Are fermented drinks good for you? A look at probiotics, benefits, and risks

October 8, 2025 •

4 min read

Fermented foods and drinks have been a part of human diets for millennia, originally used for preservation, but their modern popularity is tied to a renewed focus on gut health. This raises the question: Are fermented drinks good for you, and what does the science say about their purported health benefits and potential drawbacks?.

Quick Summary

Fermented beverages like kombucha and kefir are rich in probiotics, which can benefit gut health and digestion. While offering various nutrients and potential immune-boosting effects, these drinks may also contain added sugars and alcohol, with risks for certain populations.

Key Points

Probiotics for Gut Health: Fermented drinks, like kombucha and kefir, contain beneficial live bacteria and yeasts (probiotics) that can help balance the gut microbiome.
Diverse Nutritional Profiles: These beverages are often rich in nutrients such as B vitamins and organic acids, which result from the fermentation process.
Moderate Your Intake: Most fermented drinks contain trace amounts of alcohol, and many flavored varieties have added sugar; checking labels and moderating consumption is advised.
Listen to Your Body: When first introducing fermented drinks, start with small amounts, as some people may experience temporary digestive discomfort like gas or bloating.
Certain People Should Be Cautious: Individuals with compromised immune systems, histamine intolerance, or those who are pregnant or breastfeeding should consult a doctor before consuming fermented drinks.
Understand the Differences: Kombucha is tea-based and tangy, while kefir can be dairy-based and creamy or water-based and fruity, offering different probiotic profiles and nutrient compositions.

Understanding Fermentation: An Ancient Practice

Fermentation is a natural process driven by microorganisms like bacteria and yeast, which break down carbohydrates—such as sugar and starch—into acids, gases, or alcohol. This process not only preserves food but also creates beneficial compounds and, crucially, probiotics.

Historically, fermentation was a vital method for preserving food before refrigeration. Today, this process is celebrated for its ability to transform simple ingredients into complex, nutrient-rich products. This renewed interest has pushed fermented drinks like kombucha and kefir into the mainstream as health beverages, but it's important to differentiate between products with genuinely beneficial live cultures and those that are heavily processed or high in added sugar.

The Power of Probiotics and the Gut Microbiome

The primary draw of many fermented drinks is their probiotic content—live microorganisms that, when consumed in adequate amounts, can provide a health benefit to the host. A healthy gut microbiome, the complex community of microbes residing in our digestive system, is linked to a host of health benefits, including better digestion, a stronger immune system, and even improved mental health.

How Probiotics Help Your Gut

Restoring balance: Probiotics help to maintain and restore a healthy balance of gut bacteria, especially after disruption from illness or antibiotics.
Improving digestion: They aid in breaking down food and can alleviate common issues like constipation and bloating.
Supporting immunity: The gut houses a significant portion of the body's immune system, and a balanced microbiome is crucial for robust immune function.

Health Benefits of Popular Fermented Drinks

Different fermented drinks offer unique benefits based on their ingredients and specific microbial composition. While many studies support the general health-promoting properties of fermented foods, much of the research is still evolving.

Kombucha: This fizzy, tangy beverage made from fermented sweetened tea is known for its antioxidants, organic acids, and B vitamins. Some research suggests it can aid liver detoxification and help manage blood sugar, though more human studies are needed. Its probiotic profile may also help improve gut health and digestion.
Kefir: A fermented dairy drink, kefir is often considered a more potent probiotic source than yogurt, containing a wider array of bacteria and yeast strains. It is rich in calcium and B vitamins and can be tolerated by many with lactose intolerance, as the fermentation process breaks down much of the lactose. Water-based versions also exist for those who avoid dairy.
Kvass: A traditional Eastern European fermented drink, kvass is often made from fermented rye bread or beets. It offers its own set of probiotics and can be a refreshing, low-alcohol beverage.

Potential Risks and Who Should Be Cautious

While generally safe for most people when consumed in moderation, fermented drinks are not without potential downsides. Awareness of these risks is key to safe consumption.

