What Is Kefir?

Medically reviewed by Debra Rose Wilson, PhD, MSN, RN, IBCLC, AHN-BC, CHT on October 9, 2017Written by Ana Gotter on June 21, 2017


Kefir is a cultured, fermented beverage that tastes a great deal like a yogurt drink. It’s made using “starter” grains, just as sourdough bread has a “starter.” This starter is a combination of yeasts, milk proteins, and bacteria. It has a tart, creamy flavor, and it’s loaded with probiotic health benefits.

Kefir is most commonly made with dairy milk, but it can be made with non-dairy alternatives including:

  • coconut milk
  • goat’s milk
  • rice milk
  • coconut water

Because kefir is fermented, most people who are lactose intolerant can actually drink kefir.

Kefir is now widely accessible in most places. It can be found in some form in most grocery stores near the dairy or yogurt. It’s often used to improve digestion.

Kefir vs. yogurt

Kefir and yogurt are sometimes lumped together as being nearly identical products, but this isn’t accurate.

Kefir and yogurt do have a lot in common. They both have similar creamy-but-tart tastes and are traditionally made from dairy (but can be made with alternatives). They also both have plenty of protein, calcium, B vitamins, potassium, and probiotics.

However, they do have significant differences. Kefir typically has more fat than yogurt, but it also has more protein and more probiotics. Kefir is also thinner and is best as a drink. Yogurt has a thicker consistency.

Kefir and yogurt are made differently. Kefir ferments at room temperature, while many types of yogurt start culturing under heat. Kefir contains a larger number of different types of healthy bacteria, and it’s better for the gastrointestinal tract because of this. Kefir’s active yeast also has more nutritional benefits than that of yogurt.

Health benefits of kefir

Part of the reason kefir has become more accessible and widespread in the past few years is likely due to its health benefits.

Kefir is nutrient-dense, with plenty of protein, B vitamins, potassium, and calcium. Calcium helps to build strong bones, protein builds strong muscles, and potassium is essential for heart health.

The probiotics are the strongest health benefit that kefir has to offer. According to the Mayo Clinic, probiotics can help to:

  • improve the healthy bacteria ratio in the gastrointestinal tract’s environment
  • treat or prevent diarrhea, especially following antibiotic treatment
  • treat irritable bowel syndrome, or relieve symptoms
  • reduce or prevent gastrointestinal infections, or increase recovery from them
  • prevent and treat vaginal infections
  • prevent and treat urinary tract infections

Kefir’s health benefits even extend outside of its probiotics. One study found that mice who consumed kefir for seven days experienced anti-inflammatory and healing effects. Another study found that kefir may be beneficial in lowering cholesterol and stimulating the immune system.

Since kefir is safe to consume as a food, it may have fewer side effects than other probiotic supplements. It’s also more nutritionally dense than other probiotic supplements. There is current research that focuses on many other benefits of a healthy gut biome with diverse bacteria.

Side effects of kefir

While kefir has plenty of great health benefits, it also has some side effects. These include constipation and abdominal cramping. These side effects are most common when you first start taking kefir.

Kefir is considered to be safe for children between 1 and 5 years of age, but ask their pediatrician first if you have concerns. Children under 1 year of age should not have cows’ milk products, but breast milk is high in natural probiotics.

You should consult your doctor before drinking kefir if you have AIDS or other conditions that weaken the immune system. People with autoimmune diseases should also talk to their doctor before using kefir. While the bacteria in kefir is beneficial for people with strong immune systems, it may increase infections or exacerbations of conditions in those whose immune systems are out of balance.

Kefir is made with caseins, which some people eliminate from their diet. If you have eliminated caseins from your diet, it may be best to skip kefir and try another probiotic instead.

What the research says

Most, if not all, major superfood and health food fads are researched by scientists, and so far, most of the research about kefir is positive. One study found that kefir possessed strong antimicrobial, anti-inflammatory, antioxidant, and anti-tumor properties.

Research has shown that kefir may also help improve the digestive system in multiple ways, including direct pathogen inhibition and the increased production of healthy bacteria. It may even be effective in treating peptic ulcers.


Kefir is safe for most people to consume, and a single serving is full of vitamins and probiotics. It’s safe to consume daily, and it may help create and maintain a healthy balance of good bacteria in multiple systems within the body.

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