Kefir: Milk Kefir
The Science, Health Benefits, and How to Make It
The Science, Health Benefits, and How to Make It
For the past decade, probiotic supplements and foods have been trending upward in popularity.
The scientific community, health enthusiasts, and popular media all agree that beneficial microbes are an essential ingredient for a healthy body and mind.
Why? Because your body contains an equal number of bacteria as “human” cells, and they occur in practically every area of your body, not just your gut.
Maintaining a healthy microbiome can boost your immune system, improve your digestion and gut health, increase your brainpower, and may even prevent a variety of diseases.
But you don’t have to buy fancy pills, capsules, or designer foods to build up your body’s microscopic allies.
As it turns out, traditional foods like milk kefir are less expensive, healthier, and more effective at delivering “good” bacteria where you need them most.
Scientific research demonstrates 6 major health benefits from drinking traditional milk kefir, with new findings coming out all the time.
Keep reading to learn all the different ways milk kefir can boost your health, how to safely make it at home, and 3 kefir recipes that will put any store-bought kefir to shame.
Traditional milk kefir (pronounced “keh-FEER”) is a fermented dairy beverage made from the milk of cows, goats, or sheep.
Despite the similar-sounding names, milk kefir is different from water kefir, which is also called tibicos.
Milk kefir is fermented at room temperature, usually overnight, by adding probiotic kefir grains to milk. The result is a mildly sour, bubbly, slightly alcoholic (sometimes 1-2% alcohol by volume, but typically much lower) drink.
The amount of grains versus milk and the temperature of the vessel can affect fermentation time. Colder temperatures or fewer grains mean longer fermentation compared to warmer temperatures or more grains.
In some cases, people ferment kefir for longer periods. Generally speaking, the longer you ferment it, the higher the alcohol content and the greater the carbonation.
After fermentation, you can enjoy kefir as-is, make it into a fruit or veggie smoothie, or add other ingredients to enhance the flavour and health benefits.
If you haven’t tried kefir yet, think of it as being somewhat in taste and texture to thin, drinkable yogurt. But compared to the live bacterial cultures that create yogurt, the grains used for making milk kefir are quite complex in nature.
What are Kefir Grains?
Dormant or dry kefir grains resemble grains of rice, while active grains look more like yellow or creamy white cauliflower.
Kefir grains are a type of symbiotic culture. That means they contain lactic acid-producing bacteria and yeast that live and cooperate together in a “matrix” of protective proteins, lipids, and polysaccharides.
Different grains can have very different microbial profiles, but all milk kefir grains contain a lot of Lactobacillus bacteria. That’s why kefir often tastes similar to yogurt.
You can reuse kefir grains by simply changing the milk after each batch. Healthy kefir grains also reproduce over time as you use them, so if you make kefir at home, you’ll end up with extra kefir grains to share with others!
The History of Milk Kefir
The early history of kefir is not well-documented, but various legends exist as to its origins.
According to one story, Caucasian shepherds discovered the effervescent beverage while carrying sheep’s milk in leather bags. According to another, the prophet Mohammed gave the grains to people of the Caucasus as a gift from god.
Milk kefir may have originated in the Caucasus mountains in the Ossetia region that is now disputed between the nation-states of Russia and Georgia, or it may be from another part of Russia or Eastern Europe.
The Venetian explorer Marco Polo wrote about kefir in his 13th-century journal The Travels of Marco Polo, where he called it “kemurs” or “kimmiz”.
While Marco Polo was probably the first European explorer to encounter kefir, it likely dates back well over a thousand years.
The traditional method of making milk kefir, still in use today in parts of Russia, Ossetia, and Eastern Europe, involves hanging airtight bags of goat’s or sheep’s milk made from the animal hide by the door of a home. To keep the milk and grains well-mixed, people strike the bags whenever they pass by.
Even the origin of the modern word “kefir” is mysterious. The first known use in Russian occurred in 1884, but linguists disagree about where the term came from. It may be from Turkic köpür meaning “foam,” Turkish keif for “good feeling,” or Kurdish kef meaning “foam or bubbles”.
Thanks to its delicious taste and proven health benefits, kefir is now popular worldwide.
