As you eye a bottle of kefir on a grocery store shelf, you may ask yourself: Is it milk? Is it yogurt? (And how do you pronounce it, anyway?) In fact, kefir is a little bit like both. Pronounced “keh-feer,” it’s a fermented milk beverage with many similar properties to yogurt.
Kefir is typically made by fermenting cow, goat, or sheep milk using a bacterial culture of polysaccharides called kefiran. As these bacteria get to work on fermentation, they create high doses of probiotics and a fizzy pop some people say is similar to that of beer. In taste and texture, kefir has a thin, drinkable consistency. Its flavor is strong and tangy.
Long touted by holistic health practitioners as a remedy for everything from acne to depression, kefir isn’t just for the alt-medicine crowd. High in calcium and probiotics, this creamy beverage with Eastern European roots has documented health benefits everyone can enjoy.
This nutrition information, for 1 cup (8 oz.) of plain kefir is provided by the USDA.
Although kefir is an animal product, which some people associate with low levels of carbohydrates, it’s not carb-free. This is due to naturally occurring sugars in its milk base. However, the fermentation that turns milk into kefir “eats” some of these sugars. Compared to an 8-ounce glass of 2% milk, which contains 12 grams of carbs, an 8-ounce serving of kefir contains just 9 grams.
When converting milk to kefir, fermentation won’t change its fat content. Made with whole milk, kefir contains 8 grams of fat.
Whole milk’s fat composition skews toward the saturated variety, with 62% saturated, 30% monounsaturated, and 4% polyunsaturated fats. Despite saturated fat’s negative reputation, however, many experts believe that, when consumed in whole dairy, it offers protective effects for heart health.
Like a glass of milk, 8 ounces of kefir provides 8 grams of complete protein. This means it contains all the essential amino acids your body can’t produce on its own.
As a dairy product, kefir is high in calcium. One serving provides 300 milligrams, or 30% of the Daily Value. You’ll also find modest amounts of vitamin A (6% DV) and sodium (4% DV) in an 8-ounce glass.
There are many ways drinking kefir can positively impact your health.
Research shows that eating fermented foods comes with a variety of benefits, including building a healthier immune system. The live cultures in kefir cultivate a healthy microbiome, which supports immunity.
When you’re all stopped up, a bit of kefir may help. In a 2014 study of 20 subjects with chronic constipation, drinking 500 milliliters (about 17 ounces) of kefir a day for four weeks improved the frequency and consistency of bowel movements.
For those who can’t tolerate the lactose in milk, kefir may be a viable alternative. An older study in the Journal of the American Dietetic Association found that drinking kefir improved lactose digestion and tolerance in 15 healthy subjects.
Autoimmune disorders are often fueled by inflammation in the body. The probiotics in kefir may be one strategy for taming this inflammation. More study is needed on the subject, but preliminary research shows that probiotics may improve symptoms in rheumatoid arthritis, ulcerative colitis, and multiple sclerosis.
Evidence of the health benefits of probiotics is promising, but more research is needed for them to be recommended as treatment for any health conditions. In the American Gastroenterological Association's 2020 Clinical Practice Guidelines, the use of probiotics is recommended only in the context of clinical trials for most gastrointestinal issues.
The plentiful calcium in kefir is a known bone-builder. Getting enough of this micronutrient helps your body’s continual remodeling and recreation of healthy bone tissue.
A 2015 review that assessed 11 individual studies “consistently showed beneficial effects of kefir on cancer prevention and treatment.” The review focused on breast, colon, skin, and gastric cancers, as well as leukemia. This research may not be enough to draw firm conclusions on kefir’s effects on cancer, but it is promising.
While kefir may be a satisfying milk alternative for those with lactose intolerance, the same isn’t true for people with a milk allergy. Kefir still contains casein and whey, the proteins that cause allergic reactions. If you have a known milk allergy, you shouldn’t drink kefir.
For most people, kefir is a healthy, probiotic-rich addition to the diet. But for some, it may cause gastrointestinal distress in the form of gas or intestinal cramping.
Additionally, kefir might not be suitable for people who can’t tolerate alcohol or have a history of alcoholism. A 2019 Australian study found that over 36% of water-based kefirs had an alcohol content greater than 1.5%. Although the amount of alcohol in kefir is usually quite small, it’s best to err on the side of caution if you have trouble with alcohol.
Like regular dairy milk, you can find kefir with various flavor additions, such as strawberry or chocolate. Just be aware that these flavorings may add calories and sugars. Similarly, kefir can start with anything from non-fat to whole milk, which will also affect its calorie and fat content.
Kefir isn’t just for omnivores, either. Alt-milk versions that use coconut or almond milk are available for vegans (or anyone who prefers their taste).
Meanwhile, there’s another kefir variety that’s gained an increasing following in recent years: water kefir. Sometimes called tibicos, this beverage uses the same fermentation process as dairy kefir with a water base. Sweeteners and flavorings, many of them fruity, are typically added.
Kefir should be kept cold in the refrigerator, both before and after opening. Once opened, it should last in the fridge for about five days.
Since kefir already has a somewhat sour smell, it may be tough to tell when it has gone bad. However, you can always use your eyes and nose to check for signs of freshness. Kefir with an extremely strong odor or visible mold, fuzz, or spots should be thrown away. Other signs the beverage has gone bad include clumping or color changes.
While it’s most convenient to purchase pre-made kefir, you can also make it yourself! All you need is milk and kefir “grains,” AKA the bacterial and yeast culture that causes fermentation. Kefir grains are available for purchase as a powder. Add about one teaspoon of this powdered starter to 8 ounces of milk, cover, and store at room temperature for 24 hours. (Don’t worry, the fermentation process will keep the mixture from spoiling.)