Neutrophil phagocytic function and humoral immune response with reference to ascorbate supplementation in aging humans

Age-associated deficiency of vitamin C contributes to the impaired humoral immune response, which in turn plays a role in the increased risk of illness in old age. Healthy volunteers were given vitamin C supplementation. Neutrophil phagocytic function, complement C₃ concentration, and immunoglobulin status were measured at 30, 60, and 90 days. Neutrophil phagocytic function and levels of serum IgG and IgM and leukocytic ascorbate were considerably lower in the aged humans, but these decreases were attenuated by vitamin C supplementation. The level of IgA was not affected by aging. Improved neutrophil phagocytic function and humoral immune response were associated with increased vitamin C status in the aged population and might well contribute to the decreased risk of disease in the aged.