Last Updated: September 28, 2022

    Kefir is a probiotic fermented milk drink made with a symbiotic culture of bacteria and yeasts. It may benefit oral health, may be a useful adjunct to stomach ulcer treatment, and may offer slight benefits to blood sugar. On the other hand, drinking kefir makes chemo side effects worse for some cancer patients. Since it contains live, active bacteria and yeasts, kefir should be used with caution by anyone with a compromised or weakened immune system.

    Kefir is most often used for .

    What is kefir?

    Kefir is a probiotic fermented milk drink made with multiple cultures of lactic acid bacteria and yeasts. There is no single starter culture, and the bacteria and yeasts vary quite a bit between different brews.[1][2]

    What are kefir's main benefits?

    The human clinical trials on kefir to date are all small. Between the small trial sizes and the massive variation in kefirs, there isn’t strong evidence that whichever kefir you take will have any given effect on you. On the other hand, if you’re a generally healthy adult, kefir is unlikely to hurt you, and may benefit your oral health.

    Kefir may also be a useful adjunct to a common treatment for stomach ulcers, and for people with type 2 diabetes, regular kefir consumption may give slight improvements to blood sugar and glycated hemoglobin (but not enough to be considered a treatment).

    What are kefir's main drawbacks?

    • Kefir has roughly the same caloric content as the milk it was brewed from, and is often additionally flavored and sweetened.
    • As it contains live, active cultures, kefir should be taken with caution by some.
    • Kefir is lower-lactose than milk, but may still contain enough lactose to trigger symptoms of lactose intolerance.[3]
    • Kefir grains can, rarely, be contaminated with pathogenic fungi or bacteria.[4]

    How is kefir taken?

    Kefir can be drunk with meals, or alone. Kefir is also used as an ingredient in several cuisines, just as other fermented milk products (yogurt, sour cream) are. When used as a probiotic, kefir shouldn’t be cooked, because that will kill the beneficial bacteria. As with other fermented milk products, there is no recommended daily minimum or maximum for kefir consumption.

    How does kefir work?

    Many of the bacteria in kefir are known probiotic species.[5] The polysaccharides produced by the kefir cultures may also be bioactive.[6]

    What are other names for Kefir

    Note that Kefir is also known as:
    • kefyr
    • kephir
    • kefier
    Kefir should not be confused with:
    • kefiran
    • water kefir
    • tibicos
    • yogurt
    • kumis
    • labneh

    Examine Database: Kefir

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    1. ^Damiana D Rosa, Manoela M S Dias, Łukasz M Grześkowiak, Sandra A Reis, Lisiane L Conceição, Maria do Carmo G PeluzioMilk kefir: nutritional, microbiological and health benefitsNutr Res Rev.(2017 Jun)
    2. ^Nor Farahin Azizi, Muganti Rajah Kumar, Swee Keong Yeap, Janna Ong Abdullah, Melati Khalid, Abdul Rahman Omar, Mohd Azuraidi Osman, Sharifah Alawieyah Syed Mortadza, Noorjahan Banu AlitheenKefir and Its Biological ActivitiesFoods.(2021 May 27)
    3. ^Steven R Hertzler, Shannon M ClancyKefir improves lactose digestion and tolerance in adults with lactose maldigestionJ Am Diet Assoc.(2003 May)
    4. ^Analy Machado de Oliveira Leite, Marco Antonio Lemos Miguel, Raquel Silva Peixoto, Alexandre Soares Rosado, Joab Trajano Silva, Vania Margaret Flosi PaschoalinMicrobiological, technological and therapeutic properties of kefir: a natural probiotic beverageBraz J Microbiol.(2013 Oct 30)
    5. ^Conor Slattery, Paul D Cotter, Paul W O'TooleAnalysis of Health Benefits Conferred by Lactobacillus Species from KefirNutrients.(2019 Jun 1)
    6. ^Maria R Prado, Lina Marcela Blandón, Luciana P S Vandenberghe, Cristine Rodrigues, Guillermo R Castro, Vanete Thomaz-Soccol, Carlos R SoccolMilk kefir: composition, microbial cultures, biological activities, and related productsFront Microbiol.(2015 Oct 30)

