Why caring for your microbiome is crucial if you want to live to 100

If you aspire to reach old age with good health, consider embracing the idea that you are not just an individual but a holobiont—a collaboration of human cells and the countless microbes living throughout your body.

This perspective is especially pertinent as we age, given that our microbiome evolves significantly over time. Recent research increasingly emphasizes the pivotal role that our microbial companions, both beneficial and harmful, play in promoting healthy aging. By nurturing this microbial community, we may unlock secrets to a healthier and longer life.

More than a century ago, the renowned zoologist Élie Metchnikoff postulated that the decline in vitality with age was due to toxic bacteria produced by putrefactive processes. He advocated for fermented foods and a simpler lifestyle as potential mitigators. This early notion has evolved, and today we recognize that our microbiome is intricately linked to our biological processes, affecting everything from digestion and metabolism to our cognitive functions.

However, understanding the microbiome’s full impact is no small feat. “The complexity of the microbiome rivals that of the human brain,” states microbiologist Filipe Cabreiro from Imperial College London.

Each person’s microbiome is uniquely their own, influenced by a myriad of factors including diet and lifestyle, and it can fluctuate significantly even within a single day. Collectively, researchers have made strides in identifying specific gut microbes that confer benefits versus those that can be harmful, revealing a critical insight: microbial diversity is essential for health. The greater the variety of microbes in the gut, the better our overall well-being tends to be.

Unfortunately, the aging process leads to a decline in the diversity and abundance of the beneficial bacteria that inhabit our guts. Older adults often consume less varied diets, take more medications, and experience fewer social interactions—all factors that adversely affect their gut microbiome. Research shows that even animals raised under identical conditions exhibit age-related shifts in their microbiomes, suggesting inherent biological changes associated with aging.

To delve into the consequences of this decline, many studies have concentrated on microbes that produce short-chain fatty acids (SCFAs) from dietary fiber fermentation. SCFAs play crucial roles in supporting gut lining integrity, suppressing inflammation, managing immune responses, and regulating blood sugar levels.

Inflammaging

As we age, the number of SCFA-producing microbes diminishes, while pro-inflammatory bacteria become more prevalent. “This imbalance may lead to a state of chronic, low-grade inflammation termed inflammaging, which is associated with a higher risk of conditions like cardiovascular disease, dementia, and stroke,” explains Jessica Schneider, chief scientific officer at Corundum Systems Biology in Tokyo, Japan.

Interestingly, the gut microbiomes of individuals who reach remarkable old age exhibit a surprising resilience against this decline. A pivotal 2023 study conducted by researchers Shifu Pang and Xiaodong Chen at Guangxi Medical University involved 1575 participants aged between 20 and 117. This study identified that the gut microbiota of centenarians closely resembled that of younger individuals, featuring greater diversity and a higher presence of beneficial bacteria from the Bacteroides phylum. “Our findings suggest that the microbiota profiles of centenarians mirror those of younger people,” the researchers concluded, proposing that this factor plays a role in longevity.

This revelation raises the intriguing question of whether we can foster our microbiome to age better.

Changing one’s gut microbiota is no easy task. “Introducing a complex community into another already established one can be quite challenging,” notes Cabreiro. Nonetheless, while prebiotics (which nourish beneficial microbes) and probiotics (live beneficial bacteria) may not dramatically overhaul the microbiome, they could provide beneficial nudges in the right direction, at least temporarily.

For example, a recent randomized trial by nutrition company Zoe demonstrated that their prebiotic, which contains 30 plant-derived nutrients, successfully increased beneficial gut bacteria and improved certain health metrics such as inflammation levels in the blood.

Additionally, a study involving 50 adults residing in nursing homes revealed that daily consumption of a prebiotic supplement containing fructooligosaccharides and inulin led to measurable improvements in frailty compared to a placebo group over a 13-week period.

Making dietary adjustments may also yield significant benefits. When older adults from various countries adopted a Mediterranean diet for a year, those who adhered most closely to it retained more microbial diversity and enhanced gut bacteria linked to healthy aging. This improvement correlated with better health outcomes, including increased walking speed, muscle strength, and memory retention as reported by Schneider.

More innovative treatments are also under investigation. Fecal microbiota transplants, currently approved for treating Clostridium difficile infections, show promise for additional conditions; however, the question of whether these methods can prolong lifespan remains speculative. Animal studies have demonstrated dramatic outcomes, such as older killifish living 37 percent longer after receiving microbiota from younger specimens, with similar results observed in mouse models.

Yet, researchers acknowledge that this field is still nascent. “We have a great deal to learn,” states Cabreiro. The interactions between microbial activity and biological pathways associated with aging—like those governing metabolism, mitochondrial function, and immune response—are complex and only beginning to be mapped. Approaches for manipulating the microbiome, whether through dietary interventions, pharmacological treatments, or even CRISPR gene-editing technologies, are emerging, stoking hope for future applications.

“While it’s still early days and we haven’t fully unraveled these interactions, the enthusiasm surrounding the potential impact on health and longevity is palpable,” concludes Cabreiro, highlighting the bright future that awaits as we deepen our understanding of our microbiome.