Fucoidan is a naturally occuring polysaccharide that is readily found in many species of brown algae and brown seaweed such as mozuku, kombu, bladderwrack, wakame, and hijiki. Many of these seaweeds have been a part of East Asian diets, and as such, many East Asian people have reaped the health benefits of Fucoidan. There are a multitude of facets in which Fucoidan is known to aid in human health including cardiovascular and liver health. Interestingly, Fucoidan has been shown by scientists to also help in immune health.
A number of publications have shown Fucoidan can activate vital immune cells (i.e. certain T-cells, NK cells, and dendritic cells) and bolster both innate and adaptive immune systems to help overall immunity and elicit an anti-pathogenic/viral function. Furthermore, Fucoidan has been shown to inhibit a number of viral pathogens such as several strains of the common flu (influenza), measles, and even herpes. One of the mechanisms by which Fucoidan elicits an anti-viral function is by blocking the binding of viral receptors to cells, resulting in reduced infection rates. Fucoidan has also been implicated in anti-pathogenic functions as well. In a preclinical mouse model, Kar and colleagues found that oral administration of Fucoidan lead to a significant reduction in the infection rate of a pathogen of Leishmania (2011, J Antimicrob Chemother). Further studies have shown Fucoidain aids in fighting off many gastrointestinal related pathogens as well (see Digestive and Gastrointestinal Health section). Taken together, Fucoidan has been shown to have a broad immune promoting effect.