    Examine Database References

    1. Fecal Microbial Composition: Proportion of probiotic bacteria - Ezgi Bellikci-Koyu, Banu Pınar Sarer-Yurekli, Yakut Akyon, Fadime Aydin-Kose, Cem Karagozlu, Ahmet Gokhan Ozgen, Annika Brinkmann, Andreas Nitsche, Koray Ergunay, Engin Yilmaz, Zehra BuyuktuncerEffects of Regular Kefir Consumption on Gut Microbiota in Patients with Metabolic Syndrome: A Parallel-Group, Randomized, Controlled StudyNutrients.(2019 Sep 4)
    2. Framingham Score - Ghizi ACdS et alKefir improves blood parameters and reduces cardiovascular risks in patients with metabolic syndromePharmaNutrition.()
    3. Waist circumference - Yasamin Fathi, Shiva Faghih, Mohammad Javad Zibaeenezhad, Sayed Hamid Reza TabatabaeiKefir drink leads to a similar weight loss, compared with milk, in a dairy-rich non-energy-restricted diet in overweight or obese premenopausal women: a randomized controlled trialEur J Nutr.(2016 Feb)
    4. Glycemic Control - Alireza Ostadrahimi, Akbar Taghizadeh, Majid Mobasseri, Nazila Farrin, Laleh Payahoo, Zahra Beyramalipoor Gheshlaghi, Morteza VahedjabbariEffect of probiotic fermented milk (kefir) on glycemic control and lipid profile in type 2 diabetic patients: a randomized double-blind placebo-controlled clinical trialIran J Public Health.(2015 Feb)
    5. Low-density lipoprotein (LDL) - Marie-Pierre St-Onge, Edward R Farnworth, Tony Savard, Denise Chabot, Akier Mafu, Peter J H JonesKefir consumption does not alter plasma lipid levels or cholesterol fractional synthesis rates relative to milk in hyperlipidemic men: a randomized controlled trial [ISRCTN10820810]BMC Complement Altern Med.(2002)
    6. HbA1c - TAREK A. EL-BASHITI, BAKER M. ZABUT and FEDAA F. ABU SAFIAEffect of Probiotic Fermented Milk (Kefir) on Some Blood Biochemical Parameters Among Newly Diagnosed Type 2 Diabetic Adult Males in Gaza GovernorateCurrent Research in Nutrition and Food Science.()
    7. Fecal Microbial Load - İlkay Yılmaz, M Enver Dolar, Haydar ÖzpınarEffect of administering kefir on the changes in fecal microbiota and symptoms of inflammatory bowel disease: A randomized controlled trialTurk J Gastroenterol.(2019 Mar)
    8. Fecal Microbial Load - Mária Figler, Gyula Mózsik, Béla Schaffer, Beáta Gasztonyi, Pongrác Acs, Béla Szili, Regina Rab, Sándor SzakályEffect of special Hungarian probiotic kefir on faecal microfloraWorld J Gastroenterol.(2006 Feb 21)
    9. Loose stools - Daniel J Merenstein, Jennifer Foster, Frank D'AmicoA randomized clinical trial measuring the influence of kefir on antibiotic-associated diarrhea: the measuring the influence of Kefir (MILK) StudyArch Pediatr Adolesc Med.(2009 Aug)
    10. Depression Symptoms - Peter Smoak, Nicholas Harman, Victoria Flores, Jacob Kisiolek, Nicholas A Pullen, Jonathan Lisano, Reid Hayward, Laura K StewartKefir Is a Viable Exercise Recovery Beverage for Cancer Survivors Enrolled in a Structured Exercise ProgramMed Sci Sports Exerc.(2021 Oct 1)
    11. Uric Acid - GÖLÜNÜK, S et alEffects of traditional fermented beverages on some blood parameters in aerobic exercises.Biomedical Research.()
    12. Mood - Z Jenko Pražnikar, S Kenig, T Vardjan, M Černelič Bizjak, A PetelinEffects of kefir or milk supplementation on zonulin in overweight subjectsJ Dairy Sci.(2020 May)
    13. Sleep Latency - Gulbeyaz Can, Erkan Topuz, Duygu Derin, Zehra Durna, Adnan AydinerEffect of kefir on the quality of life of patients being treated for colorectal cancerOncol Nurs Forum.(2009 Nov)
    14. Interleukin 6 - E Topuz, D Derin, G Can, E Kürklü, S Cinar, F Aykan, A Cevikbaş, R Dişçi, Z Durna, B Sakar, S Saglam, H Tanyeri, G Deniz, U Gürer, F Taş, N Guney, A AydinerEffect of oral administration of kefir on serum proinflammatory cytokines on 5-FU induced oral mucositis in patients with colorectal cancerInvest New Drugs.(2008 Dec)
    15. Nausea Symptoms - Onder Bekar, Yusuf Yilmaz, Macit GultenKefir improves the efficacy and tolerability of triple therapy in eradicating Helicobacter pyloriJ Med Food.(2011 Apr)
    16. Bone Mineral Density - Min-Yu Tu, Hsiao-Ling Chen, Yu-Tang Tung, Chao-Chih Kao, Fu-Chang Hu, Chuan-Mu ChenShort-Term Effects of Kefir-Fermented Milk Consumption on Bone Mineral Density and Bone Metabolism in a Randomized Clinical Trial of Osteoporotic PatientsPLoS One.(2015 Dec 10)
    17. Salivary counts of Streptococcus mutans - Sevtap Alp, Zeliha Müge BakaEffects of probiotics on salivary Streptecoccus mutans and Lactobacillus levels in orthodontic patientsAm J Orthod Dentofacial Orthop.(2018 Oct)
    18. Salivary counts of Streptococcus mutans - Dilsah Cogulu et al.Potential effects of a multistrain probiotic-kefir on salivary Streptococcus mutans and Lactobacillus spp.J Dent Sci .()
    19. Salivary counts of Streptococcus mutans - Maryam Ghasempour, Seyyed Ali Asghar Sefdgar, Ali Akbar Moghadamnia, Reza Ghadimi, Samane Gharekhani, Leila ShirkhaniComparative study of Kefir yogurt-drink and sodium fluoride mouth rinse on salivary mutans streptococciJ Contemp Dent Pract.(2014 Mar 1)
    20. Interleukin 5 - Ali Kudret Adiloğlu, Nurettin Gönülateş, Mehmet Işler, Altuğ Senol[The effect of kefir consumption on human immune system: a cytokine study]Mikrobiyol Bul.(2013 Apr)
    21. Time to run/walk 1.5 miles - K V O'Brien, L K Stewart, L A Forney, K J Aryana, W Prinyawiwatkul, C A BoenekeThe effects of postexercise consumption of a kefir beverage on performance and recovery during intensive endurance trainingJ Dairy Sci.(2015 Nov)
    22. Constipation Signs and Symptoms - İlker Turan, Özden Dedeli, Serhat Bor, Tankut İlterEffects of a kefir supplement on symptoms, colonic transit, and bowel satisfaction score in patients with chronic constipation: a pilot studyTurk J Gastroenterol.(2014 Dec)