6 Health Benefits Of Kefir, According To Nutrition Experts (2024)

Kefir is a fermented beverage traditionally made with milk or water and kefir “grains”. Kefir grains are small white to light yellow gelatinous mixtures of probiotic microorganisms, including lactic acid bacteria, yeasts and acetic acid bacteria. The bacterial makeup of the kefir grains, which are predominantly Lactobacillus bacteria, depends on the climate conditions in which the kefir grains develop.

“Kefir is a nutrient-dense beverage that offers high-quality protein, calcium and vitamins A, D and B12,” says Megan Maisano, an Ohio-based registered dietitian and director of nutrition and regulatory affairs at the National Dairy Council. It also contains lactic, acetic and glycolic acids, a small amount of ethyl alcohol, carbon dioxide and polysaccharides.

Kefir is slightly fizzy with an acidic taste. On its own, kefir isn’t sweet—though many commercial kefirs contain added sugars and flavors.

The two general types of kefir are dairy and non-dairy.

Dairy Kefir

Kefir is traditionally made by adding kefir grains to pasteurized or boiled and cooled milk. It is allowed to ferment for between 18 to 24 hours before the kefir grains are filtered out. After another 24 hours of refrigeration, the kefir is ready to enjoy^[1]Pereira TMC, Côco LZ, Ton AMM, et al. The Emerging Scenario of the Gut–Brain Axis: The Therapeutic Actions of the New Actor Kefir against Neurodegenerative Diseases. Antioxidants. 2021;10(11). .

Dairy kefir can be made with any type of milk, including goat, buffalo, sheep, camel or cow milk. The type of milk used affects the flavor and microbial composition of the kefir.

Non-Dairy Kefir

Dairy-free kefir may be a good option for people who cannot or choose not to consume milk. Non-dairy kefirs can be made with water and brown sugar, known as water kefir or sugary kefir, as well as non-dairy milks like soy milk.

While much of the research examining kefir’s health benefits has been conducted on dairy kefir, the microbial content of non-dairy kefir is similar to that of traditional dairy kefir.

Kefir may offer a number of health benefits, including promoting gut microbial health, helping manage blood sugar and reducing inflammation. Read on to learn what current research says about kefir’s potential health benefits.

Good Source of Probiotics

“Kefir contains various strains of live bacteria, making it a rich and diverse probiotic source,” says Julie Balsamo, a Jackson, Wyoming-based registered dietitian specializing in gut health.

Probiotics are living microorganisms, including bacteria and yeast, that offer health benefits. Some of the potential benefits of probiotics include their ability to alter the composition of bacteria in the gut, improve intestinal barrier function, support healthy digestion and help produce short-chain fatty acids—compounds associated with health and lower risk of chronic disease—and certain vitamins. They may also help modulate the immune system and decrease inflammation.

The gut is lined with different species of bacteria, says Boston-based registered dietitian Alyssa Pacheco, “and more diverse gut microbiomes have been linked to better health outcomes.”

A review of 19 studies examining the effect of fermented foods, including kefir, on the gut microbiota found that these foods help modify the microbial makeup of the gut and may help improve immunity and metabolic factors^[2]Bellikci-Koyu E, Sarer-Yurekli BP, Akyon Y, et al. Effects of Regular Kefir Consumption on Gut Microbiota in Patients with Metabolic Syndrome: A Parallel-Group, Randomized, Controlled Study. Nutrients. 2019;11(9). .

In one small study examining kefir’s effect on gut bacteria specifically, people with metabolic syndrome who consumed 180 milliliters of kefir daily for 12 weeks had a significant increase in Actinobacteria in the gut, improved insulin and lowered blood pressure levels^[3]Stiemsma LT, Nakamura RE, Nguyen JG, Michels KB. Does Consumption of Fermented Foods Modify the Human Gut Microbiota?. J Nutr. 2020;150(7):1680. .

May Aid in Blood Sugar Management

Consuming kefir may help manage blood sugar levels, especially in people with type 2 diabetes.

In one small 2015 study, 60 people with type 2 diabetes consumed either 600 milliliters of kefir twice a day or a placebo for eight weeks. Those who consumed the kefir had significantly lower hemoglobin A1c (HgA1c), a measure of blood sugar over time, compared to placebo^[4]Ostadrahimi A, Taghizadeh A, Mobasseri M, et al. Effect of Probiotic Fermented Milk (Kefir) on Glycemic Control and Lipid Profile In Type 2 Diabetic Patients: A Randomized Double-Blind Placebo-Controlled Clinical Trial. Iran J Public Health. 2015;44(2):228. .

Another small study from 2019 shows that consuming one cup of kefir daily decreased fasting blood glucose, HgA1c levels and insulin resistance in patients with newly diagnosed type 2 diabetes, says Caroline Margolis, a registered dietitian with Lifeway Foods in Michigan^[5]El-Bash*ti TA, Zabut BM, Safia FFA. Effect of probiotic fermented milk (Kefir) on some blood biochemical parameters among newly diagnosed type 2 diabetic adult males in Gaza governorate. Current Research in Nutrition and Food Science. 2019;7(2):568-575. .

Might Reduce Inflammation

Studies suggest kefir may aid in reducing inflammation by inhibiting the activity of proinflammatory cytokines—proteins that play a role in pain and inflammation—and increasing anti-inflammatory cytokine concentrations to reduce the risk of certain diseases and disease-related complications, says Margolis.

