What is Milk kefir: definition, pros & cons, milk kefir vs yogurt
What is Milk Kefir: Introduction
Milk kefir is an ancient, probiotic-rich drink obtained through the fermentation of milk using kefir grains.
This potion, which resembles yoghurt, proves that healthy eating is affordable for everyone as it is healthy, safe and inexpensive.
According to the Codex Alimentarius standard, it is defined as a fermented dairy product made with kefir grains, containing a minimum of 2.7% protein, 0.6% lactic acid and a maximum of 10% fat.
However, analysing its etymology, it could simply be defined as a healthy and very pleasant drink, as the word ‘kefir’ derives from the Turkish ‘keyif‘, meaning pleasure or enjoyment. While it is normal to think that this is due to a small percentage of alcohol, as with all fermented foods, in the case of kefir, the term ‘enjoyment’ does not refer to alcohol-induced euphoria, but to a state of health that allows one to enjoy life to the fullest. Milk kefir is an extraordinary panacea — almost an elixir of long (and pleasant) life.
This is why the scientific community is excitedly discovering new benefits to add to its long list of advantages every day.
Now we can answer to the question “What is milk Kefir”; but let’s get to know it a little better, starting with its origins.
The history and origin of milk kefir
Although it has only been available in supermarkets for a few years, it is a traditional drink with a history dating back over 4,000 years(1).
Originally from the mountainous regions of the Caucasus and Mongolia, kefir grains were once passed down through families as heirlooms. This is not surprising when you consider that, in those days, the health of a family line was one of the few things that had immense and tangible value.
But what makes kefir grains so healthy?
Characteristics of milk kefir grains
We cannot claim to have learnt everything about ‘What is Milk Kefir’ if we don’t know what milk kefir grains contain.
Description:
When in perfect health, these small grains resemble cauliflower in that they have irregular contours and are white or beige in colour. They have a diameter ranging from 0.3 to 5 cm.
Composition:
Milk kefir grains are composed of:
- 45.7% mucopolysaccharides;
- 34.3% total protein (27% insoluble, 1.6% soluble and 5.6% free amino acids);
- 12.1% ash;
- 4.4% fat, vitamins B and K, and minerals such as calcium, phosphorus and magnesium(3).
However, behind this schematic description lies an extraordinary world of microorganisms that live in symbiotic association, giving your milk its unique characteristics.
Microbiological composition:
According to the Codex Alimentarius, milk kefir should contain at least 10⁷ colony-forming units (CFU)/ml of microorganisms and at least 10⁴ CFU/ml of yeasts. That’s a lot of probiotics!
Kefir grains are composed of lactic acid bacteria, such as Lactobacillus and Lactococcus, and acetic acid bacteria, such as Acetobacter. They also contain yeasts, such as Kluyveromyces, Saccharomyces and Candida, as well as filamentous fungi, also known as moulds, such as Mycoderma (4).
For those of you who are curious, I will provide more specific information:
The benefits of milk kefir
Both scientific literature and popular knowledge suggest that it is a cure-all.
While kefir certainly lives up to many of these claims, much more research and clinical studies are needed to be absolutely certain. For my part, I have only tried to offer you the benefits mentioned in peer-reviewed articles, which should be more than enough to convince you to consume milk kefir.
So, what makes milk kefir so healthy?
In the article ‘Healthy Bread‘, I explained the benefits of sourdough. Additionally, in my article on homemade thick yogurt, I provided a detailed explanation of the benefits of lactic acid bacteria. In the water kefir guide, I listed the many advantages of its close relative.
Clearly, milk kefir grains contain all these colonies, as well as other various unique microorganisms, and have superior physiological, prophylactic and therapeutic properties to all the other foods mentioned so far.
These effects are mainly associated with the incredibly diverse microbiota of kefir and the bioactive compounds formed during milk fermentation. These include various functional organic acids, hydrogen peroxide, ethanol, bioactive peptides, bacteriocins and exopolysaccharides known as kefiran. Acting alone or synergistically, these compounds make kefir a delicious therapeutic food.
