The name probiotics refers to living microbes that are a complementary component of human food and have a beneficial effect on their health.
Probiotics are specially selected lactic acid bacteria and bifidobacteria similar to them. A specific feature of probiotic bacteria is their ability to enter into the large intestine, settle in it and reproduce in a living state.
They have a positive effect on the health condition of the digestive tract and, consequently, on the state of our health.
The source of probiotic bacteria is the new generation of fermented milk drinks.
Lactic acid bacteria are widespread in the environment and have been used for natural food acidification since time immemorial. It can be said without exaggeration that these bacteria are found everywhere. From birth, they accompany people, animals and plants. Their common feature is the ability to ferment different sugars, which results in the formation of lactic acid and usually also some other ingredients, some of which have a pleasant nutty aroma. In milk, they ferment lactose, or milk sugar, and in the plant material, glucose or other sugars.
It is thanks to these bacteria that we can sour cucumbers and cabbage, and farmers receive so-called. silage for feeding cattle. Lactic bacteria that accidentally get into milk while milking a cow, acidify it at room temperature after a dozen or so hours.
In the industrial production of dairy products, which uses lactic fermentation, and therefore dairy fermented beverages (yogurt, kefir or regular fermented milk – curds), curds, cheeses, cream and butter obtained from it, you can not rely on accidental (“wild” ) lactic acid bacteria found in raw milk. In the manufacture of these products, specially selected “noble strains of these bacteria are used. They are added to previously pasteurized milk or cream (pasteurization, heating milk or cream for 15-20 seconds, at a temperature of at least 72 ° C to destroy harmful bacteria). Sourdough is increasingly used in the form of dried or frozen bacterial biomass.
In accordance with international and national provisions in the relevant standards, each of the previously mentioned traditional fermented milk beverages should contain the lactic acid bacteria of at least 10 million in 1 cm3.
New generation drinks
New generation drinks are usually obtained by introducing into the traditional beverages fermented additional bacteria that have probiotic features. These are defined strains of different species of bacteria from the genera Lactobacillusi Bifidobacterium. According to the aforementioned findings, the number of probiotic bacteria in such modified beverages should not be lower than 1 million in 1 cm3. With a smaller number, the effectiveness of their beneficial effects on the human body is simply weaker.
In order to easily distinguish traditional beverages from beverages containing additional probiotic bacteria, it is recommended that the latter should have the prefix “Bio. Thus, yogurt produced with the addition of probiotic bacteria is called “Bio-yoghurt, and kefir -” Biokefir (some manufacturers use the same name “Bio”). A certain deviation from this rule is the use of the name “acidified milk – acidophilus in relation to a drink containing a probiotic strain of Lactobacillus acidophilus. The composition of the probiotic microflora should be specified on the unit packaging.
Benefits of microflora
In the digestive tract of a healthy person there is a huge number of bacteria belonging to 400-500 different species. The hydrochloric acid in the stomach and bile acids in the small intestine inhibit the growth of bacteria. Slightly better conditions for their development occur in the final section of the small intestine, but only in the large intestine they reach a huge number of 1 trillion in 1 g of the intestinal content. Intestinal microflora is useful, because it takes part in the digestion of certain nutrients, and at the same time it produces some vitamins, especially vitamins K and B12.
Oral administration of antibiotics causes loss or abnormalities in the composition of the intestinal microflora and may lead to a deficiency of the mentioned vitamins, therefore doctors recommend taking vitamin preparations after a long antibiotic treatment.
Other beneficial effects associated with the presence of intestinal microflora include, for example, participation in the metabolism of bile acids and cholesterol, formation of pathogenic bacteria, stabilization of intestinal mucosa permeability, regulation of proliferation and differentiation of colon (colon) cells, bacteriostatic and bactericidal action against harmful bacteria.
It is worth adding that the factors leading to the disturbance of the intestinal microflora balance include, in addition to the already mentioned antibiotic therapy, also radiation therapy, stress, improper diet and others.
The most important, from the point of view of healthy intestinal microflora, are the different species of lactic acid bacteria from the genus Lactobacillus and of the genus Bifidobacterium (they can be briefly called LB bacteria). Their important function is to counterbalance harmful or potentially harmful bacteria that form an integral part of the intestinal microflora. These include, for example, coliform bacteria or putrid bacteria.
