What makes KING BRITISH® fish foods really unique is ‘Immuno Health Booster’, a natural compound extracted from marine algae. Immuno Health Booster helps provide a natural shield against infection & disease. Immuno Health Booster is an Immuno-modulator, which means that it regulates the immune system producing immunostimulants as well as suppressing them when necessary, helping to avoid auto-immune diseases or allergies.