Below are all the benefits of kefir:
- Antimicrobial effect: Regular consumption can prevent certain infections, particularly gastrointestinal and vaginal ones, as kefir exhibits significant antimicrobial activity against Salmonella, Shigella, Staphylococcus, Helicobacter pylori, Escherichia coli, Listeria monocytogenes and Candida albicans yeast (6, 7).
- Probiotic properties: The microorganisms present in kefir have immense probiotic potential. This is due not only to the high number of species with probiotic characteristics, but also to their high resistance to the low pH and bile salts found in the gastrointestinal tract and their extraordinary ability to adhere to intestinal mucus(8).
- Antioxidant effect: According to one study, milk kefir is a powerful weapon against oxidative stress thanks to its ability to bind to free radicals and inhibit linoleic acid peroxidation — even more so than vitamin E(9). In this way, kefir can be a valuable aid in reducing DNA damage, which explains its anti-carcinogenic properties(10).
- Anticarcinogenic properties: This important effect is generally attributed to the suppression of tumours in their early stages, the delaying of the enzymatic activities that convert pro-carcinogenic compounds into carcinogens, and the activation of the immune system(11). Therefore, the anti-tumour effect of kefir is systemic, i.e. it acts on distant organs such as the lungs and breasts(12), not just the gastrointestinal tract.
- Anti-inflammatory effect: This may result from the direct action of the kefir microbiota or indirectly through various bioactive compounds, such as bioactive peptides, which activate macrophages, stimulate phagocytosis and cytokine production. This promotes the immune response against chronic diseases such as obesity, diabetes and cancer(13).
- Reduction of lactose intolerance: Due to its lower lactose concentration and high β-galactosidase activity, which breaks down lactose with fewer disturbances, kefir is ideal for those who are lactose intolerant(12).
- Healing effect on wounds and dermatitis: The latest research conducted on animal models has shown that applying kefir cream improves eczema, atopic dermatitis, burns and scar healing(14). This may be due to kefir’s antimicrobial and anti-inflammatory properties acting synergistically to accelerate healing(12).
- Improved mood and sleep: Milk kefir is rich in tryptophan, a precursor of serotonin and melatonin that can help to combat anxiety, depression and sleep disorders(15).
Other benefits of milk kefir
In short, the benefits mentioned so far are enough reason to start including kefir in your diet. However, I would like to mention the following points, even though they are less important than the above benefits:
- Milk kefir is very easy to prepare (here is a complete guide if you want to make it at home).
- It is an inexpensive functional food, especially compared to probiotic foods sold by multinational companies.
- Kefir is a safe food for many people, although not everyone, and the same applies to homemade kefir.
This brings us directly to the contraindications of milk kefir.
Contraindications of milk kefir
Milk kefir is full of health benefits, but it is not suitable for everyone:
- people with milk protein allergies should avoid consuming it;
- those with a weakened immune system or undergoing treatment with immunosuppressants should consult their doctor before consuming it;
- while milk kefir is well tolerated by most people with lactose intolerance, a small percentage may experience side effects. Always consult your doctor first;
- milk kefir contains alcohol, albeit at very low levels. The maximum amount is 0.2–0.5%, whereas beer contains 4% or more and wine contains 10% or more. This makes kefir a food to be careful with for people who are sensitive to alcohol;
- kefir is high in FODMAPs, so if you are on a low FODMAP diet, you should probably avoid it;
- similarly, if you suffer from irritable bowel syndrome (IBS), you should consult your doctor before adding it to your diet;
- furthermore, as milk kefir is a powerful probiotic, it may cause gastrointestinal imbalances during the first few days of consumption, as with all other foods with the same characteristic. However, there is no need to worry as these imbalances will resolve themselves after a few days.
Differences between yogurt and milk kefir
We have examined the question, 'What is milk kefir?', in detail. However, to fully understand its exceptional potential, we will compare it with another ancient and traditional food that has always been considered a panacea for health: yogurt.
Physical and organoleptic differences
If you are used to drinking yogurt rather than eating it, you will find that the physical differences are almost negligible. Both are white and creamy in consistency.
They may also taste similar, as they both have a slightly pungent flavour that varies in intensity.
