We've gone from nuking the teeming trillions of bacteria that populate our bodies with poison soaps and hand sanitizers to worshipping them, especially those that live in our gut. Probiotic supplements are a 40-billion-dollar-a-year-industry (and growing). Their popularity isn't all that surprising given that they have been hyped as a cure-all for everything from eczema to irritable bowel syndrome to obesity.
In the scientific community, there's a great deal of interest in studying the microbiome and its impact on health. But does that mean we all should be popping a daily probiotic-in-a-pill to boost our intestinal flora? Probably not says Matthew Ciorba, a gastroenterologist and director of the Inflammatory Bowel Disease program at Washington University in Saint Louis.
Despite the hype, he explains that most probiotics supplements marketed today have not gone through any clinical trials nor been tested by the FDA. That doesn't mean that probiotics are useless or ineffective, it's just that consumers need to be aware that there are a lot of claims made by supplement companies that aren't backed by science.
The first thing to understand about probiotics is that they encompass many strains which impact the body in different ways. For example, gastroenterologists may recommend the well-tested supplement Align, which contains bifidobacteria to women who have irritable bowel syndrome. For patients who are suffering from diarrhea related to a course of antibiotics, several strains of Lactobacillus and the probiotic yeast Saccharomyces boulardii can be helpful. These are found another reliable supplement, Culturelle. The bottom line is that if you are hoping to treat a medical condition with a supplement, speak with a specialist about which strains are actually proven to be effective and if they can recommend a particular brand.
What about the rest of us who want to reap the potential benefits of probiotics? The answer is diet. For hundreds (if not thousands) of years, humans have safely eaten fermented foods rich with beneficial bacteria. Great sources are yogurt and cottage cheese, kombucha, sauerkraut and kimchi, salt-brined pickles, miso, raw apple cider vinegar, and tempeh. With such a variety, it's not hard to eat some every day.
Eating soil based organisms (SBOs) is another buzzy concept. It's theorized that our overly sanitized environments have contributed to the increase in allergies and other immune system disorders and that we should consume more dirt. These bacteria are thought to be more resistant to the stomach acids that may kill some of the probiotics we get from fermented foods. Some companies are now marketing supplements containing SBOs. Again, while the idea of a "magic bullet" —or pill that can transform your health—is tantalizing, experts say it's safer to be exposed to these bacteria the old fashioned way: by avoiding antibacterial products and eating organic fruits and vegetables, especially those that come from a trusted farm stand so you don't have to wash excessively.
You also need to feed those gut bacteria—remember, they are living things too. Beneficial bacteria thrive on fiber, what nutritionists call "prebiotics." A diet rich in fiber can fight chronic disease, reduce inflammation, boost the immune system, and combat obesity. High fiber foods, such as fruits vegetables, legumes, and whole grains have the added benefit of being loaded with vitamins, minerals, and antioxidants. It's a win-win.
What does not make your gut happy is the typical American meal plan—low in fiber and high in saturated fats. In research performed on mice, scientists found that switching what they ate from a nutrient dense, high fiber diet to a low fiber, high fat diet dramatically changed the type bacteria that flourished in the intestine. "The gut is always precariously balanced between trying to contain these organisms and not to overreact," said Eric C. Martens, a microbiologist at the University of Michigan explained to the New York Times. "It could be a tipping point between health and disease."
Fiber also increases the diversity of bacteria in the digestive tract. The Mayo Clinic has a useful chart of the highest fiber foods here. Hint: eat more raspberries and lentils and fewer slices of white bread.
The bottom line is if you are in relatively good health and eat a fiber-rich diet along with some fermented foods and get outdoors and interact with nature, you'll keep your gut bacteria happy. Not sexy, but sensible.