Is Low-Fermentation Eating the Answer to SIBO?
Hypothesis and Emerging Research
Nine years ago, a C-section complication landed Krystyna Houser in the hospital with an MRSA infection and a long course of strong antibiotics. When she recovered, she didn’t quite bounce back: She found herself facing persistent bloating, brain fog, and mood swings. She spent the next two years enduring endoscopies, colonoscopies, and blood work. Even after ruling out celiac and Crohn’s disease, no doctor identified what was wrong with her or was able to help her get better. One of her doctors referred her to a psychiatrist, dismissing her symptoms as psychosomatic.
The turning point in Houser’s illness was meeting Cedars-Sinai doctors Mark Pimentel and Ali Rezaie, pioneers in gut microbiome and motility science and, as of recently, the authors of The Microbiome Connection. Pimentel and Rezaie diagnosed Houser with small intestinal bacterial overgrowth, or SIBO. As its name suggests, SIBO is defined by an imbalance of bacteria in the gut that can cause life-disrupting symptoms. Some are obviously gastrointestinal in nature—gas, bloating, diarrhea, constipation, abdominal pain—while others, like brain fog, are more difficult to pin down.
The breath test that identifies SIBO is quick, readily available, noninvasive, and inexpensive. But Houser’s previous doctors hadn’t tried it. Because SIBO shares symptoms with irritable bowel syndrome, Houser says, most doctors make an IBS diagnosis and don’t look further, even if treatments aren’t working. SIBO sufferers, on average, go six years before getting a correct diagnosis.
Once Houser’s SIBO diagnosis was confirmed, the path to remission was clear: Pimentel and Rezaie put her on an initial three-week elemental diet consisting only of a predigested nutrient formula—essentially feeding-tube liquid—to starve the bacteria in her small intestine. (Houser says it was horrible, but it kick-started her recovery.) Then they had her transition into low-fermentation eating, or LFE, a protocol they developed to dramatically reduce symptoms for long-term SIBO sufferers without the guesswork of an elimination diet.
The Basics of Low-Fermentation Eating
The goal of LFE is to limit how favorable the gut environment is to bacterial overgrowth. It consists of foods that bacteria aren’t likely to metabolize and ferment—without restricting carbohydrates entirely so that patients can maintain the protocol long-term. Ideal LFE foods include:
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Refined carbohydrates, including bagels, white or wheat bread (but not multigrain or whole wheat), pasta, egg noodles, polenta, quinoa, white rice, and corn or flour tortillas.
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Meat and eggs. Avoid legumes and soy-based meat alternatives, including tempeh and tofu.
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Noncruciferous vegetables, including arugula, kale, spinach, avocado, beets, corn, eggplant, peas, green beans, mushrooms, leeks, jicama, sweet potatoes, pumpkin, squash, and tomato.
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Fresh fruit. Shoot for one serving at a time of apricots, berries, melon, cherries, citrus, kiwi, mango, peaches, nectarines, persimmons, papaya, plums, and pomegranate. (Avoid apples, bananas, dates, pears, and figs; dried fruit is generally not well-tolerated.)
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Alt-milks and low-lactose dairy. Ghee, lactose-free milk and cottage cheese, and small amounts of butter are okay. With cheese, opt for Parmesan, aged cheddars, Manchego, and Gruyère, which are typically well-tolerated.
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Nuts and seeds, except for chia and flax.
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Most drinks, including broth, coffee, seltzer, teas, and alcohol, are okay. But avoid soda and anything with high-fructose corn syrup.
(You can find the full list of LFE-approved foods—and what foods to avoid—here.)
The long-term approach of LFE is in contrast with low-FODMAP diets—the existing standard of care for SIBO patients—which are so restrictive that doctors don’t typically recommend staying on them for more than a few weeks before working to transition off them.
Timing Meals for SIBO
Also an important factor, according to Pimentel and Rezaie: spacing meals at least four hours apart. When we allow the gut to empty out between meals, Pimentel says, our small intestine makes a physical movement to clean itself out. It pushes everything that can’t be digested into the large intestine for disposal. But if we don’t allow those cleaning waves—they only happen when the gut is empty—debris builds up in the small bowel and ferments, exacerbating bacterial overgrowth.
3 Low-Fermentation Recipes
It took a year and a half postdiagnosis for Houser to feel like herself again. She’s been flare-up-free ever since. And she credits LFE with helping to get her life back: She’s back out to restaurants and throwing dinner parties. The SIBO-friendly cookbook she cowrote with dietitian Robin Berlin, The Good LFE Cookbook, launched this past April. It’s a collection of the most delicious, comforting recipes Houser makes at home these days, like Gruyère pizza, creamy chocolate mousse, and juicy pulled pork.
Low-Fermentation Cashew Sour Cream
Low-Fermentation Mac & Cheese
Chewy Meringues & Lemon Curd
This article is for informational purposes only. It is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. To the extent that this article features the advice of physicians or medical practitioners, the views expressed are the views of the cited expert and do not necessarily represent the views of goop.
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