Emergent Sources of Prebiotics: Seaweeds and Microalgae

Abstract

In recent years, scientists have become aware that human microbiota, in general, and gut microbiota, in particular, play a major role in human health and diseases, such as obesity and diabetes, among others. A large number of evidence has come to light regarding the beneficial effects, either for the host or the gut microbiota, of some foods and food ingredients or biochemical compounds. Among these, the most promising seem to be polysaccharides (PS) or their derivatives, and they include the dietary fibers. Some of these PS can be found in seaweeds and microalgae, some being soluble fibers, such as alginates, fucoidans, carrageenans and exopolysaccharides, that are not fermented, at least not completely, by colonic microbiota. This review gives an overview of the importance of the dietary fibers, as well as the benefits of prebiotics, to human health. The potential of the PS from marine macro- and microalgae to act as prebiotics is discussed, and the different techniques to obtain oligosaccharides from PS are presented. The mechanisms of the benefits of fiber, in general, and the types and benefits of algal fibers in human health are highlighted. The findings of some recent studies that present the potential effects of prebiotics on animal models of algal biomass and their extracts, as well as oligo- and polysaccharides, are presented. In the future, the possibility of using prebiotics to modulate the microbiome, and, consequently, prevent certain human diseases is foreseen.

Keywords: PS; algae; fibre; health benefits; microalgae; microbiota; polysaccharides; prebiotics; seaweeds.

Figure 1

Effects of SCFAs on the expression of several genes, which regulate the production of different proteins and some anti-inflammatory cytokines (colored in green) involved in the immunity status and protection from inflammation. SCFAs also regulate the release of GLP-1, responsible for the increase in the production of insulin and decrease in glucagon (in green), which reduces blood glucose levels. Additional benefits provided by SCFAs are indicated by bold dashed arrows. Specific properties of the main SCFAs (propionate, acetate and butyrate), and the target organs are illustrated as well.