1. Discuss the current knowledge on the mechanism of action of prebiotics (dietary fiber) and probiotics in human health and disease. In particular, focus on the role of carbohydrates in their action at the molecular level, including details of relevant structures and processes

Prebiotics are non-digestible short-chain carbohydrates that improves the health of the host by increasing the growth of and activity of beneficial bacteria.

Probiotics means "for life". In other words it is a live microbial feed supplement that affects the host by enhancing its intestinal microbial balance.

Explanation:

Mechanism of Prebiotics in health and disease:

The are responsible for the fermentation in gut micrflora and colon. It improves the health of the host by by reducing the load of pathogenic bacteria by offering better resistance to pathogenic bacterial colonies and by increasing the host mucosal immunity.

In disease condition, it makes our immune system strong by increasing the number of friendly bacteria that fight against the infection.

Mechanism of Probiotics:

It exerts its function by enhancing the epithelial barrier,increasing the adhesion to the intestinal mucosa and in turn inhibiting the bacterial adhesion, exclusion of pathogenic microorganisms from body and modulation of immune system.

Role of carbohydrate:

Studies have shown that consuming carbohydrates , specifically those which are not digested in the upper tract of the gut, plays an important role in enhancing the growth and function of the gut microflora.

Also, carbohydrates such as oligofructose, galacto-oligosaccharides have shown signs of stimulating the growth of lactobacilli and bifidobacteria in the planktonic flora of the colon ( which is a prebiotic effect) and in turn increases the barrier resistance against harmful bacteria.