However, most store-bought kefir isn’t anywhere close to traditional homemade kefir when it comes to health properties
Why is Kefir Good For You?
Milk kefir is nutritious, tasty, and chock-full of “good” bacteria that boost your health.
Kefir has all the vitamins, minerals, essential amino acids, and healthy fats that occur naturally in milk.
During fermentation, however, the microbes within kefir grains break lactose found in milk down into lactic acid. The lactic acid helps preserve kefir and keep it from spoiling, and also makes the drink suitable for people with lactose intolerance.
Bacteria called Propionibacteria convert some of the lactic acid into propionic acid, too, which can help reduce inflammation in your gastrointestinal (GI) tract.
Other bacteria and yeast increase the levels of pyruvic acid, acetic acid, diacetyl, and acetoin, as well as amino acids not found in milk, all of which contribute to the unique flavour and health benefits of kefir.
Properly-made kefir also contains kefiran, a polysaccharide produced exclusively by L. kefiranofaciens.
Kefiran may improve the bioavailability of “good” bacteria within kefir.
In fact, the most remarkable effects of kefir are likely due to its high content of beneficial bacteria as well as kefiran
Which Bacteria Occur in Kefir?
Milk kefir can include some or all of the following probiotic strains.
The concentration of beneficial bacteria in kefir ranges from about 1 million colony-forming units (CFUs) to over 10 billion CFUs per millilitre.
In other words, a one-cup serving of kefir could contain as many as 2.4 trillion CFUs!
Not only that, the bacteria found in freshly-made kefir are guaranteed to be living, as well as far more diverse than most supplements.
Finally, kefir may survive digestion better than commercial freeze-dried probiotic supplements.
Kefir Nutrition Facts
Depending on how you make your kefir--the type of milk, dairy or non-dairy, and how long you ferment it--the macronutrient content can vary quite a bit.
Keep in mind that even if you’re lactose-intolerant, you can probably enjoy milk kefir without any discomfort, because the beneficial bacteria break lactose down into harmless lactic acid.
The following macros apply to a single 8-oz (237 ml) serving of kefir made with grass-fed, raw cow’s milk:
- 150 calories (kcal)
- 8 grams of protein
- 2-4 grams of carbohydrates
- 8 grams of fat
And you also get these healthy compounds and micronutrients (approximate values) from a cup of cow’s milk kefir:
- 8-10 grams of lactic acid
- 900 mg short-chain fatty acids (SCFAs) including butyrate
- 140 mg omega-3 fatty acids
- 125 mg conjugated linoleic acid (CLA)
- 300 mg calcium (30% of the United States DietaryReference Intake)
- 600 mg potassium (13% of US DRI)
- 400 mg phosphorus (80% of US DRI)
- 30 mg magnesium (8% of US DRI)
- 100 ug vitamin A (11% of US DRI)
- 100 ug vitamin B1 (8% of US DRI)
- 410 ug vitamin B2 (32% of US DRI)
- 825 ug pantothenic acid (17% of US DRI)
- 220 ug B6 (17% of US DRI)
- 12 ug vitamin K (10% of US DRI)
While the basic nutrition facts of kefir are quite impressive by themselves, the real value of kefir lies in its probiotic nature.
Keep reading to learn how drinking milk kefir daily is one of the best things you can do for your health and wellness!
6 Health Benefits of Milk Kefir
- Decreased Inflammation and Faster Healing
- Improved Digestion and Better Gut Health
- Antimicrobial Activity
- Balanced Neurotransmitters and Enhanced Brain Function
- A Healthier Heart and Cardiovascular System
- Faster Metabolism and Easier Weight Loss
#1 Decreased Inflammation and Faster Healing
Drinking milk kefir may reduce chronic inflammation and help your body heal faster.
Human and animal studies show promising results in the following areas:
- Reducing or preventing cancer, including breast and colon cancers
- Faster healing of wounds or burns when applied topically
- Improved recovery after exercise
- Reductions in fatigue during physical activity
- Anti-allergy and anti-asthma effects
- Treatment of peptic ulcers
According to research, the anti-inflammatory and healing effects of kefir occur for several distinct reasons.
