The more I read about probiotics and the gut microbiome, the more I believe that gut health is going to determine our future understanding of human health. And not just digestive function. There’s growing evidence that gut microbes affect brain function: everything from mood to cognition to social behaviors. In terms of how that information gets put into practice, there’s good news and bad news.
Bad News First
As with all things nutrition, probiotics are going to be used to market stuff to unsuspecting consumers.
- Supplements: We’ve already got probiotic supplements, handy capsules of bacteria designed to boost so-called good bacteria. Problem is, there’s not a lot of solid evidence that more of some particular strain of bacteria, given in a gelatin capsule, will do much good. Are the bacteria viable (they’ll actually survive in your gut)? Are you eating foods this particular bacteria will thrive on? Do you actually benefit from this bacteria? What about all the other thousands of potentially healthy bacteria not included in your supplement? “Probiotic” does not refer to one thing, the way ‘vitamin B1’ refers to a single molecule. And keep in mind: supplements are not regulated. They just have to be ‘safe’. No one has to demonstrate that they’re effective.
- Fortified Food Products: Probiotics are going to start showing up in strange places. Cereal? Energy drinks? Pop Tarts? Don’t laugh! It’s not hard to imagine junk food pimped up with a dusting of probiotics, just so the label can scream “Contains probiotics!!!” This kind of sales pitch could easily appeal to people who don’t understand that probiotics are living organisms and might not survive in ice cream or a soy latte. And of course, we get back to the question of which probiotic? There are thousands of potential beneficial bacteria. Which one was sprinkled in that smoothie?
And here’s the ultimate problem with this approach to gut health: people will think “I took the supplement/ate the cereal, therefore I’ve got gut health”. While continuing to eat a processed junky diet. The other piece of the gut health equation is this: all those different microorganisms need suitable foods in order to live in your digestive tract. And they don’t thrive on highly processed, low fiber Western diets.
Many foods are already rich in probiotics: Fermented foods have been around for centuries, and are found around the globe. When humans consume fermented foods, they ingest the yeasts and bacteria that live in those foods. You’ve probably heard of:
- kimchi (fermented cabbage and vegetables, a staple food in Korea)
- miso (fermented soy bean past, used in East Asia)
- sauerkraut (fermented cabbage, popular in central Europe)
- kefir (milk fermented with a different bacterial culture than yogurt)
- craft beers (traditional beers contain residue from the fermentation)
There are many other fermented foods that aren’t yet well known in Western countries. Have you heard of
- kumis (fermented mare’s milk consumed in Central Asia)
- kvass (a fermented drink made from rye bread, popular in Slavic countries)
- natto (fermented soybeans, popular in Japan)
One traditional fermented beverage gaining in popularity is kombucha. I recently had my first taste of this fermented tea beverage, and I’d compare the flavor to a less sweet, slightly acidic ginger beer (I sampled a ginger-flavored variety). Not bad, but probably not to the liking of Western taste buds accustomed to syrupy sweetness in everything. One of the Radio Nutrition interns is working on a post about kombucha, coming soon. She makes her own kombucha, and it’s a fascinating process using a mysterious thing called a SCOBY.
Gut health and digestion have been the focus of probiotic research for several years, but the new angle is the gut-brain connection. I watched a webinar recently about current research in this field, and there are some exciting possibilities. So far most of the research has been done on rodents, and yes, researchers have ways to assess anxiety, stress and abnormal social behaviors in mice. It turns out, germ-free mice exhibit many dysfunctional behaviors that are normalized when a healthy gut microbiome is established. For humans, there a possibility that mood disorders and symptoms of brain syndromes like autism could be improved by a healthy gut microbiome. The speaker speculated that someday we might prescribe a particular probiotic bacteria to treat certain brain diseases. Meanwhile, research on humans is nowhere near identifying which bacteria might provide which benefit. So don’t fall for any marketing hype that says a probiotic-fortified product or supplement will improve your mood.
But why wait for future research to give you a reason to include probiotic foods in your diet now? Gut health is tied to better digestion, immune function and, according to some research, may influence weight. Lots of probiotic foods such as yogurt, kefir, kombucha and sauerkraut are available in grocery stores. Kimchi is increasingly available, too. It has a very strong flavor, but some people appreciate that. You might also find smoothies or other beverages fortified with added probiotic bacteria, but again which bacteria? I prefer to go with natural sources like kefir, yogurt and kombucha.