Gut

Probiotics (from the Greek pro bios, meaning “for life”) are microorganisms that colonize the gut and help to maintain its physiological balance, living in symbiosis and having many beneficial effects on the body. Their main effect is to restore the balance of the gut flora, as probiotics combat the spread of pathogens in the gut and strengthen the spread of beneficial microorganisms, the so-called “good bacteria”.

The genus Lactobacillus, for example, is one of the two most common genera that appear on the label of supplements. Some strains of the genus Lactobacillus, such as LGG, LA-5 and L. Shirota, have become widespread all over the world. The second most common genus present in the products on the market is the genus Bifidobacterium, the bacteria of which play a significant protective role as early as in childhood. Also in this case, strains such as BB-12, BB536, W11 and Bl-04 have been of considerable clinical importance, becoming some of the most common names in many products worldwide.

The gastrointestinal tract houses 100,000 billion bacteria. Taken together they are called the gut microbiota, the balance of which is essential for our health. When this bacterial flora becomes altered, the bad bacteria (pathogens) take over from the good bacteria. This condition is called dysbiosis (also known as gut imbalance). To re-balance gut it is important to take food supplements containing several different probiotics strains at the same time, so as to be able to colonize all parts of the gut, thus restoring the natural well-being of the gut flora, a condition known as eubiosis.

How do probiotics work? 

Probiotics promote the well-being of the gut. In fact, they “colonize it”, thus favouring a balanced gut microbiota and supporting the development of the good bacteria at the expense of pathogens.
When dysbiosis occurs, the “bad bacteria” take over. It is therefore important to take probiotics to restore a healthy balance in the gut. Through our diet and food supplements containing probiotics we can restore the presence of “friendly bacteria” that promote a balanced gut flora and our well-being.

How should probiotics be taken?

To maintain a balanced gut, it is useful to take food supplements containing probiotic lactic acid bacteria. Not all lactic acid bacteria can however be defined probiotics. Probiotic properties are strain specific and cannot be extended to other single bacteria, even if they belong to the same genus or the same species.

To be defined a probiotic and taken as a food supplement, the bacterium must satisfy some documented requirements. The main characteristics that it must possess are: 

• Stability: it is important to underline the difference between active probiotic strains and inactive strains that are ineffective because they are destroyed in the stomach. To promote gut well-being, probiotics must be live and active when taken and survive in the acidic environment during their passage into the stomach, so that they reach their site of action, the gut, intact. Probiotics should preferably be taken on an empty stomach to remain active while passing through the stomach.
• Activity: once they have reached their target site, the probiotic lactic acid bacteria for the gut must adhere to the mucosa, colonize it and be capable of multiplying in order to restore the gut balance (eubiosis). Every probiotic strain has specific characteristics and functions, so different strains act in different ways on the human body (the host). These specific properties must be taken into account when choosing which food supplements containing probiotic live lactic acid bacteria to buy.
• Quantity: specific doses of probiotics must be taken to obtain a beneficial effect on the gut. According to the Italian Ministry of Health, the ideal quantity is at least 1 billion live cells per day. However the necessary dose of probiotics varies depending on the strain, which means that different probiotics are effective on the gut in different quantities.
• Efficacy: the live microorganisms, i.e. probiotics, taken must have a beneficial effect on the gut, and thus contribute to the body’s general well-being. The effect of a probiotic must be supported by scientific evidence from efficacy studies in humans. In general, to be effective and restore a balanced gut flora, the probiotic food supplements should be taken for at least 3 or 4 consecutive weeks.
• Safety: it is determined by a lack of side effects on consumers taking probiotics, such as the absence of pathogenicity and virulence, proven in-vitro and in-vivo safety.

Probiotic live lactic acid bacteria are beneficial bacteria that settle in the gut and colonize it, thus helping to maintain a balanced gut flora, a condition known as eubiosis. The lactic acid bacteria feed on prebiotics, nutrients that are obtained from a balanced diet rich in fibre. In cases of intestinal disorders that may have a negative effect on our daily lives, it is advisable to supplement the diet with probiotic live lactic acid bacteria.

Human microbiota is the group of symbiotic microorganisms that live in the human body without causing harm to it. With its weight of 1.5 kg, our microbiota, also called gut flora, is considered a true organ in which 80% of the immune system resides.

Its origin

The gut microbiota is established at birth. During intrauterine life, the gut of the foetus is completely sterile. Its colonization by both good and bad bacteria takes place from the earliest moments of life. The birth canal through which newborn babies pass is full of microorganisms belonging to the mother, which are inevitably transferred to the baby, thus starting the colonization process. Breastfeeding also seems to promote a healthier development of the microbiota, which evolves in time and is gradually completed during a person’s lifetime, up to old age, a period in which changes in the gut flora are more likely to occur.

Why is the gut microbiota so important?

Until recently, the gut flora in adults was believed to have an overall weight of about 1.5 kg. For this reason it is considered a true organ. The matter is however somewhat complex: it can be said that the weight of the gut microbiota of an adult is approximately 200 g. The gastrointestinal tract covers an area as large as a tennis court and is certainly the most heavily colonized organ of the body, housing more than 70% of all the microorganisms that reside in the body, which constitute the gut microbiota. It is here that they perform a series of beneficial functions for the whole body, thus contributing to the delicate gut balance, essential for our health.

Having a balanced gut microbiota thus clearly brings major benefits to our everyday lives: at work, in the family, while practising sport and during travel. Due to the key role that it plays, it is therefore necessary to maintain a state of eubiosis of the bacterial flora through a healthy and active lifestyle, a balanced diet rich in prebiotics that support the good bacteria at the expense of bad bacteria and the consumption of probiotic lactic acid bacteria.

Functions of the gut microbiota

The gut microbiota performs various functions that have a positive impact on the body:

• First of all it has a protective function, by acting as a selective barrier against the proliferation of pathogens: this is the mechanism by which the bacteria that live in the gut remain present thus preventing colonization by other microorganisms eaten or already present.
• The gut microbiota is also important in regulating our immune system, by determining the quantity and quality of the body’s immune response. In fact, the intestinal immune system is stimulated and kept in training by the bacterial flora, which is in turn tolerated by our immune defences.
• The microbiota also allows the production of some of the essential vitamins for the body, such as folic acid, vitamin K and group B vitamins, which takes place in the gut.
• The microorganisms in the gut microbiota also perform an important digestive function, by working ceaselessly to allow the absorption of the nutrients taken in through the diet.
• Another main function of the microbiota is the regulation of intestinal motility or peristalsis, which is also determined by the type of diet. Bacterial flora stimulates the nerve cells in the gut, thus promoting the natural contraction and relaxation of the colon during digestion.

It is therefore essential for the body health to maintain and preserve a state of eubiosis, that is, a balanced gut bacterial flora. On the contrary, a state of dysbiosis of the gut microbiota may have a negative impact on the whole body.

Maintenance of a balanced gut microbiota requires a healthy lifestyle and diet, introducing both probiotics and prebiotics, substances on which probiotics feed and that are naturally present in some foods, such as fibre.

When the gut is healthy, the gut flora is balanced, the various bacteria are present in the right quantities and in all areas of the gut. This kind of situation is called eubiosis (gut balance).

If the gut flora is not perfectly balanced, it may cause disorders such as constipation or diarrhoea.  

This is because the gastrointestinal system is colonized by microorganisms that live in symbiosis with the body. The functioning of the gut has a major effect on our vitality and general well-being.