Many common foods naturally contain prebiotics, probiotics, or both. Probiotics are live microorganisms found in fermented foods like yogurt, kefir, kimchi, and sauerkraut. Prebiotics are types of fiber that feed beneficial gut bacteria, and they’re found in foods like garlic, onions, bananas, and oats. Eating both together gives your gut the beneficial bacteria it needs along with the fuel to keep them thriving.
How Prebiotics and Probiotics Work Together
Probiotics introduce live bacteria into your digestive system. Prebiotics are the food those bacteria eat. When you combine both in the same meal or the same day, you create what researchers call a “synbiotic” effect, where the prebiotic fiber specifically supports the growth of the probiotic bacteria. For example, certain plant-based fibers called fructans are particularly good at fueling probiotic lactic acid bacteria and stimulating their growth.
This pairing appears to be more effective than either one alone. In a clinical trial comparing probiotic-only, prebiotic-only, and combined synbiotic therapy in people with ulcerative colitis, the synbiotic group saw greater quality-of-life improvements and a significant drop in inflammatory markers compared to either treatment on its own. Another study found that pairing a probiotic with the prebiotic fiber inulin improved the effectiveness of standard treatment for H. pylori stomach infections.
Foods That Contain Probiotics
Probiotic foods are fermented by live bacteria or yeast that remain active in the final product. The key word here is “live.” Not every fermented food qualifies as a true probiotic. The International Scientific Association for Probiotics and Prebiotics defines a probiotic as a live microorganism that, when consumed in adequate amounts, provides a documented health benefit. The bacteria need to be identified down to the strain level and present in sufficient numbers through the product’s expiration date.
That said, many fermented foods contain beneficial live cultures even if they haven’t been formally tested as probiotics. Here are the most widely available options:
- Yogurt contains Lactobacillus and Streptococcus thermophilus as its primary cultures. Look for labels that say “live and active cultures,” since some yogurts are heat-treated after fermentation, which kills the bacteria.
- Kefir is one of the most microbiologically diverse fermented foods. A single batch can contain dozens of bacterial species, including multiple Lactobacillus strains, Lactococcus, Leuconostoc, and beneficial yeasts. It typically has a broader range of microbes than yogurt.
- Sauerkraut (unpasteurized) is fermented cabbage that develops Lactobacillus and Leuconostoc bacteria during the curing process. It must be raw and refrigerated to contain live cultures. Shelf-stable versions sold in jars at room temperature have been pasteurized.
- Kimchi is a Korean fermented vegetable dish that harbors Lactobacillus, Leuconostoc, and Weissella bacteria. Like sauerkraut, it needs to be unpasteurized to deliver live microbes.
- Miso is a fermented soybean paste used in Japanese cooking. Adding it to boiling water destroys much of the live culture, so stirring it into warm (not boiling) soup helps preserve more bacteria.
- Tempeh is made from fermented soybeans bound together by a beneficial mold. It provides a different type of fermentation than dairy-based probiotics.
- Kombucha is a fermented tea that contains a mix of bacteria and yeast. Sugar content varies widely between brands.
Foods That Contain Prebiotics
Prebiotic fiber isn’t digested in your stomach or small intestine. Instead, it travels to your colon where beneficial bacteria ferment it, producing short-chain fatty acids like butyrate that nourish your gut lining. Certain types of oligosaccharides can specifically increase butyrate-producing bacteria in the intestine.
The richest sources of prebiotic fiber include:
- Garlic and onions are among the most concentrated sources of fructans, a key prebiotic fiber. Raw forms contain more prebiotic content than cooked, though cooking doesn’t eliminate it entirely.
- Leeks and asparagus also contain high levels of fructans and inulin.
- Bananas provide prebiotics, especially when slightly underripe. Green bananas contain more resistant starch, which acts as a prebiotic.
- Oats contain beta-glucan fiber that feeds gut bacteria.
- Jerusalem artichokes (sunchokes) are one of the highest natural sources of inulin.
- Chicory root is so rich in inulin that it’s used to manufacture prebiotic supplements. You’ll find it as an ingredient in many high-fiber bars and cereals.
- Legumes like lentils, chickpeas, and beans contain galacto-oligosaccharides (GOS), another type of prebiotic fiber.
- Wheat bran provides prebiotic fiber along with other types of dietary fiber.
Prebiotic Options for Sensitive Stomachs
Many of the best prebiotic foods, like garlic, onions, and wheat, are also high in FODMAPs, the short-chain carbohydrates that trigger bloating and discomfort in people with irritable bowel syndrome. That’s not a coincidence: fructans and galacto-oligosaccharides are both prebiotic fibers and FODMAPs.
If you follow a low-FODMAP diet, you can still get prebiotics from carefully portioned foods. According to Monash University, which developed the low-FODMAP diet, these foods have prebiotic benefits at serving sizes that stay within safe FODMAP limits:
- Canned, rinsed chickpeas and lentils (the canning and rinsing process reduces FODMAP content)
- Beetroot and butternut pumpkin
- Oats and buckwheat
- Almonds and hazelnuts (about 10 nuts per serving)
- Pomegranate seeds (a quarter cup)
- Cooked and cooled wheat or spelt pasta (cooling increases resistant starch, which acts as a prebiotic, while also lowering the FODMAP content)
How Cooking and Storage Affect These Foods
Prebiotics and probiotics respond very differently to heat. Prebiotic fiber is stable through most cooking methods. You can roast garlic, sauté onions, or bake with oats without destroying their prebiotic content. The fiber structure survives normal kitchen temperatures.
Probiotics are a different story. Live bacteria are fragile. Heating to 60°C (140°F) for just 15 minutes kills roughly 95% of viable cells. Temperatures above 80°C (176°F), which includes blanching, boiling, canning, and stir-frying, will destroy essentially all probiotic bacteria. Some strains are hardier than others: Lactobacillus species survive heat significantly better than Bifidobacterium species, but none can withstand actual cooking temperatures.
This has practical implications for your kitchen. If you’re making miso soup, add the miso paste after taking the pot off the heat. Eat sauerkraut and kimchi raw or add them as a topping after cooking. Choose unpasteurized, refrigerated versions of fermented vegetables rather than shelf-stable ones. Yogurt and kefir should be eaten cold or at room temperature.
Acidic environments also reduce heat tolerance in probiotic bacteria. Bacteria suspended in acidic conditions (like a fermented food with a low pH) die faster when exposed to heat than the same bacteria in a neutral environment. So adding yogurt to a hot, acidic tomato sauce is particularly destructive to its live cultures.
Simple Ways to Combine Both
You don’t need to eat prebiotics and probiotics at the exact same time, but pairing them in the same meal is a straightforward way to get both. Some practical combinations:
- Yogurt or kefir with banana and oats: the dairy provides probiotics while the banana and oats supply prebiotic fiber.
- Kimchi or sauerkraut over a grain bowl with legumes: fermented vegetables for probiotics, beans or lentils for prebiotic GOS fiber.
- Tempeh stir-fry with asparagus and garlic: the tempeh is fermented (though cooking will reduce live cultures), and the vegetables provide fructan-type prebiotics.
- Smoothie with kefir, underripe banana, and oats: keeps the kefir unheated and pairs it with two prebiotic sources.
The simplest approach is to eat a variety of fermented foods regularly while also eating plenty of vegetables, whole grains, and legumes. Diversity in your diet tends to produce diversity in your gut microbiome, and that diversity is consistently linked to better digestive health.