Some of the most fascinating nutritional research to emerge in recent years has to do with the teeny, tiny microbes that live inside our digestive tract, from the tip of your lips to the, well, the other end.
We’ve long known that we’re all infested with bacteria, yeasts, fungi and other hangers-on, some of which, like E. coli and salmonella, can make you sick. But it’s not until recently that we’ve discovered just how vital these microbugs are to keeping things running smoothly, from helping you digest food, to educating your immune system to preventing disease.
For me, one of the most surprising aspects is that we walk around with all these microbes without even realizing it. Scientists estimate the number at 100 trillion (100,000,000,000,000 for those who prefer numerals). That’s 10 times more than the number of cells that make up what we traditionally call the human body.
In other words, about 9/10 of what you consider to be you is, actually, not you.
While these human microbiota, as the collection of bugs is called, are vital to health, if the ecosystem gets out of balance — due to illness, antibiotics or poor diet — it can lead to problems ranging from gastrointestinal disorders and allergies to autoimmune diseases and even, perhaps, obesity.
So it makes sense that you want to do whatever you can to keep those bugs healthy, happy and humming along. To find out how, I called Rob Knight, professor of the Microbiome Initiative at the University of California, San Diego. He’s also author, with Brendan Butler, of the recently published “Follow Your Gut: The Enormous Impact of Tiny Microbes” (Simon & Schuster, $16.99). The book expands on a TED Talk that Knight gave in Vancouver in 2014.
“A lot of what you can do to keep your microbiota healthy are things you should already be doing,” Knight said.
This includes eating lots of soluble fiber, sometimes referred to as prebiotics (not to be confused with the more familiar probiotics). Prebiotics cannot be digested by humans but instead provide nutrients to the beneficial microbe species in the gut. You’ll get a variety of prebiotics by eating a wide array of colorful fruits and vegetables, including leafy greens, tomatoes, carrots and blueberries.
For years yogurt companies have sold their products based on the promise that they contain active cultures like those naturally found in the gut and that they promote “digestive health,” “immunity,” “wellness” or other vague benefits that don’t have to be approved by the Food and Drug Administration.
There is, in fact, evidence that yogurt does these things. But Knight notes that the bacterial strains in yogurt were selected because they will not colonize the gut. In other words, you have to keep buying the yogurt to continue enjoying the benefits. Sneaky, eh?
He also called “plausible” a theory I’d heard elsewhere that it’s better to eat whole grain rather than whole wheat bread. That’s because in whole grain bread the wheat kernel remains intact; it hasn’t been pulverized to make whole wheat flour. Since an intact wheat kernel takes longer to digest, it travels further down the intestine, where more of the good gut bacteria vital to health live.
Finally, there are the probiotic supplements sold in health foods stores and, increasingly, supermarkets. Most claim to contain millions, even billions of live microorganisms such as bifidobacterium and lactobacillus to hazily “fortify,” “build” and “support” the digestive system and even your overall well being.
The problem, Knight explained, is there’s been plenty of hype about probiotics but relatively little research.
It’s hard, for example, to tell which species and strain of bacteria, and at what dose, is best. That’s because there’s no comprehensive, authoritative, easy-to-read source to learn which probiotic you need for whatever condition needs addressing. Your best bet, according to Knight, is PubMed, the online search engine of medical studies. But then you’ll need to know how to read and interpret dense scientific verbiage. I’ve been doing it for 25-plus years and believe me, it’s not easy.
rmarini@express-news.net
Twitter: @RichardMarini
Building a better microbiome
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