Monday, February 28, 2011

Honor Thy Gut (Marin IJ)

The human intestines (the gut) are like something out of a sci-fi movie, a world inside a world with much more intrigue than you might expect. Your gut, comprised of two dozen or so feet of twisting peristaltic tubes, has a mind of its own – looping, gurgling and diffusing its way to digestion. Slow and steady like a caterpillar on the move, the bowel functions in anonymity, until something goes wrong.

Deep in the bowel you’ll find a stew of microorganisms that make the breakdown of food and absorption of nutrients possible. Scientists know this crock-pot of little critters as a mircrobiome and it consists of millions of densely packed bacteria and yeasts, with names like Lactobacillus, Bifidobacterium, and Saccaromyces. In sum, these body microbes outnumber human cells by ten to one! Constantly at work, the gut microbiome serves many crucial functions; it turns food products into usable energy forms such as sugars and short chain fatty acids, it produces vitamins such as Vitamin K and biotin, and it protects against disease in a number of ways. And while we’ve known for some time that microbes play a critical role in the gastrointestinal tract, we are just beginning to appreciate the magnitude of their influence and the uniqueness of their composition on a person-to-person basis. That’s right, your microbiome is unique to you – it’s your own living micro-signature.

So, you may be wondering what you can do to cultivate a healthy microbiome? Recently, I spoke with Lita Proctor, Ph. D, Coordinator of the Human Microbiome Project – a National Institutes of Health (NIH) funded endeavor to catalogue the microbe communities of the human body using sophisticated DNA analysis. The following tidbits of advice are based on her thoughts as well as a sampling of the available scientific evidence.

*You and your microbes will have many more good times than bad. For every microbe-induced sore throat or upset tummy, there will be thousands upon thousands of illnesses that your personalized microbes will shield you from.

*Pro-biotics (live microbes found in products such as Culturelle and Align) do work – some of the time, for some conditions. But we don’t know exactly why. Someday, your medical record may include a full tracing of your genome and microbiome – allowing us to predict and prevent common nuisances (such as antibiotic-associated diarrhea). But until then, consider pro-biotics in certain situations (such when you’re dealing with antibiotic-associated diarrhea) but do so with some caution. Newborns (who begin sterile but start to assemble their own microbiome as they pass through the birth canal) and people with compromised immune function probably should not routinely be supplemented with excess microbes. For more information on pro-biotics, check out the National Center for Complimentary and Alternative Medicine at

*Pay attention to pre-biotics. No, that’s not a typo. Pre-biotics as the name suggests, are like the precursors of pro-biotics. These nondigestable food ingredients, called oligosaccharides, stimulate the growth and activity of the gut microbiome. They are found in many vegetables as well as in bananas, oats and soybeans. In a recent Italian study, adding pre-biotics to re-hydration fluid for children with diarrhea significantly reduced the severity and duration of symptoms (compared to standard re-hydration fluids). The NIH is actively investigating both pro-biotics and pre-biotics, in fact they have assembled a working group tasked with identifying “gaps and challenges in pre-biotic and pro-biotic research.”

*Keep your calories down. One proposed explanation for our obesity epidemic is that obese people have, over time, preferentially selected (via natural selection, not conscious selection) certain highly efficient gut bacteria. These bacteria are much better at extracting energy from food than the gut bacteria of thin people. The theory is that once you’ve cultivated these super efficient microbes in your GI tract, you’ll extract more calories from your food even when you eat significantly less of it. Perhaps someday there will be an antibiotic for obesity, but in the meantime, best not to overeat. By the way, another in-vogue hypothesis is that a nutrionally-balanced low calorie diet can extend your life span. Animal studies and some preliminary cardiovascular-based studies seem to support this contention. So, live little rather than go big and you might just stick around longer.

*When it comes to cleansing, moderation is key. Don’t go crazy de-toxing, bleaching, and germaphobing. Gut cleansers and unnecessary antibiotic users – this means you. Heard this before? Well’s it’s called the hygiene hypothesis; the contention that modern society, like the town pastor in Footloose, protects us too forcefully from the unclean, depriving our immune system from useful practice and our microbiome from helpful stimulation. So, when you are sick or in the hospital, be sure to strictly follow hygiene standards, but otherwise remember, “Gaia made dirt, and dirt don’t hurt.”

Of course infectious diseases are still major killers and interventions like vaccinations and antibiotics undoubtedly save millions of lives. But let’s take time to celebrate the good little guys, too. Let’s thank the microbes that ferment grapes and hops, produce yogurt and cheese, and raise lofty loaves of bread. And let’s be proud of our personalized squadrons of sustenance-processing magicians and give them a helping hand every once in a while. If you find yourself in a digestive rut, go ahead and cultivate that gut!