What Exactly Is Kefir? Here Are The Benefits + How To Make It At Home

Studies continue to come out about the gut microbiome and its role in digestion, healthy skin1, cognitive functioning2, and even immune support3. As people become more aware of these connections, probiotic-rich foods are becoming more popular. If you're already sipping kombucha and eating yogurt, you may also want to check out kefir. 

Kefir is a fermented dairy product similar to yogurt, but thinner and meant for drinking. Similar to sourdough, kefir is made from a starter. The starter is primarily made of probiotics (called kefir grains), yeast, and milk proteins. 

The dairy beverage originated in Eastern Europe4 and has since been commercialized in other regions of the world, including the U.S., Canada, and Great Britain. 

Integrative gastroenterologist Martin Singh, M.D., tells mbg, "just make sure to avoid kefir with added sugar and flavorings." Instead look for plain, full-fat varieties.

And while not technically kefir, there are aqua kefirs or water-based kefirs, which are a good dairy-free option if you're extremely sensitive to lactose. You can make your own water kefir at home or purchase the sparkling beverage from brands like GT's Living Foods.

Both yogurt and kefir are fermented foods that are high in probiotics5. These beneficial bacteria have been proved to reduce risks of metabolic diseases, heart disease, and support weight management. Though they're both rich in probiotics, kefir has a larger range of the beneficial Lactobacillus bacteria.

In terms of flavor, registered dietitian Ali Miller, R.D., L.D., CDE, tells us plain dairy kefir is relatively similar to the tang of non-strained plain yogurt. Both yogurt and kefir come in fruit-flavored varieties, but those may contain added or excess sugar. 

Texture-wise, dairy kefir is thinner than yogurt—especially Greek yogurts—and water kefir will often be effervescent, like seltzer water or kombucha. 

Kefir has a wide range of health benefits. For starters, it contributes to better gut health by delivering good bacteria to the microbiome and helping to synthesize vitamins B12 and K, says registered dietitian Kayleen St. John, M.S., R.D. The beneficial gut bacteria can aid in digestion and help reduce bloat. 

According to one study, consuming kefir has also been linked to inflammation management, better cholesterol levels, and healthy blood pressure6. 

Unlike most dairy products, kefir is low in lactose and relatively easy to digest. In fact, research specialist in oncology nutrition L.J. Amaral M.S., R.D., CSO, says it's about 99% lactose-free. If that's still too much, you can opt for aqua kefir. 

According to the U.S. Department of Agriculture (USDA), one bottle of kefir7 contains: 

These values may vary depending on brand. 

Introducing probiotics to your diet can have varying effects, depending on the current state of your gut microbiome. "If the gut is in a balanced state, it should be well tolerated," Miller says. If it's in an unbalanced state (dysbiosis), you may notice side effects.  

These side effects may include irregular bowel movements, bloating, distention, skin irritation, migraines, or other inflammatory responses, she says. If you start experiencing these symptoms, stop drinking kefir and consult your doctor. A physician or a registered dietitian may help you work toward a healthier gut.

Making kefir at home is relatively simple. "If you have time to spend in the kitchen, making plain kefir can be cheaper than buying it at the store," registered dietitian Nour Zibdeh, M.S., RDN, tells mbg. All it takes is two ingredients and a few supplies. 

You can save the kefir grains in a small container of fresh milk in the fridge until you're ready to make another batch.

Store your kefir, with the lid on, for up to one week in the fridge. If you notice any separation, use a whisk to mix your kefir back together.