Milk Kefir and Its Benefits for Gut Health

Although I consume yogurt daily to improve my gut microbiome, until recently, I was not aware of Kefir, a fermented milk drink similar to yogurt made from kefir grains. Recently, a family friend introduced me to this product, prompting me to learn more about it to consider adding it to my daily diet alongside the yogurt I already consume almost daily.

So What’s Kefir?

This ancient product traces its origins to Russia and Eastern European countries, dating back to at least 1884. Kefir, a probiotic-rich beverage naturally fermented from kefir grains, has been enjoyed for centuries. The kefir grains, which resemble tiny cauliflower florets, originated in North Caucasian region, nestled between Europe and Asia. According to legend, they were a gift from the Prophet Muhammad to the local people, who closely guarded their secret. Today, milk kefir’s delightful taste and health benefits have made it a beloved drink worldwide.

Studies are ongoing, but it seems there are many benefits of kefir. Like other foods that contain probiotics (good bacteria) and postbiotics (bacteria byproducts), kefir boosts gut health and provides a number of other health benefits.

– Amber Sommer, RDN, registered Dietician (source: Cleveland Clinic)

In this short Mayo Clinic video, Dr. Joseph Murray, a gastroenterologist at Mayo Clinic, explains probiotics and how they work.

If you’re interested in dig deeper into milk kefir, here are a few selected publications to follow:

  • Leite, A. M. O., et al. “Microbiological, technological and therapeutic properties of kefir: A natural probiotic beverage.” Brazilian Journal of Microbiology 44.2 (2013): 341-349.
  • Guzel-Seydim, Z. B., et al. “A comparison of milk kefir and water kefir: Physical, chemical, microbiological and functional properties.” Trends Food Sci. & Tech 113: 42-43.
  • Sarkar, S. “Microbiological and technological aspects of kefir production.” International Journal of Dairy Technology 61.3 (2008): 447-452.
  • Bourrie, B. C., Willing, B. P., & Cotter, P. D. “The microbiota and health promoting characteristics of the fermented beverage kefir.” Frontiers in microbiology 7 (2016): 647.
  • Rosa, D. D., Dias, M. M. S., Grześkowiak, Ł. M., Reis, S. A., Conceição, L. L., & Peluzio, M. C. G. “Milk kefir: nutritional, microbiological and health benefits.” Nutrition Research Reviews 30.1 (2017): 82-96.
  • Prado, M. R., et al. “Milk kefir: composition, microbial cultures, biological activities, and related products.” Frontiers in Microbiology 6 (2015): 1177.

Where to Find Kefir?

You can find kefir in most grocery stores alongside yogurt and other dairy products. It’s also available at health food stores, farmers’ markets where dairy products are sold, and online retailers like Amazon. Look out for different types such as milk kefir, water kefir, and non-dairy options made from coconut milk.

How to Prepare Kefir?

Kefir can be stored for short or long term, and maintained its quality and freshness. For short-term storage, keep kefir in the refrigerator, ideally in a sealed container to preserve its flavor and probiotic content. For longer storage, consider freezing kefir in ice cube trays and transferring the frozen cubes into a freezer-safe container. This method allows you to thaw only what you need for smoothies or recipes, extending the shelf life while retaining its beneficial properties.

Preparation: Step-by-Step Procedure

Kefir, a milk product, can be made at home to maintain a continuous supply of this nutritious, probiotic-rich beverage for daily or occasional consumption. The Mayo Clinic video provides a short overview of how kefir is prepared.

Below is a step-by-step procedure for growing and preparing milk kefir for consumption:

  • Acquire Kefir grains: Obtain a small amount of kefir grains from a reliable source.
  • Prepare the Jar: Thoroughly clean a glass jar to ensure it’s free of contaminants.
  • Add Milk: Pour fresh milk into the jar at a ratio of about 1-2 tablespoons of kefir grains per cup of milk.
  • Add Kefir Grains: Place the kefir grains into the milk and gently stir with a plastic or wooden spoon.
  • Cover the Jar: Use a breathable cloth or paper towel to cover the jar and secure it with a rubber band. This allows air to flow in while preventing contaminants from entering.
  • Fermentation: Leave the jar at room temperature (between 65-85°F or 18-29°C) for 24-48 hours, depending on the ambient temperature and your taste preference. Warmer temperatures speed up fermentation.
  • Check Consistency: After 24 hours, taste the kefir for its desired thickness and tanginess. If you prefer a more tart flavor, ferment for up to 48 hours.
  • Strain the Kefir: Once ready, strain the kefir through a plastic or non-metallic strainer into a clean bowl. Use a plastic or wooden spoon to assist in straining.
  • Separate the Grains: The kefir grains will remain in the strainer. Transfer them to a new batch of fresh milk to restart the fermentation process.
  • Store the Kefir: Refrigerate the strained kefir in a sealed container. It will keep for about a week.
  • Repeat the Process: Continue making kefir daily or as needed. Over time, kefir grains will multiply, allowing you to share them or make larger batches.

Some tips for preparing kefir:

  • Avoid using metal utensils or containers, as they can react with the kefir grains.
  • If you need to take a break, store the grains in a small amount of milk in the refrigerator. They will go dormant and can be reactivated by returning to room temperature and adding fresh milk.

How to Store Kefir Grains?