First of all, full-fat dairy kefir is rich in SCFAs like butyrate, as well as SCFA-producing bacteria, which have anti-inflammatory effects.The polysaccharide kefiran has also shown protective and healing properties in studies.
Drinking kefir may shift your immune function from a Th1-dominant to a Th2-dominant state. In other words, when you have too many active T-helper 1 immune cells, you’re more likely to have autoimmune issues, but kefir appears to correct these imbalances and help your immune system work properly.
Some Lactobacilli in kefir may also have antioxidant effects and produce peptides that aid healing.
Lactic acid bacteria can help your body’s immune system kill tumour cells more efficiently, too.
#2 Improved Digestion and Better Gut Health
It’s no secret that probiotics are good for your gut health.
Your GI tract has the highest concentration of bacteria in your entire body, but if you don’t have enough beneficial bacteria, you’re more likely to experience digestive problems, autoimmune issues, and even mental health problems.
Regularly consuming kefir improves your gut bacteria as well as beneficial fungi, which scientists have linked to the following health benefits:
- Better blood glucose control
- Restoring the gut lining and gut junctions to heal “leaky gut”
- Reversing lactose intolerance
- Relief from chronic constipation
- Treating acute diarrhea
- Preventing diarrhea during C. difficile infection
- Reducing antibiotic-associated diarrhea and preserving the microbiome during antibiotic use
- Improvements in irritable bowel syndrome (IBS) and inflammatory bowel diseases (IBD) like Crohn’s disease and ulcerative colitis
And even if you aren’t dealing with gut issues, kefir can still help your body metabolize and synthesize vitamins and nutrients more effectively.
According to a 2018 paper published in Frontiers in Microbiology, regularly consuming probiotics may increase your production of vitamin K and vitamin B12 by boosting levels of beneficial bacteria.
#3 Antimicrobial Activity
Not surprisingly, the “friendly” bacteria in kefir can fight off harmful pathogenic bacteria.
That’s one reason fermented foods are popular in traditional societies: they keep longer without spoiling.
But it turns out that drinking milk kefir can also help eliminate “bad” bacteria that are already living in your body or that you may consume if you accidentally eat spoiled food.
Amazingly, research indicates that a normal serving of kefir fares well in comparison to prescription-strength antibiotics, with “antimicrobial activity equal to ampicillin, azithromycin, ceftriaxone, amoxicillin, and ketoconazole against many [harmful] species”.
It may also help reverse colonization by the harmful microbe H. pylori.
Scientists aren’t entirely sure of all the reasons kefir works so well in this regard, but they do know the probiotic strains work together with kefiran to provide resistance against colonization, eliminate bad bacteria that are already present, and diminish the harmful effects of pathogenic microbes.
#4 Balanced Neurotransmitters and Enhanced Brain Function
Recently, quite a few studies have shown that your gut health plays an integral role in your brain health.
Gut bacteria are involved in immune signalling, the production of neurotransmitters, and other processes that alter the function of your neurons.
The “gut-brain axis,” as it’s called, involves two-way communication between your gut and brain. It’s inconceivably complex, with at least 1 quadrillion (1,000,000,000,000) independent connections between the 100 billion neurons in your brain and 500 million neurons in your gut, each of which has 10,000 synapses (connection points).
Scientists think that gut dysbiosis, which is an overgrowth of harmful bacteria, maybe one culprit behind poor mental health.
Not only that, it appears that a healthy brain actually contains beneficial bacteria!
It’s easy to connect the dots once you realize how important a healthy microbiome is for proper brain function. Because of kefir’s probiotic, gut-health-promoting, and antimicrobial effects, it makes perfect sense that it may benefit your sense of wellbeing and mental health.
These properties may also extend outside of the brain into your central nervous system (CNS). According to a 2015 study in rats, kefir was neuroprotective in spinal injuries.
The short-chain fatty acids found in kefir and produced by bacteria in kefir also have potent pain-reducing effects, and could even help treat degenerative CNS disorders.
According to a study published in Food Microbiology, some lactic-acid bacteria found in kefir can make GABA, a calming neurotransmitter.
