Did you know that there are more bacteria in your intestine than there are cells in your body? Unbelievable, right? Moreover, it turns out that these bugs actually contribute to health and disease. This is a hot topic in the scientific world and it turns out that a lot of nutrition scientists are quite interested in this area of research. What then, you might ask, is the link between nutrition and gut bacteria (or the so-called ‘gut microbiota’), and how exactly do they influence one’s health and well-being? Great questions! Let’s explore these concepts.
In a healthy person, most nutrients are digested and absorbed in the small intestine. This includes mono-and disaccharides (i.e. simple sugars), amino acids derived from dietary proteins and fats. Complex carbohydrates, such as soluble and insoluble fibers and resistant starches, however, cannot be digested by human enzymes and enter the large intestine (or colon) intact. This also happens to be where the bulk of bacteria reside. Interestingly, the gut microbes can then digest soluble fibers and resistant starches in the colon. Some of the breakdown products of these complex carbohydrates, called short-chain fatty acids (for example, butyrate), provide fuel for the cells lining the colon (as well as providing fuel for the bacteria that digest them). These dietary constituents have been termed ‘prebiotics’ as they feed the gut microbes. The amount of fiber in your diet can actually alter the composition of the gut microbiota, by promoting the growth of certain types of bacteria.
There are literally dozens of different bacterial species in the human intestine, some are beneficial to us and others can be harmful under certain conditions. It turns out that changes in the composition of the gut microbiota can increase the risk for: functional bowel disorders, inflammatory bowel diseases, celiac disease, food allergies, type 2 diabetes, obesity, autism and even depression (Science Daily Article).
So, consumption of prebiotics is one way to positively influence the gut microbiota. Are there others? Yes, probiotics. Probiotics are living bacteria that can be found added to certain foods in the grocery store. The probiotic bacteria added to these foods populate the gut with good bacteria and, in principle at least, outcompete the bad bacteria, tipping the balance towards health. Probiotics have been suggested to improve resolution of diarrhea, prevent and treat urinary tract infections, treat irritable bowel syndrome, reduce bladder cancer recurrences, and prevent or reduce the severity of colds and flu (amongst other purported benefits).
So then, are you kind to your intestinal co-inhabitants by feeding them nutritious snacks (i.e. complex carbohydrates)? Or are you, like most Americans, not consuming enough fiber in your diet. How about probiotics? Do you consume foods with beneficial live bacteria? They are available at your local grocery store right now. If you answered no to these questions, you might want to think about this issue. It could positively influence your health in ways that we currently understand and in other ways that will undoubtedly be discovered in the future.