Food trends are fun, especially when they combine healthy attributes and exotic flavors. The food and beverage industry is innovating at a rapid clip. An interesting subset is the idea of taking something ancient or deeply ethnic and making it mainstream.
For example, ghee, clarified butter, is now available in mainstream supermarkets and in increasingly new flavor profiles. Ghee has been used for millennia in India, where it is a key part of Ayurvedic medicine.
Another example that helps support the body’s microbiota is kefir—a fermented milk beverage cultured from grains. This exotic sounding beverage originated in the region of Eastern Europe and Southwest Asia, and has been a popular beverage in Turkey. In Turkey, the word is known as keyif, which translates to “feeling good” after drinking it.
Kefir grains are a starter culture for the production of the beverages. These grains are not like cereal grains; they are distinctive in their composition—”microorganisms immobilized on a polysaccharide and protein matrix, where several species of bacteria and yeast coexist in symbiotic association.” All this to say that the grains make this drink actively probiotic in nature.
Specifically, according to another published review, Brazilian kefir grains contain numerous homofermentative (resulting in a single end product) lactic acid bacteria (LAB), such as Lactobacillus species L. delbrueckii subsp. bulgaricus, L. helveticus, L. kefiranofaciens subsp. kefiranofaciens, L. kefiranofaciens subsp. kefirgranum and L. acidophilus; Lactococcus spp. Such as L. lactis subsp. lactis and L. lactis subsp. cremoris, as well as heterofermentative (resulting in several or many end products) LAB such as L. kefiri, L. parakefiri, L. fermentum and L. brevis as well as citrate-positive strains of L. lactis.
In order to reach the final product, the kefir grains are blended with milk where the probiotic bacteria in the grains multiply as well as ferment the milk sugars. After about 24 hours of these activities, the result is kefir, which is like a thinner yogurt drink. Oh, and the grains can be reused—which is great sustainability news.
According to the USDA’s FoodData Central, a six-ounce serving of the drink is also a good source of the RDI for several macronutrients—4 grams protein, as well as between 3 and 6 grams of fat and 7 and 8 grams of carbs, depending on the milk source used; and micronutrients such as 15% RDI phosphorus, 10% RDI calcium, 3% RDI magnesium, 10% RDI of B2 (riboflavin) and 12% RDI for B12.
One study noted that consuming kefir (and other probiotic fermented milk products such as yogurt and koumis), have been associated with numerous wide-ranging health benefits such as antimicrobial activity, accelerated wound healing, immune modulation, and cholesterol metabolism, among others.
Kefir grains can reduce the naturally occurring cholesterol levels in milk through fermentation and have been shown to reduce the levels of cholesterol present by between 41% and 84% after 24 hours and 48 hours of fermentation, respectively.
Fermented milks have also been shown in studies to reduce serum cholesterol levels in animal trials. One research team isolated a probiotic strain from kefir to determine how it acted in rats with high cholesterol. Rats fed a diet with kefir—specifically the strain Lactobacillus plantarum MA2—showed significantly lower total serum cholesterol, LDL-cholesterol, triglycerides, liver cholesterol and triglycerides in conjunction with increased cholesterol excretion.
The beneficial bacteria found in typical kefir is robust at fighting off pathogens. This ability is critical for optimal immune function. According to several studies, the probiotics in kefir have been found to exert antimicrobial activity that is equal to that of prescriptions such as ampicillin, azithromycin, ceftriaxone, tetracycline and amoxicillin.
In addition to regulating microbial composition, kefir can favorably modulate the activity of the microbiota. According to researchers, certain Bifidobacterium strains have been shown to exhibit increases in growth rate when cultured in kefir and changes in gene expression have also been observed.
One in-depth study found that kefir contains other beneficial bacteria with antimicrobial properties. For example, the strain L. plantarum ST8KF produces the bacteriocin ST8KF which exerts antimicrobial action against Enterococcus mundtii and Listeria innocua, both of which can cause illness.
The authors of another study write, “Other kefir-derived Lactobacillus species such as L. acidophilus and L. kefiranofaciens, as well as some S. thermophilus strains have shown antimicrobial activity against a whole range of pathogenic organisms including E. coli, L. monocytogenes, S. aureus, S. typhimurium, S. enteritidis, S. flexneri, P. aeruginosa, and Y. enterocolitica .”
In one study investigating kefir-containing compounds on innate immunity, it was concluded that “Different components of kefir have an in vivo role as oral biotherapeutic substances capable of stimulating immune cells of the innate immune system, to down-regulate the Th2 immune phenotype or to promote cell-mediated immune responses against tumours and also against intracellular pathogenic infections.”
This is just some of the published evidence that consuming probiotics in the form of kefir helps protect immune function by proactively inhibiting pathogenic bacteria from taking root.
There’s a unique compound in kefir that is the byproduct of the microbial metabolism, and that has been investigated for its potential human health benefits. Kefiran, specifically described, is the exopolysaccharide made by the bacteria L. kefiranofaciens during fermentation.
One study looked at biological response mechanisms in rodent populations when kefiran was consumed for 30 days. Genetically diabetic mice fed kefiran were found to have decreasing levels of blood glucose throughout 30 days compared to the those in the control group, which exhibited constantly increasing and generally higher levels of blood glucose.
In the same study using SD rats with constipation, it was found that kefiran significantly improved the symptoms of constipation over the control group. The authors asserted that the results “suggest that kefiran could be used as a function food to prevent some commonly occurring” conditions.
Catch Your Kefir
Lifeway® is the pioneering brand of kefir products, once found only in health food stores. It is now popular and mainstream, and has a line of frozen kefirs, which contains 10 live and active probiotic species including L. lactis, L. rahmnosus, L. plantarum, L. casei, L. acidophilus, Streptococcus diacetylactis, Saccharaomyces florentinus, Luconostic cremoris, Bifidobacterium longum and B. breve.
Coyo Organic is a coconut milk kefir suitable for vegans and vegetarians as it is a plant-based kefir. New from kombucha brand GT’s Living Foods is AQUA KEFIR, a new line of sparkling probiotic drinks fermented with non-dairy kefir cultures (it comes in many flavors: peach pineapple, pear ginger, coconut lime and pomegranate) and is fermented with non-dairy kefir cultures.
Oh, and if you are a DIY-er, you can make your own. There are numerous “starter kits” which contain the starter grains and you add either milk, water or other liquid. They are easy to use. And some brands, such as Cultures for Health, include access to a 155-page e-book filled with kefir recipes, and more.
It’s the epitome of the saying, “what’s old is new again” and of course, with a modern twist. Kefir has been consumed regularly in a large portion of the world for hundreds of years, and research has been catching up to not only how it is good for health, but what exactly is in it that is responsible for its physiological attributes. As researchers in one study asserted, “Whole kefir, as well as specific fractions and individual organisms isolated from kefir, provide a multitude of positive effects when consumed.”