Kefir vs. Yogurt: Which Is the Better Probiotic for Your Gut? (2025)

Kefir

Fermentation

Kefir is a type of fermented milk, usually cow's milk. It has an acidic, almost citric, sour taste. Kefir contains kefir grains, live bacteria, and yeast.

Kefir grains are a community of lactic acid bacteria, acetic acid bacteria, yeasts, and other microorganisms. Kefir grains are complex, and their makeup varies from colony to colony. The lack of standardization makes studying the health effects of kefir difficult.

Where to Get

Kefir is available in stores, but people also make it at home with kefir grains. Kefir contains many bacterial and yeast species, including Lactobacillus and Saccharomyces. The strains in kefir are variable.

How It Is Made

People make kefir by placing a small amount of kefir grains in milk, usually cow's milk. The mixture is left in a sealed container at room temperature for up to a day until the milk thickens. The kefir grains are strained out and saved for use when creating the next batch.

Kefir might also be made using:

• Sheep's milk
• Goat's milk
• Coconut milk
• Oat milk
• Water
• Juice

Nutritional Info

The nutritional makeup of 1 cup of low-fat kefir from cow's milk includes:

• Calories: 104
• Fat: 2 grams (g)
• Sodium: 97 milligrams (mg)
• Carbohydrates: 12 g
• Sugars: 11 g
• Protein: 9 g
• Calcium: 316 mg
• Potassium: 399 mg
• Lactose: 9 g

Yogurt

Fermentation

Yogurt is milk fermented using heat and a bacterial culture. The bacteria act on the lactose in milk, changing it to lactic acid. The milk thickens and becomes yogurt.

Yogurt contains probiotics and nutrients. Due to the fermentation process, it is lower in lactose than milk, potentially making it more digestible for those with lactose intolerance (an inability to digest lactose, a sugar in milk products).

Additives

Some commercial yogurts contain additives such as sugar, fruit, granola, or honey. Added sugar, artificial sweeteners, or colors may be undesirable for some people.

Nutritional Info

The nutritional makeup of 1 cup of plain yogurt from whole cow's milk includes:

• Calories: 195
• Fat: 11 g
• Sodium: 105 mg
• Carbohydrates: 14 g
• Sugars: 10 g
• Protein: 10 g
• Calcium: 318 mg
• Potassium: 410 mg
• Lactose: 8 g

Health Benefits of Kefir

How kefir benefits health is an active area of study. Most research on kefir is done on mice and rats or in the lab and not on humans. The research is promising, but more is needed to understand how adding kefir to the diet affects human health. The results of preliminary studies include:

• Anticancer effects: Kefir shows anticancer effects on lab-grown cells. It's not yet clear if kefir is a possible preventive or treatment for cancer in humans.
• Anti-inflammatory effects: The effects of kefir on inflammation are seen in animal and lab studies. It reduces the number of pro-inflammatory cells and increases anti-inflammatory cells. Kefir may act on inflammation in the digestive system.
• Antioxidant effects: Free radicals are unstable molecules that occur naturally in the body. Antioxidants are beneficial substances that neutralize free radicals. Kefir acts as an antioxidant in mice and lab studies.
• Cholesterol-lowering effects: In animal studies, kefir lowered cholesterol levels. The microbes in kefir may reduce the amount of cholesterol absorbed in the small intestine.
• Effects on blood sugar levels: There are a few studies of kefir on humans with diabetes. One small study shows kefir decreased fasting blood glucose and HbA1c (two common diabetes blood tests) in people with diabetes. Another study showed that a combination of the drug metformin and kefir decreased fasting blood sugar and HbA1c. Kefir is a low to moderate glycemic index food, meaning it is an appropriate food choice for people with diabetes.
• Gut health: Kefir affects the gut microbiome. An imbalance in the bacterial makeup of the microbiome is called dysbiosis. Dysbiosis is associated with various diseases and conditions. The probiotics in kefir change and improve the content of the gut bacteria.
• Lowering blood pressure: Most studies on kefir affecting blood pressure are on rats, not humans. Rats fed kefir had lowered blood pressure, possibly due to changes in their gut bacteria and other antihypertensive effects of kefir. Studies on kefir itself show it contains substances that may lower blood pressure.
• Protecting against infection: Studies in the lab and on rats show kefir inhibits the growth of certain bacteria, fungi, and viruses. The antimicrobial effects might work in the gut microbiome. Another potential application of kefir is in keeping foods safe from pathogens (disease-causing organisms).

Health Benefits of Yogurt

Yogurt contains probiotics, though fewer strains and CFUs than kefir. The quality of research supporting yogurt's health effects is variable. Potential benefits include:

• Lowering colon cancer risk: Some research shows a reduced risk of colon cancer in people who eat yogurt. Eating a 1 cup serving more than once a week shows the most benefit in reducing certain types of polyps and colon cancer.
• Decreasing the risk of diabetes: One study shows a reduced risk of type 2 diabetes in adults who ate yogurt. This effect was not evident with other dairy products. Both low-fat and full-fat yogurt had the same effect. The researchers think the reduced risk is associated with the probiotics found in yogurt.
• Preventing high blood pressure: A large study shows that regularly eating yogurt lowers the risk of developing high blood pressure (hypertension). Researchers think the benefits are due to yogurt's probiotic and calcium content. People who already have high blood pressure don't see this benefit.
• Antioxidant effects: Yogurt from cow's milk has antioxidant effects. However, they are much lower than those of cow's milk kefir.
• Weight control: Eating yogurt was associated with a lower risk of overweight or obesity in one comparison of studies. The risk decreased by 13% for those who ate about one-half cup of yogurt daily.

Risks and Safety

Drinking kefir and eating yogurt are considered safe for most healthy people, but there are potential risks. Some reasons to be cautious include:

• Allergic reactions in people allergic to cow's milk
• Digestive upset from the high probiotic content, which is managed by increasing the amount slowly
• High sugar content of flavored kefir or yogurt that could raise blood glucose levels
• Infections in immunosuppressed people due to the live bacteria
• A low alcohol content in kefir that may affect people with sensitivities
• Consuming too much calcium, which could lead to health problems such as kidney stones

How to Eat Kefir or Yogurt

Yogurt and kefir are enjoyed alone, as a base for a smoothie, or substituted in recipes that call for milk (such as soups, stews, or baked goods). However, heating yogurt or kefir will likely kill many or all of the beneficial bacteria it contains.

Fruit, granola, honey, or maple syrup are often added to plain yogurt to flavor it. Kefir and yogurt, plain or with fruit or other additives, are readily available in commercial grocery stores.

People interested in the health benefits of yogurt and kefir should check the probiotic content on the label and look out for additives that may not support health.

Summary

Kefir contains more strains and total numbers of bacteria than yogurt. Some commercial yogurts have added probiotic strains. There are no guidelines about the type or amount of probiotics humans should consume for health benefits.

Emerging evidence supports the benefits of kefir and yogurt, but it is largely animal and lab studies. Yogurt and kefir are considered good additions to the diet for most healthy people.