GABA production may be the reason that human studies show promising results for using probiotics to treat depression, anxiety, and symptoms of autism spectrum disorder.
Last but not least, evidence in humans also suggests that probiotic strains in kefir may improve function in areas of the brain involved in emotional processing and attention.
#5 A Healthier Heart and Cardiovascular System
Kefir and other probiotics may help you maintain better heart health by favourably altering direct and indirect risk factors for heart disease.
These risk factors include high cholesterol, high blood pressure, blood glucose, and obesity.
According to a 2018 review published in Cellular Physiology and Biochemistry, milk kefir, in particular, may work through the following pathways:
- Recruitment of endothelial progenitor cells
- Improvement of the balance of the vagal and sympathetic nervous system
- Diminution of excessive generation of reactive oxygen species
- Angiotensin-converting enzyme (ACE) inhibition
- Changes in the anti-inflammatory cytokines profile
- Alteration of the intestinal microbiota
While human evidence is still sparse at the moment, animal studies confirm that kefir can reduce blood pressure, restore normal parasympathetic nervous system balance, and even speed up recovery after a heart attack.
#6 Faster Metabolism and Easier Weight Loss
Obesity isn’t just a matter of eating too much.
Gut dysbiosis is more prevalent among overweight people, and numerous studies show that obese people usually have different types of gut bacteria compared to people with normal body weight
These findings also extend to pairs of twins where one twin is obese and the other is lean, demonstrating that obesity is not a purely genetic issue.
Along with restoring healthy gut bacteria, kefir consumption can increase the production of propionic acid, which has anti-obesity and other beneficial metabolic effects.
The authors of a 2015 study also concluded that kefir “can be useful as a complementary or adjuvant therapy in the treatment of diabetes” by promoting healthy blood sugar levels.
And in animal studies, kefir has been shown to alleviate obesity, prevent excess fat accumulation, and decrease fat deposits.
Along with all of its amazing health benefits, one of the greatest things about milk kefir is that it’s easy and inexpensive to make your own world-class kefir at home.
There are three main ways to start your own kefir culture:
While all of these methods work, using healthy live grains is the best way to begin making kefir. Live grains are easier than other methods, and you can obtain all the benefits of kefir starting with your very first batch.
Dried grains work, too, but at first, the kefir won’t be quite as rich in healthy probiotic bacteria.
With dried grains, you may need to replace the milk several times in a row before dried grains begin producing. But over time, as your grains begin to come to life, they’ll enrich themselves and become more diverse in beneficial bacteria.
Direct starter cultures aren’t grains. A direct starter culture is a powder that you can use to make a single batch of kefir, but they usually aren’t reusable, lack many of the probiotics found in kefir grains, and may not provide the equivalent health benefits.
Supplies for Making Milk Kefir
To produce homemade kefir you’ll need the following supplies along with your grains or starter culture:
- A non-reactive container (preferably glass, food-grade ceramic, food-grade stainless steel or food-grade plastic)
- Milk of your choice (ideally organic, grass-fed, and full-fat, or even raw and unpasteurised)
- A room that’s between 65o - 82oF (18o - 28oC)
- About 24 hours
While kefir grains can survive and produce a drinkable beverage between about 39°F and 86°F (4C°-30°C), they’ll have a better chance of survival and your final product will be better if you don’t let it get too hot or cold.
How to Make Milk Kefir at Home
Follow these steps to make your own milk kefir:
1. Clean the vessel first, then rinse it thoroughly.
2. Add the milk, then dump the grains in and agitate them gently with a wooden spoon or other non-reactive utensils.
3. If possible, agitate the mixture whenever you can, or every few hours.
4. After 24 hours, check the milk. If it’s noticeably thickened or bubbly, your kefir is ready.
5. Strain the grains out with a non-reactive strainer or sieve.
6. Enjoy the kefir as-is, incorporate it into a recipe, or chill it in the fridge before drinking.
7. Once you strain the mixture, it’s best to immediately start another batch of kefir to keep your grains healthy.
If you’d rather not make more kefir just yet, add milk to the grains, then refrigerate the mixture until you’re ready.
