The world population is getting older, with average life-expectancy creeping up across the globe. By 2020, the number of elderly people will outnumber the number of young people globally, and this demographic shift has already occurred in many countries in the developed world.
With the rise of the number of older people, medical focus has turned to improving health as they age. It is not enough to merely live longer, but people want to be able to prevent age-related disease to live happy, healthy and productive lives well into advanced old age. Not only do we want that for ourselves, but our economy depends on it. A relatively small demographic of younger, working people cannot support a much larger group of non-working, sick older adults for long without bleeding society dry.
The science behind what causes physical and mental changes as we age, and why some people stay much healthier than others as they get older, is poorly understood. Like so many other areas of medical science that are focusing on the microbiome as the source of a wide range of health problems, geriatric research is also looking to the gut for medical advancements.
Could Inflammation be a Major Factor in Aging?
Inflammation in the body increases over time and is believed to be a cause of many age-related health problems. There is significant medical evidence that chronic, low-grade inflammation is underlying factor in both general aging as well as in many age-related diseases. In fact, both aging and inflammation are considered as associated factors in a wide range of diseases that can affect almost all organs in the body.
Inflammation is the body’s natural response to disease or injury. In a normal, well-functioning immune system the body creates a localized response aimed at promoting healing and destroying pathogens, getting the affected organ back to full operation quickly. In its initial phase, inflammation causes heat, pain, swelling, redness and loss of functioning. In a healthy individual, such inflammation resolves quickly, but in older people, the body’s ability to modulate the inflammation is reduced and the body stays in an inflamed state after the initial response is no longer needed.
The body releases chemicals as part of the inflammatory process. These chemicals have been observed in older adults, even in the absence of disease or injury. Their presence shows that inflammation is present.
It is believed that chronic inflammation plays a role in many age-related diseases such as diabetes, cardiovascular disease, dementia and even osteoporosis and general frailty.
What Role Does the Microbiome Play in Inflammation and Disease?
One of the most important protective roles the healthy, commensal microbes perform in in our digestive tracts is regulating inflammation. They work to suppress an inflammatory response to food or other non-harmful substances that enter the body through breathing or eating. They help to regulate the body’s response to acute inflammation following injury or illness. Our immune system cannot function at peak performance without these helpful microbes.
A wide range of diseases and health conditions have been linked to an unhealthy gut microbiome, such as “bowel conditions (irritable bowel syndrome, Crohn’s disease, and colon cancer, neurological diseases (Parkinson’s disease, Alzheimer’s disease, and multiple sclerosis)) metabolic diseases (obesity and diabetes), as well as musculoskeletal conditions (frailty, osteoporosis, rheumatoid arthritis, and gout)”. The incidence of these diseases goes up over time as people age.
As they age, people typically lose overall numbers and diversity of microbes in their digestive tract slowly over time. There is also an increase in chronic inflammation and higher risk of disease linked to unhealthy microbiomes. Because of the known role a healthy microbiome plays in calming inflammation and the role that a disturbed microbial mix can play in development of diseases associated with older age, it seems worthwhile for scientists to examine the role that the microbiome plays in the physical effects of aging.
Exceptionally Healthy Seniors Have Youthful Microbiomes
Having numerous and diverse species of microbes in the digestive tract is a sign of a healthy microbiome. As mentioned above, studies have shown that people’s gut microbiomes generally degrade as they age, losing both number and diversity of healthy microbes, thus leading to inflammatory disease. A recent study has supported the theory that the microbiome is a factor in aging, finding that unusually healthy senior citizens have microbiomes as diverse and healthy as people in young adulthood.
A study published in the American Society of Microbiology titled, “The Gut Microbiota of Healthy Aged Chinese Is Similar to That of the Healthy Young”, published in 2017 reveals a very intriguing correlation between the gut microbiome and aging. This study, one of the largest microbiota studies done to date, has shown a potential link between a healthy microbiome and aging exceptionally well.
Unlike the past studies looking at the microbiomes of people as they age, this one looked only at very healthy people of all ages, rather than a random cross-section of elderly adults and found that a loss of diversity and health in the microbiome is not inevitable over time. Researchers evaluated 1000 very healthy Chinese people, aged from 3 to >100 years old with no known illness and no family history of disease.
These fortunate folks did not show the typical loss of vitality in the microbiome that is typical for older people. Using fecal samples, researchers examined both the overall numbers of microbes living in the digestive tract as well as the diversity of species found there. The very healthy elders examined, researchers found, had microbiomes that were just healthy as healthy adults in their 30’s. For these lucky, healthy older folks, their microbiomes seemed to stay stable throughout their long lives, unlike for their less healthy peers.
