Page 51 - EatingWell Special Edition Superfoods 2019

Y O U R H E A L T H I E S T M E A L T I M E

The fire pit is his kitchen. He has an open-air raw food, paleo and others. He followed each
shower, and the toilet is in a doorless shed. Only one for 10 to 12 days, collecting daily stool sam-
one 7-by-12-foot room is closed to the elements; ples. His first trial was a high-fat (70% of cal-
it includes a single cot, a desk, a laptop comput- ories), average-protein (25%) diet with little
ers, leaning towers of research papers and…a few carbohydrates and near zero dietary fiber. This
dozen poison-tipped arrows (we’ll get to those diet, he explains, starved his microbes of food.

soon). Out here, Leach is reconnecting with his Proteobacteria, practically nonexistent before,
microbes because he knows how critical they are. increased.
Most of our resident gut bacteria are real work- “This group includes a lot of your bad
horses. Some aid in digestion and produce en- guys— E. coli, salmonella. They are associated with
zymes to break down foods. Others make vita- inflammation and may increase your risk of dis-
mins, like B12 and K, and other vital compounds, ease.” At the same time, numbers of actinobacte-
such as the feel-good chemical serotonin. A few ria, typically considered good guys and known to

help keep the intestinal lining impenetrable. Some suppress proteobacteria, dropped.
gut bacteria help regulate metabolism. And others He’s since done several variations of this diet—
boost immunity and fight pathogens. adjusting fat, carbs, protein and fiber. “It’s the
Of course, not all bacteria are beneficial. Some fiber that’s the game changer,” Leach says. Add-
amplify inflammation or cause life-threatening in- ing 40 to 60 grams of fiber per day seems to shift
fections. But we carry them all naturally; they cre- his gut microbiome toward a
ate problems only when the microbial balance be- diverse, more beneficial mix
comes disturbed. of microbes. Over time,
There are many ways our microbiome can get Here’s why: like all living eating a low-

off-kilter and make us prone to infections or dis- things, bacteria need food fiber diet can
ease. For example, taking antibiotics shifts the to survive. They do that by weaken digestive
balance of microbes in our gut. As a result, the fermenting—that’s the way defenses,
infectious dose of salmonella for someone on these guys “eat”—dietary allowing bits
an antibiotic is just one-thousandth the amount fiber. But gut bacteria are of dead bacteria
that’s needed to infect someone who’s not taking picky. Only certain types of to get into the

antibiotics. Diet is another way we can tip the bal- fiber will do—and most of us bloodstream.
ance unfavorably. don’t eat enough of the kind
that bacteria need.
Essential Fuel for Your Microbiome Fibers are like pearl necklaces of varying bead-
“We should start thinking about diets from the length. Most fibers we eat are so short, they get
perspective of what we should be feeding our gut chomped long before they make it to where bac-
microbes,” says Leach. “Nothing matters more.” teria are concentrated, the beginning of the large
A seminal study published in Nature in 2013 intestine, aka the colon.
compared the gut microbiome of people eating Two fiber types long enough to survive the

an entirely animal-based diet (meats, cheeses and length of our gastrointestinal (GI) tract are fruc-
eggs) with one that was completely plant-based tan and cellulose fibers—part of a group of foods
(grains, legumes, vegetables and fruits). Just one known as prebiotics, foods that encourage the
day on either diet was enough to dramatically growth of good bacteria. Cellulose fibers are in
shift the gut microbiome of participants. While the tough parts of veggies and fruit we tend to
researchers knew that diet could cause changes toss—like the stalks of broccoli and bottoms of
to the gut microbiome, this was the first study to asparagus—and the stringy bits of celery. Fructan

show such a rapid effect in people. fibers are found in many fruits and vegetables—
Leach has done similar, informal tests on him- from artichokes to onions.
self over the years. In January 2014, he tried a va- But how you prepare these foods also matters.
riety of different diets: fermented foods, vegan, That’s because heat breaks down fibers. Consider

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