Fermented and probiotic foods contain living colonies of potentially beneficial microorganisms. When consumed, they can boost the health of your gut microbiome, the community of trillions of cells living in your body that plays a massive role in your digestive health. The right mix of bacteria, fungi, and other tiny organisms has the potential to improve your metabolism and your diabetes management.
“The gut microbiome plays a role with insulin sensitivity and the breakdown of glucose, which will affect diabetes management,” says Toby Smithson, RDN, CDCES, the author of Diabetes Meal Planning & Nutrition for Dummies.
Probiotics from food (and supplements) only survive in the GI tract for several days, so you need to consume them regularly to reap the benefits.
Is There an Ideal Type 2 Diabetes Diet?
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What Are Fermented and Probiotic Foods?
Fermented foods have undergone a process of fermentation: Microorganisms transform the food by breaking down carbohydrates, including sugars. This activity can enhance the flavor of food, and it also results in the creation of beneficial bacteria known as probiotics.
“Certain foods naturally contain healthy bacteria, which helps support a healthy microbiome,” says Amy Kimberlain, RDN, CDCES, a Miami-based spokesperson for the Academy of Nutrition and Dietetics.
In addition, probiotics are sometimes used to fortify foods that aren’t fermented. You can find probiotics in:
Not all fermented foods contain probiotics, says Kimberlain. “Only those with live, active cultures survive digestion and provide a benefit,” she says. Sourdough bread, for example, requires fermentation for the dough to rise and develop flavor, but microorganisms do not survive the baking process. You’ll need to read product labels to be sure the one you buy contains what you need.
Probiotics and Diabetes
If you have diabetes, probiotic and fermented foods may be a wise addition to your eating plan. A healthy microbiome can help boost your immune system and fight off inflammation, which plays a significant role in the development and progression of diabetes.
“Emerging research shows that people with type 2 diabetes often have imbalances in their gut microbiome, which may contribute to inflammation, insulin resistance, and blood sugar dysregulation,” says Kimberlain.
Supplementing with probiotics and prebiotics (plant fibers that feed probiotics) has been shown to reduce inflammation and improve insulin resistance, which could help lower your blood sugar and ease your diabetes management. But it’s not considered a treatment for diabetes just yet: One review noted that the gut changes from fermented and probiotic foods aren’t large enough to recommend using it as treatment for diabetes, nor is probiotic supplementation a substitute for diabetes medication. But that doesn’t mean they don’t have value in your diet.
“While not a standalone treatment, these foods can complement a balanced diet, medications, and other lifestyle changes in diabetes care,” says Kimberlain.
There is also a lot of research on individual fermented and probiotic foods showing similarly encouraging results. But some of those positive results may be because these foods are nutritionally sound rather than any probiotic activity.
Yogurt
One study of 72 people with type 2 diabetes found that consuming 200 grams (g) of probiotic yogurt per day (less than 1 cup) for 12 weeks led to a reduction in A1C levels, total cholesterol, and LDL cholesterol compared with placebo.
That said, not all research on the health benefits of probiotics in yogurt is consistent. An earlier meta-analysis on the effect of probiotic yogurt on glucose control found no benefits when the study authors compared probiotic yogurt with conventional yogurt’s ability to improve glucose control in patients with diabetes or obesity.
But beyond the probiotic potential, yogurt — especially Greek and skyr types — is rich in protein, which helps slow down digestion of the carbohydrate in yogurt, says Smithson. Kimberlain says people with diabetes should opt for varieties that are plain or unsweetened, and add sweetness with fresh fruit, cinnamon, and vanilla extract.
Kimchi
Kimchi is a traditional Korean dish made from fermented vegetables, often cabbage and radishes. One study found that people with prediabetes had improvements in their A1C levels, fasting insulin, and insulin resistance after eating kimchi for two sets of eight weeks. Beyond the improved insulin benefits, the study also found that kimchi lowered cholesterol and body fat, which can help address metabolic syndrome, a significant risk factor for type 2 diabetes.
Sauerkraut and Pickles
Alongside kimchi, sauerkraut and pickles are other nonstarchy options for a diabetes-friendly menu, says Smithson. She provides a few caveats: Both can be high in sodium, so balance your plate out with healthy veggies like broccoli and cauliflower when you eat them.
And not all sauerkraut and pickles have probiotics. If you want some that do, look for those that are jarred in the refrigerated section and check the label for words like “fermented with cultures.”
Kombucha
Kombucha is a fermented, fizzy drink made with tea, sugar, and bacteria, and yeast. One small study found this beverage lowered average fasting blood glucose levels in people with diabetes after drinking 8 ounces (oz) a day with dinner for four weeks.
Kombucha is naturally sour, so it can be flavored with juices, added sugars, or sugar substitutes to make it more palatable. Kimberlain says to make sure you choose a brand (or make your own) that aligns with your diabetes diet goals. When you’re reading labels, also consider how much sugar is in the entire bottle or can, since some contain more than one serving.