Potential Issues to Consider:

Alcohol Content: All fermented drinks contain some level of alcohol as a byproduct of fermentation. While typically low (often under 1.15% ABV), unpasteurized or homemade versions can have higher, more variable levels. This is a concern for children, pregnant or breastfeeding women, and those with certain medical conditions or who need to avoid alcohol.
Added Sugar: To appeal to a wider audience, many commercially available fermented drinks add extra sugar or flavorings after fermentation. Always check the nutrition label, as this can significantly increase the calorie and sugar count.
Risk for Vulnerable Groups: Individuals with compromised immune systems, such as those with HIV/AIDS or undergoing chemotherapy, should consult a doctor before consuming fermented drinks, especially unpasteurized or homemade varieties, due to the risk of opportunistic infection from live cultures.
Histamine Intolerance: Some people have trouble breaking down histamines, and fermented foods are high in these compounds. This can lead to allergic-like reactions, including headaches or stomach upset.
Digestive Discomfort: For those new to probiotics, introducing fermented drinks too quickly can cause temporary gas, bloating, or diarrhea as the gut microbiome adjusts. It is best to start with small amounts and increase gradually.

Kombucha vs. Kefir: Which is right for you?


Feature	Kombucha	Kefir
Base	Sweetened black or green tea	Dairy milk, coconut milk, or sugar water
Starter	SCOBY (Symbiotic Culture of Bacteria and Yeast)	Kefir grains (bacteria and yeast clusters)
Probiotic Diversity	Contains a good range of bacteria and yeasts, with a higher concentration of acetic acid bacteria	Generally a more potent and diverse probiotic source, with more strains of bacteria and yeasts
Nutritional Profile	Contains B vitamins, organic acids, and antioxidants from tea	Rich in protein, calcium, phosphorus, B vitamins, and vitamin D (for dairy kefir)
Taste & Texture	Fizzy, tangy, sometimes vinegary; often flavored with fruits	Tangy, creamy (dairy) or lighter and fizzy (water); often thicker than kombucha
Lactose Content	Lactose-free	Very low in lactose, and non-dairy versions are available

Conclusion: Informed Choices for Your Health

Fermented drinks can be a valuable addition to a nutritious diet, offering a convenient way to consume probiotics and other beneficial compounds for gut health. However, their suitability depends on individual health needs, preferences, and proper consumption. By understanding the differences between drinks like kombucha and kefir, being mindful of sugar and alcohol content, and introducing them gradually, you can decide whether they are a good fit for your wellness journey. Always consult a healthcare professional if you have underlying health conditions or concerns.

This article is for informational purposes only and is not a substitute for medical advice. Consult with a qualified healthcare provider for personalized recommendations.

Frequently Asked Questions

The primary benefit of drinking fermented drinks is their probiotic content. These live microorganisms, such as those found in kefir and kombucha, help maintain a healthy balance of bacteria in your gut, which is crucial for digestion and immunity.

Yes, many people with lactose intolerance can tolerate kefir. The fermentation process breaks down much of the lactose into lactic acid, making it easier to digest than regular milk. Non-dairy water kefir is also an excellent option.

Most fermented drinks, including kombucha and kefir, contain a small amount of alcohol as a natural byproduct of fermentation. While generally very low, unpasteurized or homemade versions may have higher, more variable levels.

Kombucha is a fermented tea with a tangy, fizzy taste, while kefir can be a fermented dairy or water-based drink with a creamier or fruitier taste, depending on the base. Kefir is often a more potent probiotic source, with a wider range of microbial strains.

Due to their trace alcohol and caffeine content, pregnant and breastfeeding women are advised to be cautious with fermented drinks. The safest option is often to avoid them or consult with a healthcare provider.

Yes, you can get probiotics from a wide variety of fermented foods, including yogurt, sauerkraut, kimchi, and miso. Consuming a diversity of fermented foods can help promote a healthy gut microbiome.

Possible side effects include temporary gas and bloating, especially when first starting. Individuals with histamine intolerance or a compromised immune system may need to avoid them due to potential allergic reactions or infection risk.