Effects of Probiotics – Expert Dietitian Emel Yılmaz

Effects of probiotics on the immune system

Probiotics are microbial food components that have beneficial effects on the consumer when taken in sufficient amounts. There is a wide variety of probiotic products available on the market. They typically contain several species of lactobacilli and/or bifidobacteria. In this article, I will briefly talk about the beneficial effects of probiotics on our health through their interaction with the immune system.

When we look at the effects of each nutrient on the immune system, we see just how complex our immune system is. Some of the organs, cells and tissues it contains work together to protect us from invading pathogenic microbes. If everything is working properly, the immune response protects us against bacterial infections, viruses, fungi and parasites, cancer cell growth, injury and trauma and gives us an edge. An adequate response to such a variety of potential attacks requires a system capable of effectively eliminating pathogenic microbes without causing unnecessary damage to host tissues.

The functioning of our immune system is so complex that there are no cells or signaling molecules that can be individually measured to determine whether a particular person’s immune system is functioning well or poorly. Indeed, for any measured parameter of immune function, there must be a large variation in a healthy population. This variability is due to our unique genetic and environmental heritage and includes certain factors beyond our control (our age, sex), life events (past exposure to pathogenic microbes, our vaccination history) that determine our ability to respond effectively. Also, there are influential factors such as exercise, smoking, and diet.

Importance of gut microbiota

A significant portion of all of our immune cells have been found to be associated with our gut. This should come as no surprise given the heavy burden our digestive system carries to ensure a rapid and effective response to pathogenic bacteria while remaining tolerant to the wide variety of food antigens it is exposed to throughout the day. . Our digestive system is home to a large ecosystem of common bacteria known as the gut microbiota. We know that the number and type of bacteria we carry in our intestines are affected by our normal diet and also grow throughout our lives. Differences have also been noted when comparing the gut microbiota of healthy individuals with those of individuals with conditions such as type 1 diabetes, allergies and bowel disease.

Strong evidence that we can influence health by manipulating the gut microbiota comes from recent studies using fecal transplants to treat Clostridium difficile infections. This suggests that by modulating the gut microbiota with nutritional interventions such as probiotics, we can ameliorate disease or maintain health. There are several mechanisms by which the application of probiotic bacteria in the diet can affect health. If probiotic bacteria are able to colonize the gut, they can completely inhibit the growth of potentially pathogenic microbes by occupying existing adhesion sites and absorbing available nutrients. The metabolic activity of probiotic bacteria in the breakdown of indigestible carbohydrates leads to the production of short chain fatty acids which acidify the intestinal contents creating an environment which inhibits the further growth of pathogens.

Results supporting the role of probiotics in immune function

Human studies have been used to explore the potential of probiotics to influence a range of health parameters related to the immune system.

It has been found that children diagnosed with an allergic disease are less likely to have bifidobacteria in the stool than non-allergic children. Therefore, studies have been conducted to administer probiotic bacteria to pregnant women and their newborns (especially those at risk for later atopic diseases). They sought to find out if this could have an impact on the incidence of allergic diseases in these children. One of these studies concluded that the administration of probiotics at the end of pregnancy and in the first six months after birth could significantly reduce the incidence of atopic eczema in children. This effect persisted until the age of 4 years, long after the probiotic intervention was stopped. This suggests that early life is a critical period in the development of allergic disease and that targeted interventions during this period may be effective in preventing the onset of symptoms. When it comes to prevention, there is evidence that probiotics can relieve symptoms of pre-existing conditions in children. For example, children recently diagnosed with ulcerative colitis who took probiotics in addition to their usual treatment had a significantly lower incidence of remission or relapse than those who received only conventional treatment. In the elderly, probiotics have been shown to be consistently effective in preventing antibiotic-induced diarrhea. Studies have emerged suggesting that probiotics may also be beneficial in preventing respiratory disease.


Given the above results from human studies, it is inevitable to state that the administration of probiotics is a safe dietary intervention.

I wish you healthy days…

exp. said. Emel Yilmaz

Email: info@emelyyilmaz.com.tr



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