Tempeh
Tempeh is made from fermented soybeans, and you can purchase it packaged in the refrigerated section of your grocery store near the tofu. One animal study found that when tempeh was a part of a regular diet it improved both blood glucose and body weight.
Tempeh is diabetes-friendly in other ways, too. Kimberlain points out it’s naturally low in carbs. A 3.5 oz serving has 195 calories and less than 8 g of carbohydrates. Use it as a plant-based meat substitute in meals like stir-fries, or baked and tossed onto a salad. Like tofu, it can take on whatever flavors from spices or marinades you add to it.
Probiotic Supplements
Since some people don’t enjoy the taste of fermented foods, probiotic supplements can be a viable option to boost your health. Probiotics are unlikely to cause harm in healthy people, and the side effects are usually minor. Supplements can come in the form of capsules and tables, gummies, liquids, and powders, and they contain one to many different types of bacterial strains. They may, however, be less beneficial than the probiotics that are found naturally in food sources.
Smithson says she prefers a food-first approach for digestive health. Supplements are not regulated by the U.S. Food and Drug Administration (FDA), so talk to your healthcare provider before taking them. Kimberlain suggests discussing these topics:
Could probiotic supplements interact with any medications I take?
What strains should I be looking for with a supplement? “Each strain has different health benefits,” she says.
What dose should I be taking?
The Takeaway
Fermented foods and other nutritional sources of probiotics can improve the health of your microbiome and may help ease your diabetes management. They can also help lower inflammation and help you lose weight.
Fermented foods and probiotics include certain types of yogurt, kefir, and other dairy products; sauerkraut, kimchi and pickles; kombucha, and certain soy products. Probiotics are also available in nutritional supplements.
Fermented and probiotic foods are not currently a substitute for diabetes medications, but they can be a part of a healthy diabetes diet.
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
Li W et al. Gut Microbiota and Diabetes: From Correlation to Causality and Mechanism. World Journal of Diabetes. July 15, 2020.
Weinberg Sibony R et al. Overview of Oxidative Stress and Inflammation in Diabetes. Journal of Diabetes. October 22, 2024.
Sadagopan A et al. Understanding the Role of the Gut Microbiome in Diabetes and Therapeutics Targeting Leaky Gut: A Systematic Review. Cureus. July 8, 2023.
de Almeida Souza C et al. Traditional Fermented Foods as an Adjuvant Treatment to Diabetes. Current Geriatrics Reports. November 11, 2020.
Mirjalili M et al. Effect Of Probiotic Yogurt Consumption on Glycemic Control and Lipid Profile In Patients With Type 2 Diabetes Mellitus: A Randomized Controlled Trial. Clinical Nutrition ESPEN. April 2023.
Barengolts E et al. The Effect of Probiotic Yogurt on Glycemic Control in Type 2 Diabetes or Obesity: A Meta-Analysis of Nine Randomized Controlled Trials. Nutrients. March 20, 2019.
What Is Kombucha Tea? Mayo Clinic. September 26, 2024.
Mendelson C et al. Kombucha Tea as an Anti-Hyperglycemic Agent in Humans With Diabetes: A Randomized Controlled Pilot Investigation. Frontiers in Nutrition. August 1, 2023.
Su H et al. The Effects of Using Tempeh as a Supplement for Type 2 Diabetes. Food Science & Nutrition. March 17, 2023.
Kara Andrew, RDN, LDN, is the director of health promotion for Memorial Hospital in Carthage, Illinois. She is also licensed as an exercise physiologist and certified in lifestyle medicine by the American College of Lifestyle Medicine. Her experience includes corporate wellness, teaching for the American College of Sports Medicine, sports nutrition, weight management, integrative medicine, oncology support, and dialysis.
She earned her master's in exercise and nutrition science at Lipscomb University.
Andrew has served as a president and board member of the Nashville Academy of Nutrition and Dietetics. She was recently elected a co-chair of the fitness and medicine group in the American College of Lifestyle Medicine.
Jessica Migala is a freelance writer with over 15 years of experience, specializing in health, nutrition, fitness, and beauty. She has written extensively about vision care, diabetes, dermatology, gastrointestinal health, cardiovascular health, cancer, pregnancy, and gynecology. She was previously an assistant editor at Prevention where she wrote monthly science-based beauty news items and feature stories.
She has contributed to more than 40 print and digital publications, including Cosmopolitan, O:The Oprah Magazine, Real Simple, Woman’s Day, Women’s Health, Fitness, Family Circle, Health, Prevention, Self, VICE, and more. Migala lives in the Chicago suburbs with her husband, two young boys, rescue beagle, and 15 fish. When not reporting, she likes running, bike rides, and a glass of wine (in moderation, of course).
