Bacteria has long been synonymous with bad - the banners across hand sanitizer bottles proclaiming that it will kill 99.99% of bacteria reaffirm this idea each time we use it. While some bacteria are certainly harmful to our health, the microbiome is here to bring greatness back to the name of bacteria. If you haven’t yet heard about the microbiome yet, here are the basics:
After you swallow a bite of food, your mouth, stomach and small intestine work to break down carbohydrates, proteins and fats so that they can be absorbed and used by your body. But fiber remains largely untouched because your body cannot digest it on its own - instead it relies on 100 trillion bacterial cells lining the large intestine (aka the colon). Research on these bacteria is just beginning to unravel but thus far they have found thousands of strains colonizing our guts. The exact composition varies by person depending on diet, lifestyle and environment but research indicates that having a variety of strains is key for a healthy microbiome.
The fibers that fuel your microbiome are plant components that fall into three categories: soluble, insoluble or resistant starches. Soluble fiber is found in foods like oats, beans and peas, while insoluble fiber is found in things like the skin of fruits and whole grains. Resistant starches exist in seeds, green bananas and starchy foods that are cooked and then cooled (like potatoes).
the Microbiome behind the scenes
You might already know that fiber is beneficial because it keeps you moving but its most potent benefit is perhaps in feeding your microbiome, which performs a long list of highly important functions in the body. Various strains produce neurotransmitters (90% of your body's serotonin is produced by bacteria in the gut), enzymes, vitamins (B and K primarily), amino acids and short chain fatty acids. They also produce signaling molecules that regulate our appetite, satiety and digestion.
The immune system is another area for which the microbiome plays an integral role. One area of research points to the layer of cells that form the border into the body - the epithelial cells of the large intestine. Short chain fatty acids (SCFA) are produced as a byproduct of fermentation of plant fibers, which are then used by the epithelial cells lining the colon to both stimulate the immune system and reinforce the border. When SCFA are lacking because fiber is lacking, there are notable effects implications for immunity. The border begins to break down and low-grade inflammation is produced which chronically creates metabolic syndrome and a slew of subsequent diseases.
In that case, how should we consider antibiotics? There is no doubt that antibiotics have been extraordinarily helpful in combatting illness. But as microbial killers, taking antibiotics also means a wiping out major portions of your gut microbiome which can hold grave consequences for our health. While the microbiome can recover to an extent after antibiotic exposure, it decreases in its resiliency with each exposure. Antibiotics are also shown to be often overprescribed and unnecessary, so it is worth it to think twice before you take them.
Exposure antibiotics on a covert level is another concern - consider that farmers give antibiotics to their livestock in part in an effort to make them gain weight, which you then consume. Unsurprisingly, research has also linked antibiotic exposure to increases in obesity, allergies and asthma among other diseases.
Supporting the microbiome
So antibiotic exposure is a great concern and is best when minimized but it is difficult to avoid. How we can foster the health of our microbiome instead? Remember what feeds our microbiome: fiber. But studies indicate that only 3% of Americans meet their fiber requirement in their diets - meaning that 97% of Americans are deficient in fiber. As Stanford University microbiologist Justin Sonneburg puts it, it is like we are "starving our microbial self." University of Pittsburgh Gastroenterologist Stephen O'Keefe furthers this idea. He remarks, "The big problem with the Western diet is that it doesn’t feed the gut, only the upper GI. All the food has been processed to be readily absorbed, leaving nothing for the lower GI. But it turns out that one of the keys to health is fermentation in the large intestine." This is a revolutionary way to consider our diets - are we nourishing all parts of our body?
The quick and easy solution that has gained recent popularity is fiber additives in processed foods - you've likely had cereal, a granola bar or maybe even ice cream with added fiber. While any increase in fiber is a positive, it isn't the optimal choice. Again, the key to the microbiome is variety: a variety of bacterial strains and a variety of plant fibers from fruits, vegetables, legumes and grains to feed them. Fiber additives are typically only one or a few types of fiber, which at the end of the day isn't fostering the health of a diverse microbiome. Also consider that processed foods with added fiber are also rich in refined sugars which fosters the growth of bacteria that are non-beneficial, known as dysbiosis.
Sonya Angelone of the Academy of Nutrition and Dietetics underlines that these foods are also lacking the vast number of other nutrients that exist in plant foods - such as phytonutrients, antioxidants, vitamins and minerals - that "may contribute synergistically to the benefit of fiber itself." Research shows that the microbiome reacts swiftly to the composition of our diet, so it's never too late to include a variety of fibers from plant sources and support a diverse microbiome.
The bottom line
Your microbiome, comprised of 100 trillion bacteria from many strains, performs highly pertinent functions for your body. It benefits your digestion, immunity and nervous system directly and all other body functions indirectly. Research on the intricacies of the microbiome is in its infancy but largely it is clear that variety is important and antibiotics are harmful. A variety of fibers, directly from plant sources, are key to fostering a diversity of bacteria and happen to also include a slew of highly beneficial nutrients which are likely to act synergistically to support your overall health.
So why not make the effort to include more plants in your diet today? The health, happiness and harmony of your microbiome and body will thank you!