Got a gut feeling? Well, you may be right!
Human beings have been on planet Earth for about 200,000 years. However, a shocking fact is that 98% of human existence has passed, with an average life span of only 19-25 years. 1 The exponential growth in science and medicine over the last two centuries has greatly increased our life expectancy.
Research has been conducted in the past decade focusing on factors that determine aging, longevity, and the ability to adapt to environmental influences. One factor associated with aging is the microbial composition of our gut. Through this research, scientists will be able to detect your age through only your stool samples. 2
Your gut microbiome changes over time
Researchers study bacteria in our digestive systems across large groups of people for various reasons. One reason is to understand the changes in the bacteria over time. These studies include people of multiple ages, ethnicities, and environmental exposures. The results are fascinating. They suggest that, as we age, our gut microbiota evolves and adapts to the requirements of that phase of our lives. 1,2
The research team from the University of Bologna, Italy, and their leader, Sara Quercia, conducted one of these studies. It focused on changes in the gut microbiota in humans with variables including age, daily life practices, genetic condition and physiology of the person, and dietary shifts. 3
For example, by design, the gut microbiota boosts the immune system, brain development, and nutritional absorption during infancy. But, for a senior, the gut microbiota enhances energy intake by breaking down complex sugars. 1
We are all born entirely sterile, but within a few hours of birth, microbes start living inside us. The incredible journey through the birthing canal is the first step that initiates a complex relationship between our gut and the tiny beings that will continue to aid us for the rest of our lives. Interestingly, some studies have tried to see if there is any relation between this “pioneer microbiome” across different modes of birth.4
Discoveries showed babies delivered vaginally absorbed microbes from the mother’s birth canal. Those born through cesareans were found to have the same microbes as on the mother’s skin. The first “pioneer microbiome” usually consists of facultative aerobes. However, as the infant consumes breast milk, the gut microbiota changes to obligate anaerobes.
As infancy ends, the gut microbiota slowly starts resembling an adult's. Some argue that a mature adult's gut microbiota might even attain some stability. However, it is well established that an elderly gut holds more aero-tolerant and pathogenic species. Because there are more of these types of microbes, extra energy is needed to break down sugars into energy for the body. This factor leads to age-related diseases. 4
Where you live and what you eat could affect your microbiome
Professor Yatsunenko from the Center for Genome Sciences and Systems Biology at the Washington University School of Medicine conducted an interesting study. They characterized gut microbiota from 531 people living in three different countries. 5 He, along with his co-authors, noticed that across these three groups, the way the infant gut microbiota developed remained comparable. But, there were clear differences between the microbiota assemblage of those from the USA and the other two countries. He speculates that the effects of westernization and varied diets could be the reason behind this.
Another group of scientists from the Center for Microbiome Innovation at the University of California, San Diego, analyzed over 11,000 stool samples for the American Gut Project.6 This study shows that those who eat a larger variety of vegetables have a much more diverse gut microbiota compared to those who eat fewer and less variety of vegetables. Also, eating different vegetables seems to help us metabolize food in more than one way.
Is there a link between aging and the gut microbiome?
Looking back at these studies, we can see scientists often tend to pose a question that might be slightly difficult to answer. While it is true that gut microbiota can reveal your age, could it also be true that your aging process is governed by what's in your gut? Therefore, it is vital that one takes care of the microbes living in the digestive system and always listens to their gut.
References
Valle Gottlieb, M. G., Closs, V. E., Junges, V. M., & Schwanke, C. H. A. (2018). Critical Reviews in Food Science and Nutrition, 58(9), 1557-1564.
O'Toole, P. W., & Jeffery, I. B. (2015). Science, 350(6265), 1214-1215.
Quercia, S., Candela, M., Giuliani, C., Turroni, S., Luiselli, D., Rampelli, S., Brigidi, P., Franceschi, C., Bacalini, M. G., Garagnani, P., & Pirazzini, C. (2014). Frontiers in microbiology, 5, 587.
Galkin, F., Aliper, A., Putin, E., Kuznetsov, I., Gladyshev, V. N., & Zhavoronkov, A. (2018). bioRxiv, 507780.
Yatsunenko, T., Rey, F. E., Manary, M. J., Trehan, I., Dominguez-Bello, M. G., Contreras, M., Magris, M., Hidalgo, G., Baldassano, R. N., Anokhin, A. P., & Heath, A. C. (2012). Nature, 486(7402), 222.
McDonald, D., Hyde, E., Debelius, J. W., Morton, J. T., Gonzalez, A., Ackermann, G., Aksenov, A. A., Behsaz, B., Brennan, C., Chen, Y., & Goldasich, L. D. (2018). mSystems, 3(3), e00031-18.
