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Lactic acid bacteria are the oldest microorganisms that originated on the planet at a time when milk did not yet exist. Today, their peacekeeping armies stand to protect our well-being, immunity and optimal weight.
Everyone has heard about the benefits of kefir, yogurt and probiotic products: they are considered one of the main components of a “healthy” diet and are necessary for the prevention of dysbacteriosis. According to the results of research by the State Research Institute of Nutrition of the Russian Academy of Medical Sciences, microbiological imbalance is a widespread phenomenon, dysbacteriosis occurs in approximately 90% of adults and 95% of children.
Lactic acid bacteria are designed to restore the microflora and save us from many diseases. But are all yogurts the same? How do some lacto products differ from others and why do they act so differently on our body? We asked the experts about it.
Why do we need bacteria
According to Academician of the Russian Academy of Medical Sciences Anatoly Vorobyov, Head of the Department of Microbiology, Virology and Immunology of the Moscow Medical Academy. Sechenov, about two kilograms of various bacteria live in the intestines. Even in a healthy person, here you can find the causative agents of a wide variety of diseases. But the development of diseases caused by these bacteria is prevented by bifidobacteria and lactobacilli, which make up more than 90% of the body’s protective microflora.
Lactobacilli provide timely cleansing of the intestines, protect against allergic reactions
A “line of defense” runs through the entire gastrointestinal tract – a layer of beneficial microorganisms that protect against the invasion of toxins and pathogenic microbes. Without these helpers, the body would not be able to fully digest food, absorb vitamins and cope with some other problems.
The most numerous representatives of beneficial microflora are bifidobacteria. They increase immunity, decompose some carcinogens, participate in the synthesis of B vitamins, vitamin K, nicotinic and folic acids, and contribute to better absorption of calcium salts and vitamin D.
Lactobacilli are another group of beneficial microorganisms: they provide timely bowel cleansing and protect against allergic reactions. These microorganisms secrete special substances – lactic and acetic acids, which are poisonous to most pathogenic microbes and create an ideal environment for the intestines to work.
The waste products of these bacteria ensure the maintenance of the desired level of acidity inside the intestine, which, in turn, prevents the reproduction of pathogenic microorganisms. Alas, during life, the number of lacto- and bifidobacteria is gradually reduced under the influence of stress, antibiotics, malnutrition and aging.
The first “live” yogurt
The first attempts to combat dysbacteriosis were made by the Russian microbiologist, Nobel Prize winner Ilya Mechnikov, who used a living culture of bifidobacteria for treatment. Mechnikov’s research interested the physician Isaac Carasso. In his hometown of Thessaloniki, Greece, yogurt was sold in large copper bowls on the streets.
After emigrating to Spain, Carasso ordered from the Pasteur Institute in Paris (it was there that Mechnikov conducted his research) varieties of lactic yogurt cultures – Bulgarian bacillus and thermophilic streptococcus. Using a Balkan yoghurt recipe, in 1919 he started the first industrial production of “live” yoghurts in his small laboratory in Barcelona.
Products Carasso calls the name “Danone” – “little Daniel”, a diminutive of his son’s name. At that time, yogurts were sold in pharmacies by prescription as a remedy. Later they appeared on the general market.
More good… bacteria
Today, products with the prefix “bio” or “probio” can be found on the shelves of almost every store. This means that they contain a probiotic culture – these are certified fermented milk products enriched with living microorganisms, the consumption of which in sufficient quantities is beneficial for human health.
If the favorite of the pioneer of microbiology was the Bulgarian stick, now the heroes of our time are the lactic acid bacteria L-Casei Defensis, Lactobacillus Rhamnosus and Lactobacillus GG, known from advertising. How do they differ from each other and which ones are more useful?
“All these lactobacilli are varieties of the same biological species,” explains Alexei Resnenko, senior researcher at the Endocrinology Research Center of Rosmedtekhnologii. – Any of the major companies involved in probiotics has its own laboratories, where some of the directions are being developed: for some, for example, it is the most tenacious lactobacillus in time, for others it is the most resistant to an alkaline environment. But all these varieties of bacteria bring the same benefit – they stimulate the human immune system.
