Biology 101To some people, the idea of intentionally ingesting bacteria to treat ill health may seem nonsensical. After all, don't we try to rid our environments of bacteria to avoid getting sick? Turns out that bacteria have gotten a bad rap. "One of the things that's come to light recently is that the health of the body depends very much on the type of bacteria and the other microbes that live inside of it," says Gary Huffnagle, author of The Probiotics Revolution and a professor of internal medicine, microbiology, and immunology at the University of Michigan Medical School. "Bacteria are not only the causes of disease but also the cause of good health. It is a very different view of bacteria and germs than you usually hear about."
Trillions of microorganisms of various strains reside in the GI tract, from the stomach to the colon. According to Huffnagle, this is also where the immune system, the body's seat of overall well-being, is based. Here, deep in your gut, is where the power struggle for health occurs. When the body first detects harmful bacteria, either an overgrowth of harmful bacteria or invaders from the outside, it generates an immune response that both makes you sick and, ideally, kills the offenders. The body's reaction to beneficial bacteria is the opposite. Huffnagle says these good microbes calm the immune response not just in your stomach but all over your body, increasing your well-being and protecting you, in some cases, from harmful bacteria.
An imbalance in your GI flora occurs when the bad bacteria proliferate and crowd out the beneficial ones. Preliminary research has found that specific strains of beneficial bacteria, introduced in the form of probiotic-rich foods or supplements, can help correct an imbalanced bacterial environment and alleviate a range of symptoms associated with it.
For example, studies are investigating how probiotics may help treat maladies ranging from irritable bowel syndrome (IBS) and urinary tract infections to depression and diabetes. The National Institutes of Health is funding research on whether probiotics improve immunity. Meanwhile, other studies are looking at whether specific strains can alleviate eczema, reduce the symptoms of asthma, or even prevent cavities.
"There are 10 times as many bacteria in the human gut as you have cells in your body," says Steven Solga, an assistant professor of medicine at Johns Hopkins School of Medicine. "Half of the immune system, or maybe more, resides in the gut or circulates through it. So it stands to reason that there's a whole universe of potential importance to health in probiotics."
Balancing Act
A common cause of bacterial imbalance is the use of antibiotics—powerful medicines that kill not only their targets but almost everything else in their path, including beneficial intestinal bacteria. And since antibiotic use is so prevalent—scientists have found low levels of antibiotics in commercially raised meat and drinking-water supplies—you don't even have to take them to be affected."Think of your gut as a garden," says Dawn Motyka, a physician in Santa Cruz, California, who's had great results using probiotics for patients with IBS. "When you give antibiotics, you clear the ground and create fresh soil. If you aren't careful, the weeds—harmful bacteria—will move in. But if I add a ground cover— probiotics—on the bare dirt, weeds don't have a chance. If I keep feeding the ground cover, the weeds can't get in, and you have a healthy garden."
Another culprit in an imbalanced bacterial environment is the typical Western diet, which is rich in the things harmful bacteria feed on—refined carbohydrates and sugar—and often lacking in the soluble fiber that helps beneficial bacteria thrive. The result is an overabundance of harmful bacteria that can cause gastrointestinal problems such as constipation and, over time, bowel inflammation, as seen in conditions like Crohn's disease.
In addition, Huffnagle says that long-term bacterial imbalances act as irritants to the immune system in general, triggering extreme responses to normal stimuli. In fact, over time, a bacterial imbalance in your gut can lead to an overactive immune system and may contribute to the development of allergies or asthma, says Barry Goldin, professor of public health and family medicine at Tufts University School of Medicine.
Probiotics researchers, including Huffnagle, believe that in a generally healthy person, reducing those foods that feed the harmful bugs and adding more of the beneficial kinds can usually correct minor bacterial imbalances. Yogurt, fermented vegetables, and fermented cheese are all considered "high probiotic" products because they contain strains of beneficial bacteria that can help balance your intestinal flora.
Traditional health systems, such as Ayurveda and TCM, incorporate these good-for-you foods. Kimchi and miso, which are both high in probiotics, are staples of some Asian diets. And lassi, an Indian drink made from fresh yogurt, is commonly taken after Ayurvedic meals as a digestive, according to Nancy Lonsdorf, a medical doctor and Ayurvedic physician in Vedic City, Iowa. "In Ayurveda, good digestion is the key to health," she says. "And probiotics are an important part of the diet for the role they play in supporting good digestion."
Huffnagle believes we could all benefit from daily doses of probiotics. For most of us, one or two servings of yogurt or any probiotic-rich food should suffice. But if you struggle with chronic GI or other problems, food sources may not be enough. That's where probiotic supplements come in.
With supplementation, identifying the right strain for your needs is essential. Also, make sure that you choose a product with a high colony-forming unit (CFU) number; between 3 billion and 15 billion CFUs are necessary to affect the course of many illnesses. And choose freeze-dried capsules that are kept refrigerated to extend the product's shelf life, Huffnagle says. Also, beneficial bacteria aren't interchangeable. There are dozens of strains of Lactobacillus for instance, and each is believed to be helpful for a different condition, depending on what other bacteria are dominant in your body. However, it's unclear whether bacterial strains that alleviate a condition in one person will work for another, Huffnagle says.
"That's where the research is at right now," he says. "So experiment: Try a probiotic for a few weeks, and if it doesn't work, try another."
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