What, if anything, does this mean or the science of aging? It doesn’t prove causation – meaning that this study only shows a correlation between a healthy stable microbiome and extreme health in old age. Nor does it prove that being a healthy senior promotes a healthy microbiome. Gregor Reid, PhD, of Western’s Schulich School of Medicine & Dentistry and Scientist at Lawson Health Research Institute, one of the researchers says, “It begs the question – if you can stay active and eat well, will you age better, or is healthy aging predicated by the bacteria in your gut?” The researchers concluded, based on their results, that, “our results suggest that diet and lifestyle choices consistent with healthy aging even into the 10th decade of life include a healthy and diverse microbiota.” Regardless, a healthy microbiome is at a minimum a marker of healthy aging such as blood pressure or cholesterol readings are.
Does a Healthy Microbiome Promote Healthier Aging?
Even without knowing the cause behind these correlation, the connection between healthy old age and a diverse, young-appearing microbiome is intriguing because we know how many healthy benefits a well-functioning microbiome can provide and we know that disturbances to the microbiome can lead to disease. Studies have shown that a loss of diversity of healthy microbes in the gut is associated with increased frailty and impaired cognitive performance in the elderly.
The microbiome is an integral part of our immune system, calming inflammation and helping to fight off disease causing pathogens. It aids in digestion, helping the body to extract energy and nutrients from our diets. Microbes can influence weight-control, thus promoting the benefits that go along with maintaining a healthy weight. Our healthy gut bugs also can increase mental health but reducing anxiety, depression and obsessive behaviors. Improved mental functioning can lead to happier and more productive lives in the senior years. All of these benefits are valuable and would certainly contribute to a happier and healthier old age.
More research needs to be done to tease out whether healthy old age promotes a “young” microbiome or whether a “young” microbiome causes healthy aging (or whether a third factor is at work). One can imagine future studies that evaluate what effects there are on aging to improving the health of the microbiome at different phases of human life. This could include minimally invasive interventions such as including more fiber or fermented food in the diet to more invasive procedures such as performing fecal transplants on elderly people with fecal donations from extremely healthy younger adult donors. If those adults who receive gut-altering treatments develop fewer diseases associated with aging than their control group who do not improve their gut health, this would be incredibly exciting.
But these sorts of studies are very expensive to run and will take many decades to conclude.
What Do We Know and What Does It Mean?
We know some very intriguing pieces to the aging puzzle:
- Chronic inflammation increases with age.
- Chronic inflammation can trigger disease.
- A healthy microbiome modulates chronic inflammation.
- The incidence of diseases caused by chronic inflammation increase with age.
- Microbiomes degrade as we age, losing diversity and numbers of good microbes.
- Disturbed microbiomes lead to higher rates of certain disease.
- A loss of diversity in the microbiome is associated with increased dementia and frailty.
- Unusually healthy elderly people have very healthy microbiomes (similar to a decades younger person).
All of these known factors together lead to the hypothesis that as microbiomes lose healthy microbes over time, the body becomes less effective at controlling inflammation, thus leading to the diseases and infirmities of old age. If this hypothesis is true, that leads to a key area for further research to determine if supporting and improving microbiome health will lower incidence of age-related diseases and their negative effects.
Although the current state of medical knowledge cannot state with certainty that promoting and maintaining a healthy microbiome across the course of one’s life will lead to greater health in older age, there is enough evidence to suggest this may well be true. There are many very smart researchers exploring the possibility that disturbances to the microbiome, which increase over time, are contributing to diseases of aging.
Given that there is no down-side to improving gut health, and given what we already know from the study on Chinese elders, it seems like a very worthwhile investment to take all necessary steps to promote a healthy microbiome. This includes eating a diverse diet of fiber rich foods. It means including fermented food as a regular part of the diet. It means avoiding unnecessary antibiotics and chemical food-additives. The earlier in life this can be started, the more potential it has to prevent or reduce disease later in life if there is in fact a causal relationship. There are so many benefits to improving the health the of the microbiome, that even if it is not guaranteed to lead to a better quality of life in old age, these steps will increase overall mental and physical well-being in the nearer future.
If it can be shown that maintaining an existing healthy gut microbiome can lead to a healthier old age, or that making improvements the gut microbiome can lead to overall health improvements for older people, this can lead to the development medical interventions aimed at the microbes in the gut that will improve people’s lives across their lifetimes.
I followed a gut bacteria diet last year and since then have gone low carb and now ketogenic. I started personalized testing of my blood sugar and found that a lot of the gut bacteria foods were spiking my blood sugar so I have cut them out. Is there a way of combining the two. I do make home made kefir but of course that has milk is so I have been told not suitable for keto