In one small study examining the effect of kefir on markers of metabolic syndrome, 62 people with metabolic syndrome consumed either 180 milliliters of kefir or unfermented milk daily for 12 weeks. Those who consumed the kefir had significantly increased apolipoprotein A1, a major component of HDL “good” cholesterol, and decreased cytokines compared to those who drank the unfermented milk^[6]Bellikci-Koyu E, Sarer-Yurekli BP, Karagozlu C, Aydin-Kose F, Ozgen AG, Buyuktuncer Z. Probiotic kefir consumption improves serum apolipoprotein A1 levels in metabolic syndrome patients: a randomized controlled clinical trial. Nutrition Research. 2022;102:59-70. .

May Improve Brain Health and Mood

“While studies indicate that kefir, along with a diet rich in fiber, may balance the microbiome to reduce the risk and symptoms of psychological disorders such as anxiety and depression, it may also have an effect on memory and cognition, and a reduced risk of neurological diseases, thanks to its ability to reduce inflammation,” says Margolis.

It’s important to include fiber when consuming probiotics as fiber is the fuel used by probiotic organisms while in the GI tract.

In one small study examining the effect of kefir on memory, adults who consumed 8 ounces of kefir daily for four weeks had significantly improved relational memory and increased concentration of Lactobacillus in the gut compared to a placebo^[7]Cannavale CN, Mysonhimer AR, Bailey MA, Cohen NJ, Holscher HD, Khan NA. Consumption of a fermented dairy beverage improves hippocampal-dependent relational memory in a randomized, controlled cross-over trial. Nutr Neurosci. 2023;26(3):265-274. .

Helps Build Stronger Bones

As kefir is a dairy product containing calcium, vitamin D and phosphorus, it may help build and maintain strong bones, says Maisano. A review of studies examining important nutrients for bone health found that fermented dairy products are associated with a reduced risk of hip fracture^[8]Rizzoli R. Dairy products and bone health. Aging Clin Exp Res. 2022;34(1):9. .

Helps Protect Against Viruses

Kefir’s anti-viral properties can help your immune system fight off viral infections, says Pacheco. A review of studies examining kefir’s effects on the immune system found that kefir promotes production of immune cells that can suppress viral activity^[9]Hamida RS, Shami A, Ali MA, Almohawes ZN, Mohammed AE, Bin-Meferij MM. Kefir: A protective dietary supplementation against viral infection. Biomedicine & Pharmacotherapy. 2021;133:110974. .

“Most research shows there’s very little to no risk [to] consuming kefir,” says Maisano.

“Kefir is generally safe to consume,” agrees Balsamo. However, some people may experience temporary digestive issues like bloating, gas or diarrhea when first introducing live bacteria into their system, she adds.

“The good news is these symptoms usually settle down after a few days,” notes Balsamo, who recommends slowly introducing probiotic-rich foods like kefir to help negate these side effects.

“Traditional kefir is usually milk-based, so anyone with a milk allergy should avoid kefir,” says Pacheco. However, most people with lactose intolerance can tolerate milk kefir because it’s generally low-lactose or lactose-free, she adds. The lactobacillus helps break down the lactose, which eases the digestion process, particularly for those who may be lactose intolerant.

“Kefir’s live and active cultures help break down the lactose from milk, making it easier for people with lactose intolerance to enjoy,” agrees Maisano.

“If you don’t tolerate milk well or follow a vegan diet, there are non-dairy kefir options, which are typically referred to as water kefir,” explains Pacheco, noting that water kefir provides similar benefits as milk kefir.

“Due to the fermentation process, some kefirs may contain small amounts of alcohol,” says Maisano. “People who are pregnant or avoiding alcohol should check the label and consult their health care provider.”

Further, people with compromised immune systems should consult their health care provider before consuming kefir, since it contains live and active cultures, adds Margolis.

Kefir comes in a variety of flavors that can be enjoyed on their own—blueberry, guava or mixed berry are some favorites of Michigan-based culinary registered dietitian and owner of The Kitchen Invitation, Jessi Holden. She also enjoys including plain or flavored kefir in a smoothie or smoothie bowl topped with nutrient-dense foods like nuts, hemp hearts and granola.

Balsamo generally recommends unflavored kefir, which has a slightly sour and tangy taste. “The flavored options often contain large amounts of added sugars,” she says.

“Kefir can be enjoyed in a variety of ways,” says Maisano. “Mix it in a smoothie or overnight oats for a protein and probiotic punch, use it as a nutritious base for a creamy salad dressing or simply sip on it as a tart and tangy beverage.”

Kefir can also replace other dairy products in your favorite recipes to give them a nutrient-rich probiotic boost, according to Margolis. “While many of the probiotic bacteria won’t survive being cooked, kefir is a great way to add flavor and texture to warm dishes and make baked goods extra fluffy.” Margolis offers the following tips to incorporate kefir into everyday recipes:

• Mix kefir into pancake or waffle batter
• Make chia pudding with kefir instead of milk
• Choose plain kefir over mayo or sour cream to cut calories and fat without sacrificing flavor in favorite dips and dressings
• Add kefir to soups, hummus and other spreads for extra tang
• Use kefir as a base for protein marinade—its tanginess works well with herbs and spices to impart fresh flavor and the lactic acid and probiotic cultures help tenderize tough cuts of meat
• Use kefir as a base for puddings, popsicles, ice cream and frostings