What Is Gut Microbiota?

Imagine for a moment, a vast alien landscape littered with organic compounds. Pools of acid dot the landscape that is inhabited by hundreds of different organisms whose population measures in the trillions. Teams of ecologists, biologists, and geneticists scramble to find ways to quantify and understand the vast network of interactions between the organisms and their environment.

While this description sounds like the setting for some post-apocalyptic sci-fi film about an alien planet, it is actually taking place much closer to home…inside your digestive system in fact!

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Say Hello to My Little Friends

Scientists have long known that the human gut is the home to a variety of different species of bacteria, which play some role in human health. However recent research has revealed that not only is there a much greater number of microscopic inhabitants in our gut than we originally thought, but that the interactions between our bodies and those of our tiny symbiotic friends are much more complicated and have potentially greater impact than we ever realized.

Aside from the bacteria and viruses, various species of fungus have been found which not only live in our gut, but might also be involved in various autoimmune and metabolic diseases such as Crohn’s Disease and colitis.

It’s All About Balance

Something else that’s long been known about the tiny world of gut microbiota is that large populations of “good” bacteria help keep the growth of “bad” bacteria in check. When something happens to upset this balance, the harmful bacteria and fungi have a chance to run amok, and cause all sorts of trouble.

One of the most well-known cases of this is the bacterium Clostridium Difficile (or C. diff as it is commonly called), which can cause colitis. It is estimated that there are over three million C. diff infections contracted by patients in hospitals each year. While the C. diff bacterium is the actual vector of infection, certain antibiotics are considered the cause of infection because by wiping out large populations of bacteria in your gut, they pave the way for C. diff to take over.

Recent research has shown that there may even be a link between gut microbiota and obesity. And microbiologist Zhao Liping found that eating foods that are thought to promote the growth of “good” gut bacteria not only caused the good bacteria to flourish, but also caused the person to lose weight, lower his blood pressure, and lower his heart rate.

So how do we keep our internal balance in check? Let’s ask my colleague Monica Reinagel, the Nutrition Diva…

Monica, what can we do to keep our gut bacteria happy?

Thanks Lee! I’m happy to be here.

As we just learned, probiotics are friendly bacteria that normally inhabit the human digestive tract, where they perform all kinds of useful tricks—such as helping to digest our food and protecting us from harmful bacteria. Probiotic bacteria even manufacture vitamins for us—including vitamin K and B12. In fact, up to 3 pounds of your body weight actually consists of beneficial bacteria!

Although we often think of probiotics mostly in terms of dairy products like yogurt or kefir, there are all kinds of other probiotic foods as well. There’s Japanese tempeh or natto, which are both made from fermented soy. There’s Korean kim-chi, Polish sauerkraut and all kinds of other naturally fermented vegetables and pickles. Wine and beer both contain probiotics, and so does cheese—particularly aged cheeses like parmesan, cheddar, or gouda. In fact, virtually every traditional cuisine features some sort of fermented or cultured food.

It’s a good idea to include probiotic foods in your diet on a regular basis.

And although any one of these foods will supply beneficial bacteria, there good reasons to play the field. For one thing, there are many strains of beneficial bacteria and the various kinds of fermented foods feature different ones. These foods also have varying nutritional profiles and health benefits. Cultured dairy products provide a healthy dose of calcium, for example. Fermented cabbage and vegetables contain lots vitamins C, K and other nutrients. Wine contains polyphenols that are good for your heart. Beer is rich in B vitamins. Fermented soy products provide soy protein and isoflavones.

Just remember: Beneficial bacteria are only helpful if they’re alive when you eat them. Although freezing doesn’t kill bacteria, heat does. Foods like frozen yogurt, processed cheese, and pickles and sauerkraut in jars—which are pasteurized or heat-treated after they’re cultured or fermented—would not be considered probiotic foods.

Thanks Monica. That’s great advice.

Do you have any more questions about the organisms living inside your gut? Email me at everydayeinstein@quickanddirtytips.com, or follow me on Twitter, or check out my Facebook page. For more info on how to get probiotics into your diet, subscribe to Nutrition Diva’s podcast.

Come back next week for another episode of Ask Science’s Quick and Dirty Tips for Making Sense of Science.