Kefir grains can be stored short- or long-term. Following is step-by-step procedure for short-term storage:

  • Gently rinse the kefir grains with cool, non-chlorinated water to remove any milk residue. Use a fine-mesh strainer for this process.
  • Choose a clean glass jar or container with a tight-fitting lid. Avoid metal containers as they can react with the grains.
  • Place the rinsed kefir grains into the prepared container.
  • Pour fresh milk over the grains, ensuring they are fully submerged. For short-term storage (up to 1 week), use about 1-2 cups of milk per tablespoon of grains.
  • Close the container with a lid to protect the grains from contamination.
  • Store the container in the refrigerator. The cold temperature slows down fermentation, keeping the grains viable for up to a week.
  • Periodically check the grains to ensure they remain submerged in milk. Add more milk if necessary.

For Long-term Storage

  • Use Dehydration or Freezing: For storage beyond a week, consider dehydrating the grains or freezing them:
    • Dehydration: Spread the grains on a clean, dry cloth and let them air dry for 2-3 days. Once dried, store them in a sealed plastic bag in a cool, dark place.
    • Freezing: Place the rinsed grains in a sealed plastic bag with a small amount of powdered milk to protect them. Store the bag in the freezer.

Reactivate the Grains

  • To reactivate stored grains, rinse them and place them in fresh milk at room temperature. It may take a few cycles of fermentation to fully restore their activity.

Yogurt vs Kefir: Health Benefit Comparison

Both yogurt and kefir are fermented milk products that contain probiotic microbacteria.

Probiotic Content

Yogurt: Traditional yogurt is fermented with specific bacterial strains, primarily Lactobacillus bulgaricus and Streptococcus thermophilus. Some varieties also contain additional probiotics like Lactobacillus acidophilus and Bifidobacterium bifidum. These beneficial bacteria are known to aid digestion, improve lactose digestion, and boost the immune system.

Kefir: Kefir is fermented using kefir grains, which are a symbiotic culture of bacteria and yeasts (SCOBY). Kefir typically contains a much broader spectrum of probiotics, often including more than 30 strains of bacteria and yeasts such as Lactobacillus kefiranofaciens, Bifidobacterium, Acetobacter, and Saccharomyces. This diversity potentially offers more comprehensive benefits for gut health, including enhanced microbial diversity and more robust immune support.

Digestive Health

Yogurt: The probiotics in yogurt help maintain a healthy balance of gut bacteria, which can improve digestion and alleviate symptoms of lactose intolerance by breaking down lactose. Regular consumption can help reduce bloating, constipation, and other digestive issues.

Kefir: Kefir’s diverse microbial profile may offer superior digestive benefits. The presence of yeasts and a broader range of bacteria can help in breaking down food substances more effectively. Kefir also contains bioactive peptides that have anti-inflammatory properties, potentially aiding in the management of inflammatory bowel diseases.

Immune Support

Yogurt: The probiotics in yogurt can enhance the body’s immune response by stimulating the production of antibodies and enhancing the activity of immune cells such as macrophages and T-lymphocytes.

Kefir: Kefir goes a step further with its immune-boosting properties. Its diverse probiotics, coupled with the presence of bioactive compounds like kefiran, have been shown to have antimicrobial and anti-inflammatory effects. This can further enhance the body’s defense mechanisms against infections and diseases.

Nutritional Profile

Yogurt: Yogurt is an excellent source of calcium, protein, and vitamins B2 and B12. It supports bone health, muscle repair, and energy metabolism.

Kefir: In addition to providing similar nutrients as yogurt, kefir is also rich in vitamin K2, which is crucial for bone health and cardiovascular function. Kefir’s fermentation process breaks down lactose more completely, making it a good option for those with lactose intolerance.

Both yogurt and kefir provide substantial health benefits, particularly for gut health and immune support. If someone already consumes yogurt daily, adding kefir to their diet can introduce a broader spectrum of probiotics and additional health advantages.

How It Differs From Sour Milk?

Sour Milk

Sour milk is typically made by fermenting milk with lactic acid bacteria. This can happen naturally if milk is left out at room temperature, but more commonly, specific bacterial cultures are added to fresh milk to control the process. The primary bacteria used are Lactococcus lactis and Lactobacillus species. These bacteria ferment the lactose (milk sugar) in milk into lactic acid, which thickens the milk and gives it a tangy flavor. Sour milk has a creamy texture and is often used in baking or cooking.

Kefir Milk

Kefir milk, on the other hand, is made using kefir grains, which are a combination of bacteria and yeasts. These grains look like small cauliflower florets and contain a complex mix of Lactobacillus, Lactococcus, Leuconostoc, and Acetobacter species, along with yeasts such as Saccharomyces and Kluyveromyces. The fermentation process in kefir is more complex due to the presence of both bacteria and yeasts, resulting in a slightly carbonated, tangy, and slightly alcoholic beverage with a thicker consistency than sour milk.

Key differences include:

  • Microorganisms: Sour milk is fermented mainly by lactic acid bacteria, while kefir involves a symbiotic culture of bacteria and yeasts.
  • Fermentation Time: Sour milk typically ferments within a few hours to a day, whereas kefir may take a day or more, depending on the temperature and amount of kefir grains used.
  • Nutritional Content: Kefir tends to have more probiotics due to the diverse microbial population, making it more beneficial for digestive health.
  • Flavor and Texture: Sour milk has a mild tanginess and smooth texture, while kefir is tangier, slightly effervescent, and thicker.

Preparing Your Smoothie

When you’re ready for a smoothie, take out the grains and strain them. Use the kefir as your smoothie base, then return the grains to fresh milk and back into the fridge they go.

Milk kefir is versatile and easy to incorporate into a healthy lifestyle, whether consumed alone, added to smoothies, used as a base for salad dressings, or substituted for yogurt or buttermilk in recipes. By integrating kefir into your diet, you can enhance gut health, support the immune system, and enjoy a nutritious, probiotic-rich food.

Acknowledgements: Some sections of the initial draft of this post were generated using ChatGPT-4o.

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