When it comes to making kefir, there are very few rules. After you make your first batch or two, you can experiment with the ratios, duration, and other variables.
Keep in mind traditional kefir was made by hanging a rawhide bag from a doorway and thumping it, so you really don’t need to be meticulous to succeed at making your own!
Here are some helpful tips to consider:
- A grain-to-milk ratio of about one-to-five up to about one-by-fifteen by volume works well in cooler temperatures.
- In hotter temperatures, a ratio of one-to-twenty up to one-by-sixty by volume can work just fine.
- Indirect light (or a dim cupboard) is better than direct light because sunlight can heat your mixture excessively and may promote other bacterial growth.
- Using an airtight lid will increase the carbonation and slightly boost the alcohol content of kefir, but be careful to use sturdy containers to avoid any “kefir explosions”!
- A cloth or breathable lid works well to keep debris out of the mixture. If you still want carbonated kefir, try bottling it when it’s ready, then storing it in the fridge for a few days.
- Kefir doesn’t really expire--if you store it in the fridge, as long as it smells all right, it should be fine to drink.
According to a 2013 study, kefir grains produce more kefiran around 77°F (25°C) and stirred at a rate of 80 RPM until straining.
If you’re detail-oriented and have a lab-grade stirring machine, feel free to be highly technical about it, but your kefir is bound to be delicious and healthy either way.
It’s almost impossible to fail at making kefir, let alone make it unsafe.
However, there are a few things to keep in mind to ensure your kefir is safe to drink.
Be very selective in terms of the container you use. The acidic and fatty nature of kefir means it can leach metals and other compounds, so make sure you don’t use non-food-grade ceramics, for instance, which may contain harmful substances.
And while it’s unlikely that unwelcome bacteria will colonize your kefir batch, make sure to use the “sniff test” before you drink up.
Dormant grains, excessive heat, or contamination can lead to other species growing, so if your kefir smells “off,” don’t consume it.
How to Care for Kefir Grains
Caring for your kefir grains isn’t complicated, either:
- Don’t forget about them
- Make sure they have enough milk
Pretty simple, right?
If you forget about your grains and leave your kefir for too long, it may still be drinkable, but the grains will essentially be starving.
Most likely, you’ll be able to rehabilitate them by straining, apologizing, and adding more milk. Overall, kefir grains are resilient and very forgiving.
Also, the healthier your kefir grains are, the faster they’ll reproduce.
That means if you keep using the same ratio of grains to milk, you’ll have more grains competing for the same amount of lactose and other nutrients.
This issue is easy to solve. You can either add more milk (resulting in bigger batches), give some grains away, or discard some of the grains.
If you decide to discard grains, it’s best to get rid of the older grains. You’ll be able to identify them because they’ll be darker-coloured and may not float as well.
What about going on vacation?
That’s easy too: just add more milk than usual to your grains, then store the vessel in a cold corner of your fridge. Because cold slows down the fermentation process, your grains won’t run out of lactose or other nutrients for weeks or even months.
3 Kefir Recipes
These recipes are easy, and you can make them using your very first batch of homemade kefir if you like.
If you’re a little more experienced, though, you can also try a second fermentation with these ingredients. To do that, strain your kefir batch like normal, then blend your preferred recipe below (without the grains).
Next, leave the blended mixture out for 2-12 hours to ferment longer, then chill before serving.
Note: a second fermentation isn’t necessary, but it’s a fun way to explore the fermentation properties of kefir with added ingredients.
Tart Berry Kefir
If you appreciate the tangy taste of milk kefir, you’ll love this recipe. The zesty ingredients add more tart bite, making for a delightfully mouth-puckering yet refreshing drink. For best results, use bubbly kefir (see “Kefir Tips” section, above).
Yield: 20 ounces (591 ml) (makes two servings)
- 14 ounces (473 ml) homemade milk kefir, chilled
- 1Juice of one small lemon, fresh-squeezed
- 13/4 cup of frozen organic blueberries
- 1Optional: stevia to taste
1. Combine ingredients in a blender.
2. Cover and blend on medium or high until smooth.
3. Serve immediately.
Creamy Strawberry-Mango Kefir
This recipe is perfect for anyone who enjoys the rich, creamy texture of kefir but would prefer a bit less bite.
