We’re taught from a young age that bacteria are bad — our soap is anti-bacterial, and we carry antibacterial hand sanitizer on key chains.
Only recently in medical history did scientists discover our own bodies are teaming with bacteria — on our skin, in our mouths and, quite obviously, in our bowels — that help us.
In 2012, scientists working on the Human Microbiome Project (HMP), a five-year study by the U.S. National Institutes of Health, were able to publish a complete database — a map, if you will — of the microbial makeup of a healthy human, finally giving researchers a reference point on which to base research on how changes in bacteria relate to health or disease.
And it turns out that a lot of what makes us human are the nonhuman entities living within us. There are more than 400 species of bacteria living in our guts, some of them “healthy” bacteria and some with the potential to cause damage. The healthy bacteria keep the damaging bacteria in check.
The presence or absence of certain gut bacteria can be linked to obesity, digestive problems and, in very recent findings, possibly our mental health. Much work is being done on how to balance these good and bad bacteria to relieve medical illnesses, and in some cases, particularly with digestive problems, it seems that balancing the bacteria in our guts may be as easy as eating the right kinds of foods.
Author and self-proclaimed fermentation revivalist Sandor Katz has made a career out of promoting the benefits of fermented foods: edibles that are preserved by microorganisms much like those living in our bodies. Katz has traveled the world teaching workshops that demystify fermentation with the hope that others will experiment with this ancient method of preserving food.
“Science and biology and medicine are just coming to recognize how important bacteria are to our overall health and well being, to every aspect of our physiology and functionality,” Katz says. “We need bacteria in our gut to affectively digest, to assimilate nutrients. Our immune system is mostly the work of bacteria. Our mental health — our brain chemistry, serotonin, other chemical compounds that determine how we think and how we feel — are regulated by bacteria in our intestines in ways we don’t fully understand. The ability of our livers’ cells to regenerate is regulated by gut bacteria. So many aspects of our functionality are tied up in these bacteria.”
Katz points out numerous factors in contemporary life that lead to lessened biodiversity in our gut: antibiotic drugs, antibacterial cleansing products and even processed foods, to name a few.
“We are subject to all of this exposure to chemical compounds that are designed to kill bacteria. They don’t kill all the bacteria in us but they diminish biodiversity,” Katz says. “So in this context, eating live culture fermented foods — foods which have undergone no heat process, haven’t been cooked after their fermentation so bacteria are alive and intact — is really just a strategy for improving overall health.”
Katz is careful, however, to say that eating a diet that regularly incorporates fermented foods isn’t necessarily a “cure” for everything.
“I feel like it’s a fine line; It’s not like we can say eating sauerkraut or drinking kombucha cures anything, and when people talk in those terms it makes me uncomfortable,” he says. “But I think that by improving all of these basic systems, eating foods that can improve digestion and immune function and perhaps improve mental health, that’s huge. It’s not the same thing as curing disease, but it can have a really positive impact in people’s day to day lives.”
Some of the first clinical applications for the Human Microbiome Project database involved studies on the digestive track, and with good reason: The U.S. Department of Health and Human Services estimates that between 60 and 70 million Americans deal with some form of digestive illness.
Clinical studies have looked at whether eating foods rich in natural bacteria, often called probiotics, could alleviate symptoms of digestive illness.
Irritable bowel syndrome, or IBS, has been one of the most extensively studied digestive illnesses where probiotics might provide a positive benefit. IBS is a common disorder that affects the large intestine, causing cramps, abdominal pain, bloating, gas, diarrhea and, alternately for some sufferers, constipation. While the exact cause of IBS is unknown, research suggests abnormalities in the gastrointestinal nervous sytem can create a poor connection between the brain and gut.
Two particular species of probiotics, Bifidobacterium and Lactobacillus species have been tested individually and in combination to determine affects on IBS, with much agreement between research projects that Bifidobacterium is beneficial for treating IBS.
Yogurt is famed for its live cultures that can aid in digestion — but the National Yogurt Association recommends looking for products with a seal indicating a minimum number of live starter cultures were used during fermentation. However, the seal doesn’t ensure that the yogurt contains probiotic bacteria or that there are large enough quantities of probiotics to have positive benefits. Luckily, making yogurt is a relatively easy process, and culture kits that contain Bifidobacterium are available for purchase online.
Other fermented foods contain bacteria that have been shown to be beneficial to balancing gut bacteria: Kefir and buttermilk also contain lacticacid producing probiotics, as do kimchi, sauerkraut and pickled vegetables. Any fermented vegetable that hasn’t been subjected to manufacturing processes can have probiotic effects: Miso, tempeh and umeboshi (a type of pickled plum), to name a few.
Katz says that a shift in American concern over where our food comes from and how it affects us has prompted a surge in interest for fermented foods outside of yogurt and sourdough bread.
“For any of us born in the U.S. in the 20th century, we were raised with the idea that bacteria was bad, period.” Katz says. “Since the first decoding of the microbiome, sort of these broader, cross-population studies of the microbiome … we understand now how bacteria are an important part of a strategy for staying healthy.”