Updated Feb 28, 2019
Kefir (pronounced ‘kuh-feer’) is a cultured or fermented dairy product that originated with shepherds of the North Caucasus region.
They discovered that fresh milk carried in leather pouches would occasionally ferment into an effervescent beverage (because the fresh raw milk was rich in probiotic bacteria and yeasts).
Kefir has long been part of the traditional diets of Russia, Estonia, Latvia, Belarus, Ukraine, Lithuania, and more. Today, it’s trendy as hell.
The natural health and natural medicine world endorse kefir health benefits for its use as a staple in what they see as a healthy diet.
What is kefir?
Kefir is a fermented beverage that traditionally uses cow’s milk or goat’s milk. Any milk would work such as sheep, camel, yak, or buffalo milk.
The grains themselves are not grains in the cereal sense. They are clumpy, grain-like colonies composed of a complex structure of lactic acid bacteria and yeasts.
Because kefir grains are grown in milk, they also contain protein, lipids, and small amounts of sugars.
FUN FACT: Kefir is derived from the Turkish word keyif, which means “feeling good” after eating (1).
How to make kefir
It’s made by adding kefir grains to milk. Over a 24 hour period, microorganisms ferment the naturally-occurring milk sugar, lactose, which produces carbon dioxide or CO2.
This turns the milk into a sour, mildly carbonated beverage with a consistency similar to thin yogurt. The grains are separated from the kefir and can be stored in a small amount of milk, or used immediately to start another batch.
Kefir grains are referred to as the ‘starter culture’.
The taste of kefir is unmistakable; it has an ever so slightly malt flavour with an effervescent feel, not dissimilar to buttermilk.
My introduction to kefir
I attended a kefir workshop hosted by the Toronto chapter of the Weston A Price Foundation where I learned how to make kefir at home using fresh kefir grains.
The grains kinda look like cauliflower or a drier curd cottage cheese. I carefully took my sample home in a small mason jar with a little milk, eager to start to make my own batch.
It’s important to note that kefir grains are live bacteria and yeasts as opposed to the starter kits freeze-dried. Some say the real thing is better. Live kefir grains do make a different product, I’ve used both but they’ll both be a source of healthy microorganisms.
Taking care of kefir grains is easy; simply place them in milk so that they have “food” and are able to grow.
What about store-bought kefir?
If you’re not inclined to make your own kefir, don’t despair! There are plenty of good quality kefirs on the market. You can find them at most grocery stores and health food stores.
One such product (and one I use) is Liberte brand . It contains about 37 billion CFUs per 100 ml (1/4 cup) or 5.5 billion CFUs per 15 ml (1 tablespoon).
Because kefir is made from milk, it will have the same nutrition as milk.
An 8-ounce (250 ml) serving of low-fat kefir contains 104 calories, 9 g protein, 2.5 g fat, 12 g carbohydrate and:
- Calcium 316 mg (29% DV)
- Magnesium 29 mg (12% DV)
- Phosphorus 255 mg (23% DV)
- Potassium 400 mg (15% DV)
- B2 0.4 mg (25% DV)
- B1 0.3 mg (23% DV)
- B12 0.7 mcg (35% DV)
- Vitamin A 1383 IU (41% DV)
- Vitamin D 100 IU (16% DV)
Given it’s fermented with lactic acid bacteria, it will have a bunch of organic acids and bacterial and yeast-derived proteins which have health benefits as well (1).
Is kefir lactose-free?
For people with lactose intolerance, kefir is another option for anyone following a lactose-reduced diet. The fermentation does reduce some of the lactose content but not completely.
The good news, however, is that kefir contains lots of bacteria that aid lactose digestion (2). Even though there’s lactose present, most find they can tolerate it.
Another option is to make kefir using lactose-free milk which you can buy at the store. If you’re using something like goat or sheep’s milk, which will be harder to find in the lactose-free version, treat it first with lactase drops.
What, or who, is living in that clump of kefir grains?
Typically kefir grains will contain the following micro-organisms and more, over 60 species! Although there is some variation between batches:
- Lactococcous lactis lactis
- Lactococcous lactis cremoris
- Lactococcous lactis diacetylactis
- Leuconostoc mesenteroides cermoris
- Lactobacillus kefyr thermophilic
- Klyveromyces marxianus marxianus
- Saccaromyces unisporis
- Acetobacter species and Streptococcus species
- and more…..
Kefir made at home would vary greatly in the concentration and type of bacteria and yeast that it contains. These things grow on their own, there’s no standardizing how much of each species is present. The diversity of strains in kefir will, of course, vary (3).
