title: Dietary antioxidants: immunity and host defense.
abstract: Natural antioxidants may be defined as molecules that prevent cell damage against free radicals and are critical for maintaining optimum health in both animals and humans. In all living systems, cells require adequate levels of antioxidant defenses in order to avoid the harmful effect of an excessive production of reactive oxygen species (ROS) and to prevent damage to the immune cells. During the inflammatory processes, the activation of phagocytes and/or the action of bacterial products with specific receptors are capable of promoting the assembly of the multicomponent flavoprotein NADPH oxidase, which catalyzes the production of high amounts of the superoxide anion radical (O(2)(-)). Under these particular circumstances, neutrophils and macrophages are recognized to produce superoxide free radicals and H(2)O(2), which are essential for defence against phagocytized or invading microbes. In this state, antioxidants are absolutely necessary to regulate the reactions that release free radicals. Antioxidant nutrients commonly included in the diet such as vitamin E, vitamin C, β-carotene, selenium, copper, iron and zinc improve different immune function exhibiting an important protective role in infections caused by bacteria, viruses or parasites. As a result, dietary antioxidants have been related to modulate the host susceptibility or resistance to infectious pathogens. Overall, numerous studies have suggested that the development of tolerance, and control of inflammation are strongly correlated with specific immune mechanisms that may be altered by an inadequate supply of either macronutrients or micronutrients. Therefore, the present paper will review the effects of dietary antioxidants on immune cell function and the impact on protection against infectious microorganisms.
authors.affiliation: Universidad de Jaén, Facultad de Ciencias Experimentales, Departamento de Ciencias de la Salud, Área de Microbiología, E-23071-Jaén, Spain.
authors.forename: María A
authors.initials: MA
authors.lastname: Puertollano
authors.forename: Elena
authors.initials: E
authors.lastname: Puertollano
authors.forename: Gerardo Álvarez
authors.initials: GÁ
authors.lastname: de Cienfuegos
authors.forename: Manuel A
authors.initials: MA
authors.lastname: de Pablo
mesh_terms: D056704:Adaptive Immunity / Q000187:drug effects*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001424:Bacterial Infections / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D004266:DNA Virus Infections / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism / Q000821:virology; D004032:Diet; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects*; D007249:Inflammation / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D018977:Micronutrients / Q000378:metabolism / Q000494:pharmacology; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology; D018384:Oxidative Stress / Q000187:drug effects; D012327:RNA Virus Infections / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism / Q000821:virology; D017382:Reactive Oxygen Species / Q000009:adverse effects; D014815:Vitamins / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D018977:Micronutrients; D017382:Reactive Oxygen Species; D014815:Vitamins; D019255:NADPH Oxidases