“All disease begins in the gut.”
― Hippocrates
What we choose to eat directly impacts both the character and quality of our internal minions, our individual gut microbiome. A healthy gut microbiota is a powerful ally in maintaining our health and wellness. Conversely, an unhealthy gut microbiome is increasingly recognized to play a significant role in gastrointestinal carcinogenesis.
Most disturbingly, a particular gastrointestinal cancer, colorectal cancer (CRC), has been increasing in incidence and prevalence over the last several decades. The trend has been particularly pronounced in those under 50 years of age, which is described as early-onset colorectal cancer (eoCRC), as opposed to average-onset colorectal cancer occurring in those 60 years of age or greater (aoCRC).
In addition to diet, lifestyle, and environmental factors can profoundly impact our gut bacteria and, subsequently, the functioning of our organs and cells. Metabolomics is the comprehensive study of metabolites within a biological system, such as the human body, its cells, tissues, or organs. Metabolites are small molecules that are the end products of cellular processes, and they include sugars, amino acids, lipids, nucleotides, and other small molecules that play critical roles in our physiology and metabolism. Metabolomics can be used to identify the alterations in chemical reactions at the cellular level resulting from diet, lifestyle, and environmental exposures and the changes that occur to the gut microbiome associated with such pathological processes as colorectal cancer.
This week’s study examined the feasibility of using metabolomics to identify host-microbiota correlations unique to those who develop early-onset colorectal cancer.
- The study examined 64 individuals with CRC; 20 with eoCRC and 44 with aoCRC.
- Approximately 60% of both groups were male, and the majority were Caucasian (100% of the eoCRC and 91% of the aoCRC).
- The tumors tend to be left-sided (85% eoCRC versus 68% aoCRC), with rectal carcinoma being the primary (65% eoCRC versus 39% aoCRC).
- The eoCRC group suffered more advanced disease, with 45% being Stage IV, versus 20% for aoCRC.
- The eoCRC group demonstrated 25 distinctive metabolites and ten distinctive microbial taxa.
- Using metabolomics measures, eoCRC and aoCRC were separated more efficiently than standard tumor measures.
Caveat:
This feasibility study demonstrated the independent and additive (when combined with traditional tumor markers such as CEA and CA19-9) benefit of incorporating metabolomics into the diagnostic armamentarium. It also indirectly highlights the critical role that diet plays in the prevention or development of colorectal cancer, particularly early-onset colorectal cancer.
However, there are several caveats. Other factors can impact the gut microbiota besides diet; the use of antibiotics is an obvious example. The study demonstrated that the gut microbiome only partially accounts for the differences between early-onset and average-onset colorectal cancer. The increasing incidence of eoCRC in the United States since the 1950s suggests additional players and a potentially significant role related to environmental exposures. Clearly, there are other important variables in this equation.
With that being said, of the potential gut microbiota species believed to play a role in the development of colorectal cancer (Fusobacterium, Anaeroplasma, Flavonifractor, Parasutterella, Rumino-coccaceae, UCG 002, Acidovorax, Anaeroplasma, and Eubacterium), Parasutterella and Ruminococcaceae UCG 002, stood out as particular risk factors for the development of eoCRC. However, as stated previously, this study was a feasibility trial. The bacteria mentioned and the other metabolites associated with eoCRC describe a metabolomic profile present after the disease is established. Thus, the study does not prove that any of these findings associated with eoCRC are causative. Nonetheless, this study portends an expanding world of new possibilities to study how our interactions with the systems and things around us, and how our choices regarding them, can ultimately impact our risk of disease and disability or our health and wellness; including what we choose to put on our plate.
The Study:
Additional resources:
