We all know kefir by now. In recent years, in fact, this fermented milk has gone from a niche product to a permanent presence in supermarkets, thanks above all to the fame linked to its live lactic ferments and its possible role in maintaining the balance of the intestinal flora.
But how much truth is there behind this reputation? And above all, is kefir really the best choice if we are looking for a product rich in live microorganisms? To find out, The Lifesaver commissioned the Maurizi Group to carry out a laboratory analysis comparing three very popular products: kefir, Greek yogurt and skyr.
Kefir, Greek yogurt and skyr: the differences
At first glance they may seem to be very similar alternatives, to be consumed for breakfast or as a snack. In reality, kefir, Greek yogurt and skyr arise from different fermentation processes and can have very different microbiological characteristics.
Kefir is obtained by fermenting milk through a complex community of microorganisms. It is precisely this variety of bacteria and yeasts that characterizes it and makes it particularly interesting from a fermentation point of view.
Yogurt, on the other hand, is produced through specific lactic ferments. Greek yogurt is then distinguished by the filtration process which eliminates part of the whey, giving the product its typical creamy and compact consistency.
Finally, skyr is a traditional Icelandic product which, although very reminiscent of yogurt in terms of consistency and method of consumption, is closer to a fresh cheese due to the way in which it is obtained.
In short, three foods that we find in the same refrigerated counter, but which are not at all equivalent when it comes to live cultures.
The test results
The comparison involved 27 samples in total: 9 Greek yogurts, 9 kefirs and 9 skyrs, belonging to three different brands for each category.
The analyzes took into consideration four groups of microorganisms: Streptococcus thermophilus; Lactococcus spp.; Bifidobacterium spp.; Lactobacillus spp.The objective was to understand which and how many live microorganisms were actually present in the different products.
And this is precisely where the surprise emerges. The result shows a very clear difference between the three categories: Greek yogurt and kefir have high quantities of live microorganisms, while in skyr the values detected are decidedly lower.
In yogurt samples the concentration of microorganisms analyzed reaches at least 10 billion cells, while in kefir concentrations of the same order are found for streptococci, lactococci and lactobacilli.
For bifidobacteria, however, a lower concentration is detected in kefir, equal to approximately 10 million cells. The skyr result is even more distant: for bifidobacteria and lactobacilli the values stop around 1000, while the presence of streptococci and lactococci is not detected in the analyzed samples.
The picture that emerges is therefore quite clear: being a fermented product does not necessarily mean having the same quantity or variety of live microorganisms.
How many ferments do we need
But let’s get to the most interesting question: does having many live bacteria necessarily mean obtaining greater benefits? In the test, a quantity of approximately 1 billion live cells per day is indicated as a reference to obtain temporary intestinal colonization by a microbial strain.
Based on the results obtained, this quantity can be achieved by consuming yogurt and kefir, while it is not achieved by skyr in the analyzed samples.
This data, however, does not mean that a jar of kefir automatically guarantees certain health benefits. In fact, the simple presence of live microorganisms is not enough to establish the effect of a food on the organism: the type of microorganism, the strain, the quantity actually consumed and individual characteristics also count.
Even the deadline can make a difference
Then there is a detail of the test that is worth underlining. Samples were analyzed 15 days before expiration. The number of live microorganisms does not necessarily remain constant over time and may decrease as we approach the end of the product’s commercial life.
For those who choose kefir or yogurt precisely for their content of live cultures, therefore, even the moment in which they consume them can have its importance. In general, it is best not to wait unnecessarily for the end of the shelf life.
Is it really worth eating kefir?
The kefir boom did not arise out of nowhere, and indeed significant quantities of live microorganisms were detected in the laboratory comparison. But there is an aspect that is often lost when talking about this food: it does not mean that kefir is superior to yogurt just because it has become the protagonist of a food trend.
In the comparison carried out by The LifesaverIn fact, Greek yogurt showed the best results overall in terms of concentration of the microorganisms analyzed, followed by kefir.
This doesn’t make yogurt an absolute “better” food or make kefir useless. It simply means that, if the criterion we are interested in is the presence of live ferments, both can be interesting, while skyr showed very different characteristics.
And above all, there is no point chasing the most celebrated product as a “probiotic”, a fermented food is not a medicine and the quantity of live bacteria alone does not allow us to predict the health benefits.
Kefir can therefore be a good alternative to yogurt and other fermented milks, especially if we appreciate their taste and texture. But there is no need to consider it an irreplaceable superfood, even the most traditional yogurt can offer a significant quantity of live microorganisms.
