Nutritional supplements can be used to enrich the food with health-promoting substances if these cannot be supplied in sufficient or optimal quantities. Various nutrients are also of crucial importance for the functioning of the immune system. Since the beginning of the COVID-19 pandemic, numerous studies have been published that show a clear connection between the supply of micronutrients and the likelihood of infection and the severity and duration of an illness. As natural substances, micronutrients are particularly suitable for prevention and (complementary) therapy, as they can strengthen the immune system without causing undesirable side effects.