiome.
  • Age is also associated with certain characteristics of the microbiome and people with microbiomes associated with younger metrics were less likely to experience cardiovascular disease.
  • These findings were verified across Chinese, European and American cohorts.

Scientists have characterized the way age and metabolism can present in the microbiome.

Researchers in China developed an age-related and metabolism-related microbial signature based on findings from investigations in a cohort of over 10,000 Chinese people, and verified it on a cohort of over 9,000 Chinese people.

They then looked at the impacts these signatures had on cardiovascular disease risk.

The researchers published their results in Nature Medicine.

The gut microbiome is the population of bacteria, viruses and other microbes, playing a role in digestion, but also in other processes, including nerve signaling, immune response and hormones.

Yoshua Quinones, MD, a board-certified internist with Medical Offices of Manhattan, NY, not involved in this research, explained to Medical News Today:

“The microbiome affects cardiovascular disease risk by producing metabolites like 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 the gut microbiome. This leads to fewer different types of bacteria and changes in how they work, affecting our overall health and risk of diseases.”

First, the researchers looked at a cohort of 10,207 Chinese participants, collecting information on 21 metabolic parameters to classify individuals into five “metabolic multimorbidity clusters” clusters. These were:

They then looked at the impact of being in one of these clusters on overall cardiovascular disease risk over an average follow-up of 11.1 years.

They discovered that people in the obesity and hyperglycemia clusters were 75% and 117%, respectively, more likely to develop cardiovascular disease when compared to the healthy cluster.

The MC1, MC2, and MC3 clusters were all linked to “healthy” parameters, while MC4 and MC5 were associated with “unhealthy” parameters. These results were then validated in a cohort of 9,061 individuals, with a 10-year follow-up.

Researchers then looked at the gut microbiome of 4,491 participants from the original cohort, and sequenced the genomes of the microbes found there, to identify the presence and abundance of particular species.

They discovered that the microbiomes of people they assigned to the metabolic multimorbidity clusters had certain overlapping characteristics.

They also characterized the species that were found in the microbiome of younger people and older people. They then plotted the presence of 55 age-related microbial species against age to develop a gut microbial age metric, which they then validated using existing cross-sectional data from Israel, the Netherlands, France, Germany and the United Kingdom and United States.

The microbiomes of younger people were associated with lower levels of Bacteroides species and older people had higher levels of Prevotella and Enterobacteriaceae species.

The study authors also pointed at microbial variation between individuals in different countries, and stated this could be an area for further research.

Further analysis showed that a younger microbial age was associated with lower cardiovascular disease risk.

The authors have argued this could mean the microbiome could be a target for cardiovascular disease prevention in older adults who are not metabolically healthy.

Catherine Rall, RDN, a registered dietitian based in Denver, CO, and certified nutritionist at Happy V, who was not involved in the research, told Medical News Today that:

“The results of this study show a strong correlation between poor gut microbiome health and an increased risk of morbidity-related conditions like cardiovascular issues. This suggests that a healthy gut microbiome can help to limit the impacts of aging on the body, becoming even more important in helping people stay healthy as they age.“

“While there is some merit to the idea that microbiome health can correlate effectively with someone’s biological age, our gut microbiomes are also highly changeable through prebiotic and probiotic supplementation and potentially even more extreme measures like fecal transplantation,“ she noted.

“I wouldn’t say that this represents our ability to reverse aging, but it can definitely help to improve health outcomes in people as they age,” said Rall.

The findings of this research are backed up by evidence from other studies, which have shown that gut dysbiosis — imbalance of bacterial populations in the gut — is associated with a range of inflammatory conditions, including inflammatory bowel disease (IBD), rheumatoid arthritis, and systemic lupus erythematous, but also cardiovascular disease.

There are also links between those conditions, including IBD, and cardiovascular disease.

The authors of this study looked at heart attack, stroke, and death related to cardiovascular events, but other studies have linked gut dysbiosis to a range of cardiovascular risk factors, including atherosclerosis, hypertension, heart failure, chronic kidney disease, obesity, and type 2 diabetes.

However, the core question remains: Does dysbiosis cause these problems or do these conditions cause dysbiosis?