Probiotics and Fermented Foods: A Beginner’s Guide to Gut Health
Probiotics and fermented foods have become everyday health topics. Your gut is home to trillions of microbes that help digest food, make certain vitamins and train your immune system. Some uses of probiotics have good evidence. Many popular claims do not.
Health note: This article is for general education only. It is not medical advice and it does not replace care from your doctor. Foods and supplements are not a substitute for prescribed treatment. Talk to a licensed health professional before changing your diet, medicines or supplements, especially if you are pregnant, take prescription drugs or have a chronic condition.
- Probiotics may cut the chance of antibiotic-related diarrhea by about half in many people.
- Different strains do different things. One product’s result does not apply to another.
- Fiber from plants feeds your good bacteria, so it matters as much as any pill.
Where probiotics have evidence
Mixed evidence
- Antibiotic-associated diarrhea: a 2017 review found probiotics were linked to about half the chance of this diarrhea in people not in the hospital.
- Irritable bowel syndrome (IBS): a 2018 review of 53 studies found probiotics may help overall symptoms and belly pain, though the best strains are not yet clear.
- C. difficile infection: moderate evidence that probiotics lower risk in people taking antibiotics.
- Constipation: modest benefits, especially with Bifidobacterium strains.
Why the strain matters
Probiotics are named by genus, species and strain, for example Lactobacillus rhamnosus GG. NCCIH explains that if one kind of Lactobacillus helps a problem, that does not mean another probiotic will. Choose products that list the full strain name and have been studied for your specific goal.
Probiotics and fermented foods to try
- Yogurt and kefir with “live and active cultures” on the label
- Sauerkraut and kimchi from the refrigerated section (shelf-stable versions are usually heat-treated)
- Miso and tempeh
- Some aged cheeses
Choose unsweetened versions when you can. Many flavored yogurts have as much added sugar as dessert.
Feed your gut with fiber
Stronger evidence
Beans, lentils, oats, onions, garlic, bananas, berries and whole grains contain fiber that gut bacteria love. Most American adults eat far less fiber than recommended. Increase slowly and drink water to avoid gas.
More on energy and vitality
Gut health is one part of feeling well. Read our natural energy and vitality guide and natural sleep aids comparison.
The bottom line
The bottom line on probiotics and fermented foods: pick studied strains for specific problems, and enjoy fermented foods and fiber every day. Most healthy adults can add probiotics and fermented foods to meals with little risk.
Frequently asked questions
Should I take probiotics with antibiotics?
Some people take a studied probiotic during and after antibiotics to lower the chance of diarrhea. Separate the doses by a few hours and ask your doctor or pharmacist first.
Are refrigerated probiotics better?
Some strains need refrigeration and some are shelf stable. Follow the label and check the expiration date, because live counts drop over time.
Can I get enough probiotics from food alone?
Many people do well with fermented foods plus plenty of fiber. Supplements are most useful for specific, studied problems.
Your next step
Add one fermented food and one extra serving of beans or whole grains to your meals every day this week.
Common myths about probiotics and fermented foods
- Myth: Every probiotic works for every problem. Fact: Effects depend on the specific strain.
- Myth: All fermented foods contain live probiotics. Fact: Shelf-stable sauerkraut, sourdough bread and beer are usually heat-treated or filtered.
- Myth: More billions are always better. Fact: A higher count does not guarantee better results. Choose probiotics and fermented foods based on evidence and your goal.
Sources
About the author: Reginaldo Encarnacao is an independent health writer who researches public sources such as the National Institutes of Health (NIH). He is not a doctor, pharmacist or dietitian.
Medical disclaimer: The information on this page is for educational purposes only and is not intended to diagnose, treat, cure or prevent any disease. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. Individual results vary. See our full disclaimer.