Yield: 20 ounces (591 ml) (makes two servings)
- Approximately 10 ounces (354 ml) homemade milk kefir, chilled
- One medium mango
- 1/2 to 3/4 cup fresh or frozen organic strawberries
- 1/4 to 1/2 cup grass-fed heavy cream or 2 tbsp MCT oil
- Optional: stevia to taste
1. Wash, peel, de-pit, and dice mango.
2. Wash, de-stem, and dice strawberries.
3. Combine ingredients in a blender.
4. Cover and blend on low or medium until smooth.
5. Serve immediately.
Creamy or Hard Homemade Kefir Cheese
When kefir grains are healthy and reproducing abundantly, this cheese is an excellent way to preserve and enjoy your extra yield if you’ve been adding more milk to your batches.
Creamy kefir cheese can be used in place of regular cream cheese, while hard kefir cheese with added salt makes a fantastic parmesan substitute.
Serve your kefir cheese raw or cook with it--it’s up to you.
Yield: 4-8 ounces of cheese, plus 6-12 ounces of drinkable whey
- 10-20 ounces or more of room-temperature kefir
- Medium glass or plastic bowl
- Strainer and coffee filter
For hard cheese only:
- Butter muslin or cheesecloth
- Medium colander
- Dinner plate
- Optional: sea salt to taste
1. Place a coffee filter in the strainer, then position on top of the bowl
2. Add sea salt to kefir and stir (optional).
3. Pour your kefir into the coffee filter and let it sit overnight.
4. In the morning, you’ll find creamy kefir cheese in the filter, and drinkable liquid whey in the bowl.
5. Remove the coffee filter carefully by folding edges inward, then transfer to a glass or plastic storage container.
6. Alternatively, to make hard cheese, transfer soft cheese to cloth or muslin, place in a colander over a bowl, put a dinner plate on top, and weigh down with canned foods or other heavy items.
7. For a hard cheese, increase weight for 12-24 hours or until dripping stops.
What About Vegan or Non-Dairy Kefir?
For most people, dairy kefir is the best option.
However, if you’re vegan or have a severe casein allergy (as opposed to lactose intolerance), milk kefir may not work for you.
Non-dairy kefir is a bit trickier to make than milk kefir, and there are no guarantees.
Unlike regular kefir, vegan kefir won’t thicken, and your grains may not survive very long (or they may--again, no guarantees). But it’s still worth a try!
You can use homemade almond milk, plain organic almond milk with minimal additives, coconut milk, or coconut water.
As with milk kefir, experimentation is key, but you can start with a ratio of one-to-six by volume (grains to liquid). Unlike milk kefir, you’ll need to add sugar to almond milk or coconut milk. The best choice is coconut sugar, but plain organic table sugar will do in a pinch.
Coconut water should work fine to make vegan kefir without added sugar, but you can also try adding sugar if plain coconut water isn’t working for your grains.
When you’re ready to begin, pour the liquid into a suitable vessel, add your grains, and cover with a breathable lid.
Stir the mixture any time it separates.
Typical times for non-dairy kefir fermentation are between 24-48 hours. When you notice some bubbles, it’s probably ready.
As always, use the “sniff test” before drinking.
If you aren’t averse to buying animal products without consuming them, making a batch of milk kefir once in a while can help your grains survive longer, even if you don’t drink it.
Conclusion: Drink Kefir Daily for Better Health!
Milk kefir is for everyone. Babies, toddlers, schoolchildren, sick people, healthy people, and athletes can all benefit from drinking kefir regularly.
Even if you have lactose intolerance, kefir should be perfectly suitable for you. In fact, it may enable you to consume lactose without discomfort!
Evidence for the benefits of kefir in humans and animals is promising, and there’s no doubt that more health-promoting effects will be discovered in the near future.
However, there’s no need to wait for more proof--you can discover the health benefits for yourself, easily and inexpensively at home.
Did this article inspire you to try milk kefir for the first time? Have you made vegan kefir successfully? Do you have a favourite recipe you’d like to share?
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