Microbiological differences
However, if we analyse them from a microbiological point of view, we discover that they are two completely different products. Yogurt contains only two bacterial strains: Lactobacillus and Staphylococcus. Milk kefir contains these two strains as well as acetic bacteria and yeasts, which give it an enormous capacity to resist the acidity of the gastrointestinal tract and make it a powerful probiotic. This incredible microbiota lives symbiotically: one group produces metabolites that serve as sustenance for the other, and vice versa. For this reason, although milk kefir resembles yogurt in appearance and taste, it contains many more bioactive and functional compounds.
Differences in preparation
Another advantage of milk kefir is the simplicity of its preparation. As my guide to making perfect and thick yogurt shows, you first need to heat the milk, wait for it to cool to around 45°C, inoculate it, and leave it to ferment for around 6 hours at a stable temperature of about 45°C. After this, you need to cool it to refrigerator temperature for at least 12 hours. To make excellent milk kefir, simply place the milk kefir grains in cold milk and leave at room temperature for 18–24 hours. It's that simple!
Enjoy the tastiest and most affordable probiotic available, and join the revolution!
Bibliography
1) Farnworth, E (2005) Kefir – a complex probiotic. Food Sci Technol (N Y) 2, 1–17.
2) Marshall VM. Starter cultures for milk fermentation and their characteristics. International Journal of Dairy Technology 1993 may;46(2):52–53.
3) Yaman H, Elmali M, Karadagoglu G, Cetinkaya A. Observations of Ke
fir Grains and Their Structure From Different Geographical Regions: Turkey and Germany; 2006
4) Lopitz-Otsoa, F, Rementeria, A, Elguezabal, N, et al. (2006) Kefir: a symbiotic yeasts–bacteria community with alleged healthy capabilities. Rev Iberoam Micol 23, 67–74
5) Leite, Analy Machado de Oliveira, et al. “Microbiological, technological and therapeutic properties of kefir: a natural probiotic beverage.” Brazilian journal of microbiology 44 (2013): 341-349.
6) Chifiriuc MC, Cioaca AB, Lazar V (2011) In vitro assay of the antimicrobial activity of kephir against bacterial and fungal strains. Anaerobe 17:433-435.
7) Arslan, S (2014) A review: chemical, microbiological and nutritional characteristics of kefir . CyTA J Food 13, 340–345
8) Garrote GL, Abraham AG, De Antoni G (2010) Microbial Interactions in Kefir: A Natural Probiotic Drink. In F. Mozzi, R. R. Raya & G. M. Vignolo (Eds.), Biotechnology of Lactic Acid Bacteria -Novel Applications pp. 327-340
9) Güven, A, Güven, A & Gülmez, M (2003) The effect of kefir on the activities of GSH-Px, GST, CAT, GSH and LPO levels in carbon tetrachloride-induced mice tissues. J Vet Med B Infect Dis Vet Public Health 50, 412–416
10) Nielsen B, Gürakan GC, Ünlü G. Kefir: A Multifaceted Fermented Dairy Product. Probiotics and Antimicrobial Proteins 2014 dec;6(3-4):123–135
11) Liu, JR, Wang, SY, Lin, YY, et al. (2002) Antitumor activity of milk kefir and soy milk kefir in tumor-bearing mice. Nutr Cancer 44, 183–187
12) Rosa DD, Dias MMS, Grześkowiak ŁM, Reis SA, Conceição LL, Peluzio M do CG. Milk kefir: nutritional, microbiological and health benefits. Nutrition Research Reviews. 2017;30(1):82-96.
13) Kubo M, Odani T, Nakamura S, Tokumaru S, Matsuda H (1992) Pharmacological study on kefira fermented milk product in Caucasus. I. On antitumor activity. Yakugaku Zasshi 112:489-495
14) Huseini HF, Rahimzadeh G, Fazeli MR, Mehrazma M, Salehi M (2012) Evaluation of wound healing activities of kefir products. Burns 38:719-723
15) Peluzio, Maria do Carmo Gouveia et al. “Kefir and Intestinal Microbiota Modulation: Implications in Human Health.” Frontiers in nutrition vol. 8 638740. 22 Feb. 2021
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Summary
Article Name
What is Milk kefir: definition, pros & cons, milk kefir vs yogurt
DescriptionWhat is milk kefir? Read this complete guide to learn all about its properties, health benefits and main differences from yogurt
Author
Başak Bartu
