Dr Mohamad Kamal Harb: General Pediatrician, (Children & Adolescent Doctor), Ragheb Harb University Hospital, Nabatiyeh-Lebanon
The human body’s immune system is so complex, that the scientific community is still trying to unpack it even today. How it functions, what affects it, and what roles it plays in the future prevention of diseases, are all questions yet to be fully answered. The immune system is relatively immature at birth and evolves throughout life as a result of exposure to multiple foreign challenges from childhood to young and mature adulthood, and finally to old age where it declines again. Despite the immune system beginning to mature, for children, they are at risk from many pathogenic viruses, bacteria, fungi, and parasites. Nevertheless, he or she has a good chance of survival in developed countries. Before there was good nutrition, hygiene and comprehensive vaccination, there was a high mortality in infants and young children.
How do we help our child build a strong immune system and how does it protect them for the rest of their lives?
The immune system gradually matures during infancy. Critical early protection against many infectious diseases previously experienced by the mother is given by the passive IgG antibodies which are immune components that fight diseases. They are transferred from the mother through the placenta and in milk while breastfeeding. Once that fades away, young children become more vulnerable to infections, although by then they are better armed with the maturing immune system. The risks are now much reduced by vaccinations, which stimulate protective immune responses in the maturing immune system. Nevertheless, children may still acquire viral, bacterial, and parasitic infections that must be fought off and controlled by natural immune responses. Over time, protection provided by the immune response increases, and young adults suffer fewer infections.
But how can the child build a stronger innate immune system that help them produce strong multiple immune cells to fight the diseases?
It is important to highlight that one of the critically important components that affects one’s immune system development throughout his/her entire lifespan is microbiota. Most of the body’s microbiota lies in the intestine. Commonly referred to as the gut. In fact, the human body harbors trillions of microbial cells whose coordinated actions are believed to be important for human life. Intestinal microbiota is the community of good microbes inhabiting the intestinal tract. It undergoes various changes during the first 2 years of life. The intestinal microbiome help regulate metabolism and immune system development. In recent years, various studies have tried to dissect the composition and functionality of the infant gut microbiome and to explore the distribution across the differences in the infant gut biogeography of the corresponding microbial consortia, including those corresponding to bacteria and viruses. Such analyses have linked certain features of the microbiota, such as reduced diversity, to intestinal illnesses in infants or disease states that occur at later stages of life, including asthma, inflammatory bowel disease, and metabolic disorders. On the other hand, infants and children with abundant microbiota have significantly reduced risk for developing diseases. Therefore, a growing number of studies have reported on how the early human gut microbiota composition/development may affect risk factors related to adult health conditions. This concept has fueled the development of strategies to shape the infant microbiota composition based on various functional food products.
The abundant and diverse components of the human gut microbiota play critical roles in the maintenance of human health by assisting in the breakdown of food substances to liberate nutrients that would otherwise be inaccessible. By promoting body cell growth and reproduction, the gut protects people from the growth of pathogens, and stimulates the immune system. Various studies have established a clear correlation between factors that disrupt the gut microbiota during childhood on one hand and immune and metabolic disorders later in life on the other. Thus, there are increasing experimental data that support long-term health benefits elicited by the infant gut microbiota that also implicate the early human gut microbiota in modulating risk factors related to adult health conditions. This realization has in turn fueled the development of strategies to influence the development, composition, and activities of the infant microbiota by the use of nutraceutical products like probiotics and prebiotics.
A variety of human diseases and other forms of pathology have direct associations with fluctuating levels within the microbiome. These pathologies include chronic periodontitis, Crohn’s disease and other forms of inflammatory bowel disease, irritable bowel syndrome, tropical enteropathy, antibiotic-associated diarrhea, and bacterial vaginosis.
Only a relatively small number of (opportunistic) pathogens are considered to be members of the gut microbiota, residing unperturbed within the enteric host microbiota. They pose a health risk only when the gut ecosystem is disturbed and the gut microbiota homeostasis becomes disrupted. A recent study in 2016 showed that the pattern of development of microbiota is altered in children who are delivered by cesarean section, treated with antibodies, or fed by formula feeding. Antibiotic exposure in children disrupts microbiota and increases risk of obesity, diabetes, inflammatory bowel disease, asthma, and allergies.
To conclude, a strong adult immune system is very much dependent on the health the immune system of the individual in their infancy. Vaccination is key to help fight viruses and bacteria throughout life. In addition, it is very important that the mother realizes how pivotal gut microbiota is for her developing child, and how it might help build a resilient immunity that aids him throughout his life. She can choose to deliver normally and avoid cesarean section, if possible, in order to foster intestinal microbiota’s growth. It is clear that breastmilk is for a flourishing gut microbiota. Parents must also pay attention to the food the child eats because the nutrients, vitamins, and components like prebiotics and probiotics also help regulate immunity (1-4). Taking care of the child’s microbiota directly impacts his or her health and immunity for the rest of their lives.
Aptamil is not the author of this article, as it has been written by Dr Mohamad Kamal Harb who is the owner of the content
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2. Bokulich NA, Chung J, Battaglia T, et al. Antibiotics, birth mode, and diet shape microbiome maturation during early life. Science Translational Medicine; 2016; 8(343).
3. Simon AK, Hollander GA, McMichael A. Evolution of the immune system in humans from infancy to old age. Proc. R. Soc. B; 2015; 282.
4. Relman D. The human microbiome: ecosystem resilience and health. Nutrition Reviews; 2012; 70.