Kefir may not be the first thing that comes to mind when looking to boost your immune system. Instead, you might reach for a dose of vitamin C.

However, kefir is a powerful way to support immune function, often rivaling other probiotics’ effectiveness.

“Kefir is packed with probiotics and bioactive compounds that support digestion, reduce inflammation, and fight infections,” Mpho Tshukudu, an integrative and functional nutritionist, told The Epoch Times.

This fermented drink is an easy, everyday option to boost your immune system.

Boost Immune Function

Kefir is packed with probiotics, which help improve the balance of bacteria in the gut and boost the immune system. These beneficial bacteria help the body fight harmful bacteria and viruses more effectively.

Probiotics also influence immune cells, such as T-cells, which are important in defending against infections. Kefir has natural anti-viral and anti-bacterial properties that help prevent infections, Debbie Petitpain, registered dietitian nutritionist, told The Epoch Times.

Traditionally, fermented kefir has been suggested to develop a strong immune system. Introducing kefir early during an infection can strengthen the body’s defenses by supporting the immune system and gut microbiota. This helps boost the immune system in the gut, which plays a key role in fighting infections before they fully manifest.

In addition, the probiotics in kefir can reduce inflammation, which is closely linked to immune system health, and help prevent or manage inflammation-related conditions.

Kefir also supports the production of short-chain fatty acids such as butyrate.

Fatty acids nourish the cells in the gut, strengthen the gut lining, and reduce the risk of leaky gut syndrome, a condition linked to chronic inflammation and autoimmune diseases, Jodi Duval, an Australian-based naturopathic physician and owner of Revital Health, told The Epoch Times.

It can further boost the production of IgA—an antibody that improves the body’s ability to detect and destroy pathogens. The result is a well-regulated immune system that is neither overactive, which can lead to autoimmune conditions, nor underactive, which leaves the body vulnerable to infections, she said.

Kefir Versus Probiotic Supplements

“Kefir provides broader immune system support compared to a single probiotic supplement,” Petitpain said.

Kefir can contain 30 to 60 more strains of beneficial bacteria than many probiotic supplements, according to Tshukudu.

The bacteria in kefir, particularly strains like Lactobacillus and Bifidobacterium, promote the growth of beneficial bacteria in the gut, supporting the gut lining and enhancing the production of anti-inflammatory compounds.

Kefir’s live, active cultures may also be better able to colonize the gut because of their natural protective coating. In contrast, Duval said many probiotic supplements contain freeze-dried strains that may not survive stomach acid as effectively.

In these foods, the natural structure—known as the food matrix—made up of proteins, fats, and other nutrients—acts as natural packaging, helping the probiotics survive digestion and improving their effectiveness in supporting gut health, she said.

If someone has a specific gut imbalance, a targeted probiotic supplement with well-researched strains, such as Lactobacillus rhamnosus GG for antibiotic-associated diarrhea, may be more effective. Ideally, combining both can be beneficial—kefir for daily microbiome support and supplements for specific therapeutic needs, Duval said.

How Much Kefir Should You Drink

For those new to fermented foods, start with 100 milliliters (ml) per day to allow the gut to adjust. Gradually increase to 200–250 ml daily for ongoing gut and immune support. If using kefir for specific benefits, such as post-antibiotic recovery or immune strengthening, 250–500 ml daily can be helpful for a short period. However, consistency matters—small, regular servings are more effective than large, infrequent doses, Duval said.

Who Can Benefit Most From Kefir?

As kefir supports gut health—a key pillar of overall well-being—almost everyone can benefit from it, as many people have some degree of gut imbalance, Tshukudu said.

However, certain groups may find kefir especially helpful. Duval said that those with weakened immunity, recovering from illness, or dealing with frequent infections and chronic conditions may benefit from its immune-boosting properties.

Kefir can also aid digestion and help manage conditions like irritable bowel syndrome and inflammatory bowel disease. Its anti-inflammatory properties help soothe the gut lining, which is often irritated in these conditions.

Kefir also supports microbiome recovery for those taking antibiotics or experiencing diarrhea, Petitpain said.

Microbiome recovery refers to restoring the balance of healthy bacteria in the gut after antibiotics, illness, or other factors have disrupted it.

What You Should Know

While kefir offers many benefits, there are a few things to keep in mind:

Milk allergies and lactose intolerance. People with a milk allergy or severe lactose intolerance should avoid milk kefir, or consult a health care professional before trying it. This group can, however, enjoy water kefir.

Digestive sensitivity. Some people may experience bloating or gas when first introducing kefir. This is usually temporary as the gut adjusts.

Histamine content. As a fermented food, kefir naturally contains histamines, which can be problematic for those with histamine intolerance, Duval said. Histamines may trigger symptoms like headaches, skin rashes, hives, digestive upset, or even more severe reactions such as swelling or difficulty breathing. Such effects are caused by the histamine involved in immune responses, when the body is unable to break it down properly.

Added sugars. Some commercial kefir products contain high levels of added sugar, reducing their health benefits because of weight gain, blood sugar concerns, and chronic low-grade inflammation, which is linked to many chronic conditions. Choose plain, unsweetened versions, or make kefir at home for the best results.

Taste and texture. Kefir has a tangy, slightly sour flavor with a thick, creamy consistency—more intense than yogurt. While some enjoy its taste, others may take time to adjust. Blending it with berries, a dash of cinnamon, or a bit of raw honey can make it more palatable without compromising its benefits. Homemade kefir often has a fresher, more nuanced flavor than store-bought versions, which can sometimes be overly processed or too mild, Duval said.