LB bacteria enter the gastrointestinal tract from the environment as early as in the first days of the newborn’s life. It is a very happy coincidence, they ferment lactose contained in mother’s milk, and the lactic acid produced in this way and other specific components inhibit the reproduction of harmful bacteria. It is worth mentioning that breast milk contains factors that stimulate the development of bifidobacteria found in the baby’s digestive tract.
LB bacteria are equally important for adult health. Together with other bacteria, they cover the intestinal epithelium tightly and thus provide a barrier for pathogenic bacteria, dietary antigens and other harmful substances that can be found in the intestine.
With the increased effect of these adverse factors, the stability of said barrier is compromised, in the sense of reducing the number and activity of LB bacteria. As a consequence, intestinal microbiota disturbed in its composition may lead to diarrhea, mucositis and change in its permeability, as well as an increase in the level of carcinogens in the intestinal contents.
Microflora and probiotics
Probiotic bacteria are practically identical to the LB intestinal bacteria. Consumption of new-generation fermented milk beverages means, therefore, an increase in the number of LB-type bacteria in the large intestine, thus strengthening the above-mentioned protective intestinal barrier or restoring its stability, among others through
– adhesion of probiotic bacteria, ie “sticking to the mucosa and, consequently, reducing the chance of adhesion of pathogenic (pathogenic) bacteria,
– inactivation of harmful bacteria, including pathogenic bacteria, thanks to the ability of the probiotic bacteria to produce substances that have an inhibitory or even deadly effect on harmful bacteria (lactic acid, hydrogen peroxide and specific peptides called bacteriocins).
Reducing the number or activity of harmful microflora also means reducing the activity of enzymes produced by it, some of which are thought to have a carcinogenic effect. Research shows that this may lead to a reduction in the risk of colorectal cancer.
It should be noted that adverse changes in the composition of the intestinal microflora worsen with age, which would indicate the desirability of consuming new generation of fermented milk beverages, especially by the elderly.
There is a tendency to enrich fermented milk drinks with some saccharides – the so-called prebiotics (e.g. fructans present in chicory and their derivatives) stimulating the development of intestinal bacteria LB. Drinks containing both probiotics and prebiotics were called synbiotics.
Utilities from plain yogurt
Yoghurt bacteria have limited ability to enter into the large intestine in the living state and therefore they can not be included in the group of sense of probiotic strictobacteria. On the other hand, strictly documented studies were carried out that testify to the probiotic, ie health-promoting properties of yogurt bacteria, and thus plain yogurt. These bacteria could, therefore, be called probiotic-like.
Their pro-health activity is linked to with the ability to significantly alleviate or even eliminate the symptoms of milk lactose intolerance.
Some people have impaired digestion of lactose, resulting in partial or complete loss of intestinal epithelial capacity for the production of lactase enzyme. As a result, drinking normal milk by such people may lead to disorders characterized by flatulence or diarrhea. However, these people may consume moderate amounts of yogurt without the risk of these symptoms appearing.
It is believed that this is related to the presence of lactase enzyme already in yogurt bacteria. This is facilitated by the coagulated form of yoghurt and its consumption, e.g. with bread, because it stays longer in the gastrointestinal tract, thus prolonging the duration of bacterial lactase. Other studies suggest that consumption of yogurt stimulates the body’s immune system. Some studies have also shown the anti-carcinogenic effect of this product.
The benefits of kefir
As for traditional kefir, it also contains microflora, which according to previously accepted criteria does not fit into the concept of probiotic microflora. However, its health-promoting properties, resulting even from the content of bacteriostatic lactic acid, can not be ruled out. Perhaps also from the presence of bacteriocins and protein hydrolysates or other biologically active ingredients that stimulate the body.
It should also be added that all fermented milk drinks, irrespective of the microflora used for their production, are an excellent source of exceptionally well-absorbed calcium and high biological value protein, numerous vitamins and many other ingredients.
Although lactic acid bacteria use some vitamins, they synthesize more, and as a result, the profile of vitamins in milky fermented beverages is usually better than in milk.
The conducted research provides ever new information on the beneficial effects of these products on the human body. It has been found, for example, that as a result of protein hydrolysis, peptides may be formed that inhibit an enzyme that converts a substance called angiotensin into the body, which may contribute to the reduction of renin-dependent arterial hypertension.
– maintaining balance in the native intestinal microflora,
– restoring this balance in case of disturbing factors,
– combating infections and other intestinal disorders.