Global malnutrition (reduced intake or increased requirements for protein and calories) is the most common nutritional deficit in the elderly population. Micronutrients (vitamins and trace minerals) deficiencies are also common in older adults. Malnutrition consequences on immunity are characterized by a decrease in cell mediation immunity with a reduction in naive T cells and in cytokine production. During infection, the treatment must be specific and after infection it has to associate nutritional supplementation and exercise. The lack of clear benefit in the use of specific micronutrient should discourage the use of high-dose supplementation for an immunologic indication.