It is recognized that nutrient intake should not only prevent the classic deficiency diseases, but also could reduce illness and improve health. The type of nutrients and the quantity required to achieve such a beneficial effect varies with the index being studied and whether more than one nutrient is being administered simultaneously. For some nutrients, the amounts proposed as being healthful apparently cannot be provided by a reasonable quantity and variety of natural foods. Thus, nutrient supplements may be important for health promotion and prevention of certain chronic diseases.1,2 This view goes against the prevailing dogma in nutritional science that a balanced diet is sufficient to achieve all nutritional objectives.
See also p 1380.
Aging is associated with a reduction in many immune responses in most, but not all, elderly individuals. Changes in immunity associated with aging include decreased delayed hypersensitivity, reduced interleukin 2 production, decreased lymphocyte response to