The Application of Potential Biotechnologies to Develop Novel Probiotics Functional Food Products With High Viability for Modulating the Gut Microbiome Among Healthy and Under Stress Subiects

The gastrointestinal tract (GI) is an indispensable organ for any human. In addition to digesting and extracting nutrients from consumed foods, it also houses the largest community of human-associated microbes (called human gut microbiota), plays a role in immune system development and modulation, participates in water and electrolyte balancing, and excretes waste products. Because the human gut is constantly affected by external stimuli and foreign objects via food ingestion, it is not surprising that GI tract diseases, and especially diarrheal disease, are one of the most common causes of human illness. Diarrhea is especially prevalent at younger age, and indeed many young Egyptian children are vulnerable to develop such illness.

Healthy GI tract is the most densely populated human-associated microbial habitat and harbors a highly diverse microbial community. This gut microbiota functions as an essential organ in nutrition, immunity, and physiology of human hosts. Gut microbes are responsible for polysaccharide hydrolysis, vitamin production, immune system stimulation, and modulation of gut motility. While healthy gut microbiome provides protection of the human host against pathogen invasion, microbiota disbalance opens doors for the host to be colonized by intestinal pathogens including viruses, virulent bacteria, and parasites, which all can cause diarrhea. The burden of gut infections is high in Egypt, especially among young children. The vulnerability of these groups to gut infections has been linked previously to the level of hygiene and the integrity of intestinal barrier function, and can also be associated with the prevalence of pathogenic microbes in consumed foods such as poultry. The consumption of contaminated food and water, poor health knowledge, and ineffective infection control programs are contributing considerably to the persistence of enteric infections.

One of the approaches to reduce the prevalence of intestinal infections and resulting diarrhea is to improve overall gut health, by promoting the development of healthy gut microbiota and strengthening gut barrier function. Many dietary components can affect the composition and function of human gut microbiome. Among these, dietary fiber constitutes a variety of polysaccharides that are largely undigested and unabsorbed by humans (who lack enzymes required to break them), but are readily degraded by microbes in the large bowel. Fiber species that are selectively utilized by microbes and provide health benefits to the host are called prebiotics. These prebiotic fibers, such as inulin, selectively promote growth and expansion of beneficial members of our gut community, thus making it harder for pathogens to establish themselves in the gut. Fiber degradation by resident gut microbes also increases the levels of beneficial short chain fatty acids (SCFAs), which were shown to improve gut barrier function and reduce tissue inflammation.