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How Carbohydrate-Rich Food Impacts Gut Health

Updated: May 30, 2022

Gut health is a hot topic. The subject of gut health is emerging in research, getting lots of media attention, and creating a probiotic boom on retail shelves through products like kombucha and kimchi. Search Google and you’ll find an overwhelming amount of articles with titles like “How to Heal Your Gut”, “Eat This to Keep Your Gut Happy”, "Healthy Gut, Happy Mind," and many more. There’s no denying that our gut impacts our overall health. All foods influence your gut microbiota, which is why the type of food you eat, including quality and source, matter. To understand the gut and how it impacts our health you’ll first need to know about the bacteria that populate it.

The gut contains three to five hundred species of bacteria. The dominant bacteria include Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria. These bacteria have been the subject of research as scientists aim to get a better understanding of the gut and the effects these species have on our health. For example, the ratio of Firmicutes to Bacteroidetes (the dominant bacteria found in the gut) has been examined in association with obesity. The bacteria in your gut can tell you a lot about what you eat and the overall state of your health.

What is “gut health”

The gut includes all parts of the digestive system starting with the mouth and salivary glands then moving all the way through the body to the rectum and anus. “Gut health” is the balance of bacteria in this tract and the ability for our gut to carry out all of its functions. Our digestive tract has many functions in the body including digesting and absorbing nutrients, supporting our immune system, creating or absorbing vitamins, and excreting waste. Digestive issues such as Crohn’s, Ulcerative Colitis, and Irritable Bowel Syndrome have been associated with an overpopulation of unhealthy bacteria in the gut and cause symptoms of discomfort and bloating after consuming a meal. We, as individuals, can help to populate the gut with a healthy balance of microorganisms through the foods we eat.

Because of emerging research demonstrating impressive impacts on health, scientists are actively studying the gut microbiome* and how it impacts our health and disease outcomes. An unhealthy gut has been linked to many diseases including type 2 diabetes, obesity, and intestinal diseases and it has also been shown to contribute to weight gain and increased blood sugar. A healthy gut contains bacteria that work together to protect the body against infections and viruses, reduce acute and chronic inflammation, and prevent lifestyle diseases. The gut also has direct communication with the brain through the gut-brain axis, influencing neurotransmitters, mood, and behavior. The gut can cause hormonal disturbances, stress, and anxiety simply because there’s an imbalance in bacteria. As you can see, the gut influences a lot of mechanisms without your body!

*The gut microbiome is the totality of microorganisms, bacteria, viruses, protozoa, and fungi, and their collective genetic material present in the gastrointestinal tract.


Carbohydrates, as we’ve discussed in previous blog posts here and here, can positively impact gut health, depending on the type of carbohydrate-rich foods that are being consumed. Carbohydrates are intact sugar units broken down into glucose (single sugar unit) and utilized by our body and brain for energy. Carbohydrate also includes fiber. The fiber component of carbohydrate is indigestible, meaning that our digestive enzymes do not break it down for energy. Instead, fiber travels through our digestive tract whole, into our intestines where it begins to ferment and produce beneficial bacteria, energy, and short-chain fatty acids. Short-chain fatty acids provide many health benefits including hormone synthesis, energy production, tumor inhibition, immune system support, and much more.

Fiber is found in foods like whole grains, vegetables, legumes, and fruit. The first line of defense in protecting the gut and fostering a healthy symbiotic balance of bacteria in the gut is to eat a sufficient amount of fiber. The minimum recommendation for women is 25 grams of fiber per day and for men is 38 grams of fiber per day.

Probiotics and Prebiotics for Gut Health

By now you have heard of probiotics. In fact, you may even be taking probiotic supplements. But have you heard of prebiotics? Perhaps you have seen them together, listed on supplement labels. Probiotics are strains of live microorganisms that populate the gut and are thought to improve health by restoring the gut flora. Foods that may contain probiotics include kimchi, kombucha, plant-based yogurt and kefir, miso, and some pickled vegetables. If you’re looking for foods containing probiotics, look for terms on the label like “live cultures” or “contains probiotics” or “unpasteurized” (pasteurization and heat kill the beneficial microorganisms).

The International Scientific Association of Probiotics and Prebiotics (ISAPP) defines “dietary prebiotics” as “a selectively fermented ingredient that results in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefit(s) upon host health.” (The host would be YOU!) Prebiotics are found in plant foods. Examples of foods high in prebiotic fiber include bananas, onions, garlic, berries, legumes, oats, millet, and asparagus. The prebiotics in these foods act as food for the probiotics and can help to grow the existing good bacteria.

Diets that include whole foods with a variety of fiber types and prebiotics, including legumes, whole grains, vegetables, and fruits, have been shown to increase good bacteria in the gut. On the other hand, low consumption of these foods has been associated with an imbalance of gut bacteria, resulting in more unhealthy bacteria in the gut that contributes to disease.

So why should you care?

Gut health can influence the overall health of an individual including brain function, immune function, metabolism, and more. What you eat can directly impact your health and improve your wellbeing.

By adding plant-based high-fiber foods, you can positively improve your health. Incorporating a variety of foods especially vegetables, beans, whole grains, fruit, nuts, and seeds, as well as foods with live probiotics, you can improve your gut bacteria.

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