Is kefir good for you? In a word: YES.
It has been studied for a variety of health promoting properties. But to be clear, it doesn’t have the evidence to prevent antibiotic-associated diarrhea. For this reason, I wouldn’t recommended for that specific reason.
Kefir is being researched for its role as a worthwhile addition to your healthy eating efforts! Possible benefits include:
Asthma and allergy: at least in animal models of asthma and allergies, kefir has been shown to reduce the inflammation experienced with these conditions (4, 5)
Cholesterol: kefir and probiotics have been shown to reduce cholesterol. They interact with the gut and gut bacteria and influence energy metabolism and (6).
Blood pressure: kefir may interact with the gut-brain-microbiota axis and give the message to lower blood pressure (7, 8).
Blood sugar control: drinking kefir may help reduce fasting blood sugar levels. Again this is likely due to kefir’s impact on the gut bacteria and how they influence energy metabolism and partitioning (9).
General infections: some research shows that kefir has the potential to be beneficial against gastroenteritis, vaginal infections, and yeast infections (10).
Kefir side effects
As a food, kefir is considered very safe but it’s not without some potential side effects.
Like with cow’s milk, children under the age of 1 year shouldn’t have kefir. After 1 year though kefir is considered safe for children.
Because it’s a fermented food product, introducing a large amount of probiotic bacteria might lead to gas and cramping. As the gut bacteria are positively influenced by all the lactic acid bacteria and yeast found in kefir, this will resolve.
There is a theoretical risk for consuming kefir for those who are immuno-compromised. If you or someone you know has a weakened immune system, always check with your doctor first before adding kefir.
Also, anyone with alcohol use disorder should probably avoid kefir. Because there is a very small, but detectable amount of alcohol in kefir, and due to its malty flavour, it might be a trigger for them.
How much kefir should I drink?
There isn’t a hard number for this question. There’s nothing stopping you from having two, 250 ml (2 cups) servings per day from a dairy/milk nutrition point of view. This would provide about 180 billion CFUs of probiotic bacteria and yeast.
From a probiotic point of view, you can approach kefir as a whole foods-based supplement. It will add milk nutrition, as well as, probiotics. Taking 1/4 to 1/3 cup per day is a typical amount to support overall health.
Kefir vs Yogurt
Kefir and yogurt are both fermented dairy products; therefore, this may lead some to assume that both kefir and yogurt offer the same health benefits.
However, this is not the case as kefir contains many more different types of beneficial bacteria that yogurt does not. Kefir also contains both significantly more bacteria
Yogurt is produced by the action of two specific bacteria: lactobacillus bulgaricus streptococcus thermophilus. Once the milk has been fermented, the amount of live bacteria is negligible.
To make matters worse, food companies will often heat pasteurize the yogurt afterward to extend the shelf life.
Yogurt has not been shown to have any beneficial probiotic effect beyond being an easily digestible dairy food. Other fermented products on the market have far fewer strains and don’t have beneficial yeasts as kefir does.
In short, kefir is a more potent probiotic food than yogurt is.
Kefir vs kombucha
Although kefir and kombucha both contain healthful microbes, kefir is a richer source of lactic acid bacteria.
Kombucha is a fermented tea. It also has probiotic bacteria. It’s made by adding specific strains of bacteria, yeast, and sugar to black or green tea, then allowing it to ferment for about a week (11).
The fermentation process produces acetic acid (also found in vinegar) and several other acidic compounds, trace levels of alcohol, and gases that make it carbonated. There are also a lot of probiotic bacteria (12, 13).
Kombucha will obviously differ in nutrition since it’s made from tea. It won’t have protein, minerals, or vitamins like kefir but does have antioxidants and overall tea nutrition.
Kombucha is potentially more problematic with many potential health problems when not made properly unlike kefir. It may be better to buy in-store products with higher quality standards (12, 15, 16, 17).
How to use kefir
As part of a healthy diet, kefir can be a valuable addition and can be easily incorporated into your daily fare.
Kefir, whether it’s homemade or a good quality store-bought product, can be used almost anywhere you’d use milk:
- On cereal
- Kefir smoothies
- As a beverage straight up in a glass
- Baking [although the heat will kill off most of the bacteria and yeast]
Doug Cook RDN is a Toronto based integrative and functional nutritionist and dietitian with a focus on digestive, gut, and mental health. Follow me on Facebook, Instagram and Twitter.