What Are Kefir and Its Health Benefits?

Medically Reviewed by Jabeen Begum, MD on October 13, 2023
Written by Hallie Levine, WebMD Editorial Contributor
6 min read

Kefir, pronounced kee-feer, is a drink made from the fermented milk from a cow, goat, or sheep. Water kefir is similar but has a water base instead of milk.

Historians believe kefir originated centuries ago in the Caucasus Mountains in Eastern Europe near present-day Turkey. The word kefir is derived from the Turkish word “keif,” which translates to “good feeling.” 

Kefir contains around 60 unique species of probiotics, “good bacteria” that improve gut health and may aid in your digestive processes. The most common are lactobacillus, lactococcus, streptococcus, and leuconostoc.

You can buy kefir at grocery and health food stores or make your own.

Is kefir lactose free?

Kefir is low in lactose, the sugar in milk. That means that you can probably drink it even if you're lactose intolerant. In fact, research shows that drinking kefir may actually help improve lactose digestion and intolerance. 

There are dairy-free versions of kefir you can buy but they don’t have the same nutritional profile and benefits as regular kefir.

Kefir comes in many forms, including:

  • Kefir milk is a drink made from the fermented milk from a cow, goat, or sheep, and kefir grains.
  • Water kefir is another fermented drink that’s made with a mix of sugar water and kefir grains. It’s entirely dairy free.
  • Kefir grains are colonies of yeast and bacteria that look like small pieces of cauliflower. They have probiotic microorganisms that break down the lactose in milk, which causes fermentation. There are two types of kefir grains: water grains (that you mix with sugar water) and milk grains (that you mix with milk).
  • Raw kefir is kefir made from raw milk (unpasteurized). It’s illegal to buy raw milk in many states because it can have harmful bacteria. However, studies show raw milk kefir has specific beneficial bacteria and yeast that aren't in pasteurized milk kefir. 

There's no such thing as kefir yogurt, but kefir is often compared to yogurt, and in some ways, the two products are similar. 

Like yogurt, kefir has a slightly sour flavor and is created through fermentation. They’re both good options if you're lactose intolerant, since you can digest them easily. 

Also, kefir and yogurt contain different types of good bacteria. Kefir’s main beneficial bacteria is Lactobacillus kefiri, while yogurt's are mainly Lactobacillus bulgaricus and Streptococcus thermophilus. Yogurt also has only bacteria, while kefir has bacteria and yeast.

Kefir's consistency is thinner than yogurt and yogurt drinks, and kefir also tends to have fewer calories and sugar than yogurt.

The two do have one thing in common: Both make great bases for smoothies or to mix with cereal or fruit. Just stick to plain, as it's lower in calories and sugar than flavored.
 

One cup of low-fat kefir  contains: 

  • Calories: 104
  • Protein: 9 grams
  • Fat: 2.5 grams
  • Carbohydrates: 11.5 grams
  • Fiber: 0 gram
  • Sugar: 11 grams

Kefir is a good source of: 

  • Vitamin B12
  • Calcium
  • Vitamin K
  • Riboflavin
  • Folate
  • Phosphorous

Kefir's probiotics and nutrients support digestive and gut health.

But drinking kefir may also benefit you in other ways too.

Supports digestion

Kefir can have as many as 61 strains of bacteria. Studies show these powerful microorganisms may help treat and prevent gastrointestinal diseases like irritable bowel syndrome, some kinds of diarrhea, and ulcers caused by the infection H. pylori. 

Improves heart health 

Research shows that kefir can reduce damage caused by metabolic syndrome (multiple health conditions that can increase your risk of heart disease). Kefir helps lower your blood pressure, manage your cholesterol levels, and improve your triglycerides (fats in the blood). It may even help prevent future cardiac events. 

Improves bone health and reduces the risk of osteoporosis

Kefir is a good source of calcium, which you need for good bone health. One study found that people with osteoporosis who drank kefir milk daily showed improvements in their bone mineral density. Kefir is also rich in other bone-building nutrients, including vitamin D, phosphorus, magnesium, and vitamin K.

Has antibacterial properties

Some of the probiotics in kefir may be as good at fighting certain harmful bacteria as antibiotics. Lactobacillus kefiri, which is only found in kefir, can even slow or stop the growth of dangerous bacteria like salmonella, H. pylori, and E. coli.

Helps manage blood sugar

If you have type 2 diabetes, adding kefir to your diet may help. Research shows that drinking kefir can lower your body's fasting blood sugar levels, and it may help you control other markers linked to diabetes like insulin resistance and blood pressure, but we need more research to know for sure.
 

 

 

 

 

There are very few downsides to kefir. But there are a few things to be aware of:

You can get gas and bloating when you start eating and drinking foods rich in probiotics like kefir, so start out with a little. You can always drink more as your body adjusts.

Kefir contains very small amounts of alcohol. It’s not an issue for most people, but if you’re sensitive to alcohol’s effects or you avoid alcohol for any reason, you may need to skip kefir.

Be careful if you have a weakened immune system. If you’ve recently finished cancer treatment, for example, or have a condition like HIV, talk to your doctor before you add kefir to your diet. Most of the time, it’s safe, but very rarely, probiotics have been linked to serious infections like sepsis.

Be aware of GI side effects. If you drink kefir, you may notice the following:

  • Cramping
  • Nausea
  • Soft poops
  • Gas
  • Changes to taste

Medication interactions

Kefir has lots of live bacteria and yeast, which your immune system usually controls to prevent infections. But if you take immunosuppressants (medicines that decrease your immune function), you could get sick from kefir.

Some medications that decrease the immune system include: 

  • Azathioprine (Imuran) 
  • Basiliximab (Simulect) 
  • Corticosteroids
  • Cyclosporine (Neoral, Sandimmune) 
  • Daclizumab (Zenapax) 
  • Muromonab-CD3 (OKT3, Orthoclone OKT3) 
  • Mycophenolate (CellCept) 
  • Prednisone (Deltasone, Orasone)
  • Sirolimus (Rapamune) 
  • Tacrolimus (FK506, Prograf) 

Kefir is surprisingly easy to make. All you need is some milk, a glass jar, and kefir grains, which you can buy online. 

Here’s how to do it:

  1. Place a few teaspoons of kefir grains and 1 cup of milk in a glass jar. This is one time where full fat milk is best; it gives the kefir better consistency.
  2. Cover the jar with a dish towel or paper towel, then secure it with a rubber band.
  3. Let the jar sit at room temperature for 24-48 hours. The milk will gradually start to thicken as the grains ferment.
  4. Drain the kefir through a cheese cloth into a cup, squeezing it to help the liquid strain through.
  5. Save the strained kefir grains for your next batch.
     

Kefir is a fermented drink made with milk or water and kefir grains. Its consistency and flavor are similar to yogurt drinks, but kefir has more probiotics and good bacteria. Several studies show that drinking kefir can help improve your digestive and bone health and maintain your blood sugar levels. You can buy kefir or make it at home. 

Which is healthier, kefir or yogurt?

Both are good for you, but the main difference is kefir has more probiotics and a bit less sugar than yogurt. So if you want one for your gut health, kefir is better.

Is it OK to drink kefir every day?

Most people can drink kefir every day without any problem. But if you have a weakened immune system, talk to your doctor before you start drinking it. Some studies show probiotics can cause infection in people who are immunocompromised.