Vitamin C and immunity: an assessment of the evidence.

The high concentration of ascorbate in leucocytes and its rapid expenditure during infection and phagocytosis suggests a role for the vitamin in the immune process. Evidence published to date shows an involvement in the migration and phagocytosis by macrophages and leucocytes, as well as the induction and expression of delayed hypersensitivity. Its effect on antibody production and complement levels is controversial but probably minimal. This study suggests there is room for further investigation into the effect of ascorbate on immunity, particularly with defined populations, but cautions the use of megadose therapy.