We’ve relied on antibiotics to save lives for nearly a century, but even short courses can thin the “good bugs” that help with digestion, immune function, and mood. If you’ve had a course of antibiotics recently, repairing and rebuilding the gut microbiome begins with small, steady habits. With fibre‑rich foods, a gentle rotation of fermented favourites, and daily rhythms, the microbiome can regain stability that serves your whole body as it ages.
Meet your microbiome
A balanced gut microbiome helps break down fibres into short‑chain fatty acids that fuel the colon lining, support immune training, and send signals along the gut-brain axis.
Gastroenterologist Paul Feuerstadt, MD, explains that certain antibiotics can reduce levels of Bacteroidetes and Firmicutes, two key beneficial bacterial phyla. After a course of antibiotics, especially in older adults, a thinner, less diverse baseline can mean larger and longer-lasting shifts in gut bacteria and their metabolites. This can slow recovery, unsettle digestion, and raise the chance of infection.
“A main risk for Clostridium difficile [C. diff] is recent antibiotic use,” says Feuerstadt about the intestinal infection that includes symptoms such as diarrhea and colitis. These impacts from antibiotic use make a simple recovery plan worth prioritizing after treatment.
Supplements to restore your gut microbiome during and after antibiotics
- Probiotics: Choose products with Lactobacillus and Bifidobacterium to prevent antibiotic-associated diarrhea.
- Prebiotics: Substances such as partially hydrolyzed guar gum, galacto-oligosaccharides, and inulin are prebiotic fibres that serve as “food” for beneficial gut bacteria.
- Postbiotics: Heat-killed (inactive) postbiotic bacteria can help strengthen the gut lining and promote antimicrobial activity against gut pathogens.
- L‑glutamine: A fuel for intestinal cells, L-glutamine has been shown to restore intestinal barrier function.
- Digestive enzymes: When combined with probiotics, these substances have been shown to help restore microbial diversity.
- Garlic: Garlic may promote beneficial bacteria and short-chain fatty acid production.
Food‑first recovery
Focusing on food is a natural and practical way to rebuild your gut microbiome. The American Gut Project found people who eat about 30 different plant foods per week tended to have more diverse microbiomes than those who consumed 10 or fewer. Aim for 20 to start, then build toward 25 to 30 as your digestive tolerance improves.
Settle and support the survivors
“Support the microbiome that survived the antibiotics for at least a week,” says microbiome scientist Momo Vuyisich. He suggests starting with soft, simple meals if your digestion feels off, such as stews, cooked vegetables, oats, rice, or blended bean soups. Consuming three evenly spaced meals daily in slightly lighter portions than you normally would is “probably the best approach to being gentle on your recovering microbiome,” he says.
Fermented favourites: the teaspoon approach
Rotate intake of small portions of fermented foods—such as yogurt, kefir, sauerkraut, kimchi, miso, or tempeh—beginning with single teaspoons, then building to small daily servings as tolerated. Fermented foods have been shown to increase microbial diversity and may improve gastrointestinal outcomes.
Increase fibre slowly without the bloat
“Slowly work in any prebiotic- and probiotic-rich foods and supplements,” says Vuyisich. Favour soluble-fibre-rich picks such as oats, barley, chia, psyllium, and cooked root vegetables.
Colour for compounds your microbes love
Aim for berries, dark leafy greens, olives, herbs, tea, cocoa, and other polyphenol‑rich choices. Microbes in the colon transform these compounds into bioactive forms and, in turn, promote beneficial microbiome shifts.
Combine protein with fibre
Pair easy‑to‑chew proteins (such as eggs, yogurt, tofu, fish, and tender legumes) with fibre at meals to provide the building blocks for tissue repair and immune function without overburdening a sensitive digestive system.
Once you’ve completed your course of antibiotics, make lifestyle changes slowly and with consistency. Build meals around fibre; add small daily servings of fermented foods; and develop simple routines for sleep, movement, and stress management. Over a few weeks, these habits help your microbiome find its balance again. If symptoms linger or worsen, check with your healthcare practitioner.
Microbiome reset: the 20- to 30-plant week
Aim for 20 to 30 different plants per week to feed more “good bugs.” According to the American Gut Project, a wide range of foods count, not just fruits and vegetables. Consider consuming:
- Legumes: chickpeas, lentils, and beans
- Mushrooms: any variety
- Alliums and prebiotics: garlic, onions, leeks, asparagus, Jerusalem artichokes, and green bananas
- Soluble fibre: oats, barley, psyllium, chia, and cooked root vegetables
- Resistant starch: cooled potatoes or rice
- Fermented foods (1 tsp to start): yogurt, kefir, sauerkraut, kimchi, miso, or tempeh
This article was originally published in the March 2026 issue of alive magazine.
