Fermented foods with and without live microbes
| Food | Live microbes? | What to look for |
|---|---|---|
| Yogurt and kefir | Often | "Live and active cultures" on the label |
| Sauerkraut and kimchi | When fresh or refrigerated | Refrigerated, not shelf-stable or heat-treated |
| Miso and tempeh | Can contain them | Processing and heat can kill live microbes |
| Kombucha | Can contain them | Check the label for live cultures |
| Pickles | Only fermented kinds that aren't heat-treated | Refrigerated and labeled fermented or with live cultures |
| Cheese and cottage cheese | Many cheeses | "Live cultures" on the label |
| Sourdough bread | No | Baking kills the microbes |
| Soy sauce and heat-treated vegetables | No | Processing kills the microbes |
Probiotic foods vs supplements
A probiotic, by definition, is a live microorganism shown to give a health benefit in adequate amounts. Few microbes in fermented foods have been named and tested that way, so most fermented foods aren't probiotics in the strict sense, even though they contain live microbes.
- Foods: a range of microbes plus nutrients; fermentation can also raise some vitamins and improve digestibility and shelf life. Amounts of live microbes vary and are usually lower than in supplements.
- Supplements: specific, named strains at a stated amount, useful when you want a strain studied for a particular purpose, such as diarrhea during antibiotics.
- Both: effects depend on the strain, and neither replaces medical care.
What research shows about fermented foods
In a 2021 Stanford study, 36 healthy adults ate either a high-fermented-food or high-fiber diet for 10 weeks. The fermented-food group had higher gut microbial diversity and lower levels of 19 inflammatory proteins, including interleukin-6. The fiber group didn't see those changes over the same period.
The researchers called it a proof of concept: it was small, short, and in healthy people. ISAPP says fermented foods may support the immune system and lower the risk of some diet-related metabolic diseases, and that scientists are still working out the benefits of specific foods.
Adding fermented foods
- Start with small portions and build up, especially if you have a sensitive gut.
- Pair them with fiber-rich foods such as beans, whole grains, onions, garlic and asparagus, which feed your gut microbes. See prebiotic vs probiotic.
- Watch added sugar in flavored yogurts and kombucha, and salt in sauerkraut, kimchi and miso.
If you have a weakened immune system, ask a clinician before starting probiotic supplements. A free Gabriel account pays cost-plus prices on supplements, and Gabriel Core and Plus member prices are lower still.
Common questions
What foods are high in probiotics?
Yogurt and kefir with live and active cultures, refrigerated sauerkraut and kimchi, miso, kombucha and many cheeses contain live microbes.
Are all fermented foods probiotic?
No. Baking, pasteurizing and heat treatment kill the microbes in foods such as sourdough bread and soy sauce, and most food microbes haven't been tested as probiotics.
Is sauerkraut a probiotic?
Fresh, refrigerated sauerkraut made with live cultures contains live microbes. Shelf-stable, heat-treated sauerkraut doesn't.
Are probiotic foods better than supplements?
They do different jobs. Foods add a mix of microbes and nutrients; supplements give specific strains studied for particular uses.
How do I know if a food has live cultures?
Look for "contains live cultures" or "live and active cultures" on the label, or ask the manufacturer.
Sources
- What are fermented foods? International Scientific Association for Probiotics and Prebiotics
- Fermented foods International Scientific Association for Probiotics and Prebiotics
- Probiotics Cleveland Clinic
- The Microbiome The Nutrition Source, Harvard T.H. Chan School of Public Health
- Fermented-food diet increases microbiome diversity, decreases inflammatory proteins, study finds Stanford Medicine
This guide is general information, not medical advice. It does not replace a visit with a licensed clinician. Gabriel membership is not health insurance.