Healthy Gut, Happy Gut — How Probiotic Bacteria Can Benefit You
by Natasha Trenev
The idea that the bacteria that live in the warm, dark recesses of your gut have health beneﬁts is an intriguing one. After all, most people think bacteria are the “bad guys.” These days, it’s clear that not all bacteria cause illness and some types of bacteria you might actually want to have around. The “good” bacteria you want to cultivate help support the health of your gut and your gut associated lymphoid tissue — the portion of your immune system that lies in your intestinal tract. After hearing so much about the health beneﬁts of gut-friendly bacteria, called probiotics, you’re probably convinced you need more of the beneﬁcial ones — but why? How do probiotic bacteria exert their beneﬁts?
Probiotic Bacteria Aid Digestion
As you know, your intestinal tract is where the nutrients you take in through diet are absorbed. However, only some of the food components that enter your digestive tract can be broken down and absorbed by your body. Humans lack the enzymes to break down some types of plant material. Some of the ﬁber and resistant starch you can’t digest conveniently becomes lunch or dinner for bacteria that live in your gut.
When these hungry gut bacteria break down the ﬁber for you, they produce compounds called short-chain fatty acids, two of the most common of which are butyrate and acetate. These compounds help keep the lining of your colon healthy. The cells in your colon use these short-chain fatty acids to produce the energy they need to fuel the functions necessary to keep your colon healthy. Some preliminary studies suggest short-chain fatty acids made by good gut bacteria might lower the risk of colon cancer. Production of short-chain fatty acids by gut bacteria may partially explain why high-ﬁber diets seem to offer some protection against this.
Probiotic Bacteria Help Balance the Gut
When probiotic bacteria produce short-chain fatty acids, it also lowers the pH or acid-base balance of the lining of your intestinal tract. That’s beneﬁcial, since disease-causing bacteria typically don’t grow well in an acidic environment. Therefore, probiotic bacteria create a hostile environment that discourages the growth of bacteria that cause illness. Probiotic bacteria can also block the growth of sinister bacteria by competing for the resources they need to survive. When good bacteria are around they use up vital nutrients, making it harder for bad bacteria to get the nutritional components they require to stay alive. Some probiotic bacteria produce substances called bacteriocins that directly block the growth of harmful bacteria, as well as chemicals like hydrogen peroxide, that stymie the development of bad bacteria and yeast.
Probiotic Bacteria and Absorption
Probiotic bacteria also produce beneﬁcial substances. These organisms release enzymes that break down components from the foods you eat so you can absorb them more easily. In addition, the acidic environment probiotic bacteria create, increases the absorption of minerals, including calcium, magnesium and zinc. Having a healthy population of gut bacteria helps you maximize absorption of these essential minerals.
Probiotic Bacteria and Immunity
Another way probiotic bacteria exert their beneﬁts is by their effects on immune function. Your immune system is your ﬁrst line of defense against viruses, bacteria and fungi and plays a protective role in many diseases. As researchers point out, one of the reasons older people have a harder time ﬁghting off infection is that their immune system doesn’t function the same as that of a younger person. We know that a huge portion of your immune system, between 70% and 80%, is in your gut, making it the largest immune organ in your body. Gut bacteria have the ability to communicate with immune cells and inﬂuence their function, giving them the capacity to subtly alter immune function.
Research suggests probiotic bacteria help maintain immune balance as well. Your immune system is designed to launch an organized attack against foreign invaders, but an overly zealous attack can harm normal tissues, leading to inﬂammation. Probiotic bacteria help preserve immune system balance.
Because some food allergies involve an overreaction by the immune system, there’s thought that probiotic bacteria could help children avoid food allergies. More recently, some experts point out that some food intolerances, which are different from a food allergy, may be due to a damaged gut lining, also known as a “leaky gut.” The lining of your gut is very thin, only a single cell layer thick and is held together by connections called tight junctions, which are easily damaged. When the gut lining and its tight junctions are injured, which can happen when you take certain medications or due to stress, it allows food components and even bacteria to enter your bloodstream. These proteins, once in the bloodstream, can theoretically activate the immune system and lead to inﬂammation and tissue damage. By helping maintain a healthy gut lining, probiotic gut bacteria could be beneﬁcial for people with food sensitivities, intolerances and for leaky gut. The lining of your digestive tract serves as a barrier that protects you against bacteria and other harmful components in the food you eat and probiotic bacteria help to strengthen this barrier function.
Bacteria “Talk” to Each Other
Another interesting way probiotic bacteria may beneﬁt your intestinal health is by the messages they send to bad bacteria. Infection-causing bacteria communicate with each other through a process called “quorum sensing.” Through this form of communication, bacteria get a better idea of what’s going on around them. For example, the bacteria in your gut want to know whether there are enough nutrients to support their growth. If there’s a lack of nutrients, they slow their replication to ensure their survival.
Research suggests some types of probiotic bacteria have the ability to block communication pathways bad bacteria use to “talk” to each other. When infection-causing bacteria can no longer communicate with each other, their chances for survival drops because they’re less aware of what’s going on around them. Blocking communication pathways between bad bacteria is a way to limit their growth and survival.
In addition, communication between good bacteria can be beneﬁcial. For example, probiotic bacteria have the ability to enhance the growth of other good bacteria within the ecosystem. One species of gut-friendly bacteria might send a message to another species of probiotic bacteria, letting it know conditions are favorable and to reproduce more. As a result, your gut becomes healthier.
The Bottom Line
Despite the fact that the research explaining how probiotics work is still in its infancy, their health-related beneﬁts have been noted for hundreds of years. Research continues to uncover the characteristics and habits of the probiotic bacteria that live in our gut and it’s exciting to better understand exactly how they are beneﬁting us and how we can supplement this unique eco-system within our bodies. Having a healthy population of gut bacteria is essential for optimizing your health. Don’t underestimate the potential of your gut bacteria.