How does this happen? We drink some product containing lactic acid bacteria. Some of them immediately die in the acidic environment of the stomach, and only a small amount reaches the large intestine, where it remains and is of great benefit. However, the part of the bacteria that died is still good for us.
The cell walls of non-living bacteria also contain substances that stimulate the immune system. Pay attention to the inscriptions on the packaging: the content of bifidobacteria in 1 g of the product must be at least 107 CFU. This means that one gram of the product on the day of expiration must contain at least 107 living cells capable of rapid growth for the reproduction of colonies.
Who’s where
Medicinal lactic products are produced in special laboratories: thanks to gentle processing, they contain a large number of live bacteria and have a short shelf life. “Industrial” biokefirs and yoghurts are produced in dairies. After pasteurization and storage, they lose most of the bacteria.
Yoghurt is a product containing live yoghurt cultures – thermophilic streptococcus and bacillus bulgaris – at a concentration of at least 107 CFU per 1 gram of the product by the expiration date.
Bioyogurt, in addition to live yoghurt cultures, contains probiotic organisms – bifidobacteria or lactobacilli – in an amount of at least 106 CFU per 1 gram of product by the expiration date.
Yoghurt products (thermised) do not contain live bacteria and therefore cannot be considered yoghurts.
Hidden threat
Surely everyone remembers several cases when, due to yogurt eaten on the run, there were problems with the stomach. With what it can be connected?
Firstly, different products are suitable for different people: some with a weak acid formation, others with a strong one.
“People with high acidity are recommended only fresh products containing probiotic cultures, they contain a lot of lactose (milk sugar), which reduces acidity,” explains Alexey Resnenko. – The longer such a product lives in the refrigerator, the less lactose and more various acids it contains. Such products will be good for those who need to normalize intestinal motility.
Previously, in Soviet times, all lactic acid products indicated their acidity, there was a GOST system. Unfortunately, this is not the case now. For example, kefir can have completely different properties depending on the fermentation time. If a pack of kefir is stamped 10.02, and you bought it on 11.02, then it is one-day. It will stand at your house for two days – and it will become a three-day kefir.
It is better for healthy people to alternate different types of lactic acid products from time to time.
One-day kefir is recommended for those suffering from constipation – it helps to cleanse the intestines. But three-day kefir is useful, on the contrary, for those who need to calm the intestines. Low-fat kefir also has diuretic properties, and therefore it is recommended for those who want to lose weight or suffer from edema due to kidney disease.
Another reason for discomfort in the stomach can be a “war of cultures”: different fermented milk products not only contain different types of bacteria, but also have a different acid composition. Eating or drinking several different probiotics at the same time can provoke “internal turmoil.”
For those who have a sensitive stomach or have serious problems (gastritis, dysbacteriosis), it is better to consult a specialist. After examining the results of the tests, the doctor will help you find your “own” product, which is optimal in terms of acidity and microbiological composition. It is better for healthy people from time to time to alternate different types of lactic acid products: kefir, yogurt, fermented baked milk, yogurt.
Yogurt as medicine
Scientists from the University Hospital of Taiwan proposed the use of yogurt containing bifidus and lactobacilli in the treatment of peptic ulcer. They have shown that taking it before a second course of combined treatment significantly improves outcomes. In studies led by Dr. Bo-Chang Cheu, some patients consumed yogurt, while others did not. After repeated treatment, 91% of those who consumed yogurt and 77% of those who did not completely got rid of the ulcer.
Russian specialists from the Institute of Evolutionary Physiology and Biochemistry. Sechenov Russian Academy of Sciences suggested that with the help of lactic acid bacteria it is possible to restore the cells of the nervous system. In the course of the research, undifferentiated cells were used – that is, they have a great growth potential and are capable of forming tissues of any type. They were placed in curdled milk for 20 hours, and then cultivated in a nutrient medium for 30 days.
It turned out that the cells acquired similarities with nerve cells both externally and in biochemical composition. Scientists believe that it is under the influence of lactic acid bacteria that the concentration of calcium ions increases, which play such an active role in the process of cell degeneration.