If you have a healthy gut, you probably also have a strong immune system—and a healthy body (including radiant, glowing skin).

Our bodies are pretty active petri dishes: there's a mix of good and bad bacteria living inside each of us from our skin to our intestines. (Some estimates indicate that for each cell in our body—and there are many—there are 10 microbial, or bacterial, cells [1]. That means there could be trillions of bacteria inside our bodies.) It's no wonder the body with all these microorganisms is often referred to as "the human microbiome". (In fact, it's been estimated that the human body is composed of 10% of human cells and 90% of bacteria[ii].)

Nowhere is this more evident than in the gut. Bacteria line the intestines and help you digest food. During this process of digestion, they make essential vitamins, send signals to the immune system, and create small molecules that can help your brain function properly.

Researchers have determined that adding healthy bacteria into our bodies—through diet or supplements—can help reduce gas and bloating and increase regularity. Healthy gut bacteria can also help treat or prevent something called metabolic syndrome—a combination of risk factors that increase a person's chances of getting cardiovascular disease, diabetes, and stroke.[iii] (People with metabolic syndrome are twice as likely to develop heart disease and five times as likely to develop diabetes as the general population, according to the National Institutes of Health.)

"A healthy gut is also key to a healthy immune system. In fact, 70 to 80 percent of our immune tissue is located in the digestive system!"

But also, experts indicate that people with certain diseases often have a very different mix of bacteria in their intestines compared to healthier people[iv]. (Some bacteria can help strengthen the immune system[v] and even prevent obesity[vi] while others can promote inflammation.) And what's more, it's not one particular type of bacteria that makes a difference; it's a diversity of bacteria that's turning out to create a more healthful balance in the body.[vii]

> Benefits of Fermented Foods Cultures worldwide have been taking in healthy bacteria—or living organisms—for hundreds, if not thousands, of years typically through fermented local foods. (Fermentation helped preserve foods years ago, but many local cultures also made the link between these fermented foods and better health.) Here's a sampling of some of the indigenous foods different cultures ate (and, in some cases, still eat today):

During the Roman era, people consumed sauerkraut (essentially pickled cabbage); in ancient India, it was common to enjoy lassi, a pre-dinner sour-milk-based yogurt drink that's rich in healthy bacteria; in Bulgaria, people regularly drank fermented milk and kefir (also popular today); Ukrainians consumed healthy bacteria from raw yogurt, sauerkraut, and buttermilk (a fermented dairy product); and Asian cultures regularly ate pickled cabbage, turnips, eggplant, cucumbers, onions, squash, and carrots. All these foods are rich in local microorganisms that help balance out the gut.

"Some studies show that eating fermented foods, like sauerkraut (which is cabbage fermented with salt), actually helps prevent disease."

In studies of Polish women, researchers found that those who ate lots of sauerkraut had lower rates of breast cancer than those who didn't eat it (or ate much less of it) [x].

> Importance of Local Foods But just as early Mediterranean cultures taught us about the importance of a local, plant-based diet, these cultures have something to teach us about the importance of eating local foods. Some experts are now saying that local foods contain a diverse community of local microorganisms that are good for your particular digestion—and your gut overall—helping reduce gas and bloating and increasing regularity. The theory: each region has certain bacteria indigenous to the region and to the people in that region and can help these people stay healthy.

This idea of a healthy gut goes way beyond probiotics (which means "for life"), which are healthy bacteria—or live microorganisms—like lactobacillus, Streptococcus thermaphilus, and bifidobacterium that are often found in yogurt, kefir, some types of cheeses, and in many supplements. These probiotics have helped many people regulate their digestive system by creating a better balance of healthy bacteria in the gut (also called "intestinal flora").

The health of our skin also reflects this internal environment of our gut—as well as the balance of bacteria on our skin. We're quick to blame bacteria for causing problems like acne, but what many don't realize is we need a healthy balance of bacteria on the skin, too, for healthy, problem-free skin.

