Fucoidan is a complex polysaccharide found in many species of brown seaweed. The brown seaweeds containing fucoidan are widely consumed as part of the normal diet in East Asia, particularly Japan, China, and Korea.
The anti-cancer property of fucoidan has been demonstrated in vivo and in vitro in different types of cancers. Fucoidan mediates its activity through various mechanisms such as induction of cell cycle arrest, apoptosis, and immune system activation. Additional activities of fucoidan have been reported that may be linked to the observed anti-cancer properties and these include induction of inflammation through the immune system, oxidative stress and stem cell mobilization[*]
While more studies are needed to confirm safety and effectiveness, one human study suggests that fucoidan may help to enable longer courses of chemotherapy. Because of its anti-clotting property, fucoidan may increase the side effects of “blood-thinning” drugs.