Abstract: With the current over-exploitation of terrestrial resources, multi-dimensional in-depth utilization of aquatic resources has attracted widespread attention. Blue foods including marine animals and algae supply nutrients to 3.2 billion people around the world. Polysaccharides are an important class of nutritional components in “blue foods”, and have various biological activities such as antitumor, anti-inflammatory, and anti-allergic functions. The exertion of these physiological functions is closely related to their immunomodulatory activities. Therefore, this article reviews recent progress on the classification, composition and immunomodulatory activities of polysaccharides in blue foods with a focus on the regulatory effects of polysaccharides in marine mollusks and seaweeds on innate/adaptive immune responses, the antitumor effects of pro-inflammatory polysaccharides, and their role in immune adjuvants, and the role of anti-inflammatory polysaccharides in autoimmune diseases and inflammation in an effort to enrich the understanding of the different immune effects of marine polysaccharides and to provide theoretical support for the development of immunomodulatory functional foods based on polysaccharides from blue foods.

Key words: blue foods; seaweed polysaccharides; marine animal polysaccharides; immunoregulatory activity