An algal biomass and supernatant derived from at least one species of algae exhibits the ability to maintain general health in humans and non-human animals and promote a healthy immune system in them. Food, feed and nutritional supplements comprising an algal biomass or supernatant derived from at least one species of algae are described. Methods of maintaining general health or promoting a healthy immune system in humans and non-human animals comprises administering to the animal in need thereof an algal biomass or supernatant derived from at least one species of algae, or an extract, derivative or homeopathic compound derived from the algae species, biomass or supernatant, or a composition thereof.