"Skin disorders like acne, rosacea, and psoriasis have been linked with gut problems (including food allergies and leaky gut syndrome)."

This may be why research shows that probiotics may help treat atopic dermatitis[viii], a type of eczema where the skin is super sensitive and is dry, scaly, and itchy.

The right balance of bacteria on the skin, too, contributes to the defense mechanisms of the skin (aka proper immune system functioning). That's why an imbalance on the skin—as in the gut—can contribute to conditions like atopic dermatitis, too[ix].

There's definitely something to this idea that bacteria—particularly local bacteria from the areas in which we live—is helpful to our health! So if you need even more reason to eat local, or add fermented foods to your daily diet, this is just one more, compelling reason.

Happy, healthy eating!

Resources:

[1] "What is Your Gut Telling You," Sonya Collins, WebMd.Com, August 20, 2014; http://www.webmd.com/digestive-disorders/news/20140820/your-gut-bacteria

[ii] "The Role of the Skin Microbiome in Health and Disease," Rodrigo Barros, MD Magazine, February 22, 2015; http://www.hcplive.com/conferences/aaaai-2015/The-Role-of-the-Skin-Microbiome-in-Health-and-Disease?e5=Email_md5&utm_source=Informz&utm_medium=HCPLive&utm_campaign=Trending%20News%202/22/15

[iii] "Metabolic Syndrome May Be Prevented By Healthy Gut Bacteria," David McNamee, Medical News Today, November 24, 2014; http://www.medicalnewstoday.com/articles/285962.php; Intestinal Epithelial Cell Toll-like Receptor 5 Regulates the Intestinal Microbiota to Prevent Low-Grade Inflammation and Metabolic Syndrome in Mice," Benoit Chassaing, Ruth E. Ley, Andrew T. Getwirtz, Gastroenterology, 2014, 147(6), 1363; http://www.pubfacts.com/detail/25172014/Intestinal-Epithelial-cell-Toll-like-Receptor-5-Regulates-the-Intestinal-Microbiota-to-Prevent-Low-g

[iv] "5 Claims About Probiotics and Good Gut Health," Houston Methodist, July 22, 2013; http://www.newswise.com/articles/5-claims-about-probiotics-and-good-gut-health

[v] "Gut Bacteria in Health and Disease," Eamonn M. Quigley, Gastroenterology & Hepatology, September 2013, 9(9): 560-569; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983973/

[vi] "When Obesity is an Inherited Trait, Maybe Gut Bacteria is the Link," Melissa Healy, LA Times, November 6, 2014; http://www.latimes.com/science/sciencenow/la-sci-sn-obesity-genes-gut-bacteria-20141106-story.html; "Human Genetics Shape the Gut Microbiome," Julia K. Goodrich, Jillian L. Waters, Angela C. Poole, et al., Cell, November 6, 2014, 159(4), 789-799; http://www.cell.com/cell/abstract/S0092-8674(14)01241-0

[vii] "How Bacteria in Our Bodies Protect Our Health," Jennifer Ackerman, Scientific American, 306(6); http://www.scientificamerican.com/article/ultimate-social-network-bacteria-protects-health/

[viii] "Probiotic 'Promising' to Prevent and Treat Atopic Dermatitis," Kate Johnson, Medscape Multispecialty Medical News, November 9, 2014; http://www.medscape.com/viewarticle/834650

[ix] "The Role of the Skin Microbiome in Health and Disease," Rodrigo Barros, MD Magazine, February 22, 2015; http://www.hcplive.com/conferences/aaaai-2015/The-Role-of-the-Skin-Microbiome-in-Health-and- Disease?e5=Email_md5&utm_source=Informz&utm_medium=HCPLive&utm_campaign=Trending%20News%202/22/15

[x] "Sauerkraut, Uncooked, May Prevent Cancer," Well Being Journal; https://www.wellbeingjournal.com/sauerkraut-uncooked-prevents-cancer/