The Benefits of Kefir

Kefir is a fermented milk product made using kefir grains (a specific combination of live lactic acid bacteria and yeast). Rich in a variety of probiotic bacteria and yeast, many people drink kefir for health purposes as an alternative to yogurt (which is normally made using a few types of probiotic cultures).

Kefir has a thinner consistency than yogurt and is typically sold as a beverage. Most kefir products are tangy and fizzy, due to the greater probiotic activity.

Woman sipping a cup of milk
Sarayuth Punnasuriyaporn / EyeEm / Getty Images


Probiotics are normally found in your intestines as part of your gut flora, a complex mixture of over 400 species of "good" and "bad" bacteria and microorganisms. Proponents claim that they can help boost immunity and improve digestive health.

In addition, kefir is touted as a remedy for a number of common health conditions, including:

  • Acne
  • Allergies
  • Chronic fatigue syndrome
  • Constipation
  • Depression
  • Diabetes
  • Eczema
  • High blood pressure
  • High cholesterol
  • Insomnia
  • Irritable bowel syndrome (IBS)


Although a number of studies suggest that probiotics may offer certain health benefits, research on the specific health effects of kefir is fairly limited. However, there's some preliminary evidence that kefir may help enhance immunity, reduce inflammation and fight bacterial infections.

Lactose Intolerance

Kefir may help some individuals overcome lactose intolerance, suggests a small study published in the Journal of the American Dietetic Association in 2003. For the study, 15 healthy adults with lactose intolerance were fed a series of meals that contained milk and either kefir or yogurt. Results revealed that the bacteria in kefir help break down the majority of lactose present, thereby improving lactose digestion and tolerance. In addition, both kefir and yogurt appeared to reduce abdominal pain and diarrhea among participants.

Bone Density

Kefir shows promise as a natural means of improving your bone mineral density, as it contains both calcium and Vitamin K2, which helps with the absorption and metabolism of calcium, necessary for bone health. A six-month study comparing the effects of kefir supplemented with calcium bicarbonate to calcium bicarbonate alone in people with osteoporosis found that the kefir treatment was associated with increased hip bone mineral density.

Antibiotic-Associated Diarrhea

Although kefir is often recommended for certain side effects associated with the use of antibiotics, a 2009 study from the Archives of Pediatrics and Adolescent Medicine indicates that kefir may fail to fight antibiotic-related diarrhea. In tests on 125 children taking antibiotics, researchers found that kefir was no more effective than a placebo in preventing antibiotic-associated diarrhea.

High Cholesterol

Many proponents suggest that kefir can shield heart health by keeping your cholesterol in check. A small study published in BMC Complementary and Alternative Medicine, however, found that kefir consumption didn't lower plasma lipid levels. For the study, male participants consumed kefir or a non-fermented milk product (with similar fat, cholesterol, and calorie content). Neither beverage decreased total cholesterol, HDL cholesterol, LDL cholesterol, or triglyceride levels.

Possible Side Effects

Although kefir drinks are generally considered safe when consumed in moderation, it may cause certain side effects (such as constipation, gas, and intestinal cramping).

According to a study published in the Journal of the American College of Nutrition, kefir is a low- to moderate-GI (glycemic index) food, however, it is high on the insulinemic index (causing a greater release of insulin) and has a satiety index not significantly different from white bread.

As with other fermented products, there is a small amount of naturally-occurring alcohol in kefir.

It's important to note that kefir shouldn't be used to self-treat a health condition and/or avoid standard care.

Where to Find It

Widely available in natural-food stores, kefir is now sold in many grocery stores.

A Word From Verywell

While drinking kefir can boost your probiotic intake and provide calcium, protein, and other minerals and vitamins, we can't be as solid about whether it can treat any health condition because of the lack of large, well-controlled studies in people (the kind of research you want to see to put full stock in a treatment).

That said, if you normally eat yogurt, you may enjoy kefir's tangy, creamy taste. Just be sure to check labels and choose a product that has minimal added sugar.

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  • Hertzler SR, Clancy SM. Kefir improves lactose digestion and tolerance in adults with lactose maldigestion. J Am Diet Assoc. 2003 May;103(5):582-7.
  • Merenstein DJ, Foster J, D'Amico F. A randomized clinical trial measuring the influence of kefir on antibiotic-associated diarrhea: the measuring the influence of Kefir (MILK) Study. Arch Pediatr Adolesc Med. 2009 Aug;163(8):750-4.
  • St-Onge MP, Farnworth ER, Savard T, Chabot D, Mafu A, Jones PJ. Kefir consumption does not alter plasma lipid levels or cholesterol fractional synthesis rates relative to milk in hyperlipidemic men: a randomized controlled trial. BMC Complement Altern Med. 2002;2:1.
  • Tu MY, Chen HL, Tung YT, Kao CC, Hu FC, Chen CM. Short-Term Effects of Kefir-Fermented Milk Consumption on Bone Mineral Density and Bone Metabolism in a Randomized Clinical Trial of Osteoporotic Patients. PLoS One. 2015 Dec 10;10(12):e0144231.