Influence of a complex micronutrient supplement on the immune status of elderly individuals.

Nutritional status is known to have profound effects on immune function and resistance to infections, particularly in the elderly. We investigated the effect of a complex micronutrient supplement in elderly people on the changes in some of the cellular components of the immune system, on lymphocyte function, and on the antibody response to influenza vaccination. One-hundred-six subjects aged 62 to 98 were randomly assigned to receive a complex micronutrient supplement or a placebo for three months. Subjects were vaccinated against influenza after eight weeks. Clinical parameters, lymphocyte subsets, in vitro lymphocyte activation, and influenza antibody titers were assessed at baseline and after 90 days of supplementation. A significant increase in total lymphocytes (p=0.034) and white blood cells (WBC) (p=0.03) in the supplemented group was observed. A shift from CD4+/CD45RO+ "memory" cells to CD4+/CD45RA+ "naïve" T-cells in favor of CD4+/CD45RA+ "naïve" T-cells took place. The group consuming additional micronutrients showed an increase in CD45RA+ subsets (p=0.032) compared to the control group. A decrease of total cholesterol (from 228.72 + or - 56.11 to 210.74 + or - 52.58, p=0.002) and low-density lipoprotein (LDL) (from 145.75 + or - 48.86 to 125.47 + or - 41.72, p<0.001) was observed. Influenza antibody titers showed no correlation with micronutrient intake. We conclude that supplementation with a complex micronutrient formulation increases the number of various types of immune cells and decreases total cholesterol and LDL in elderly people. No beneficial effect on specific antibody response to influenza vaccination was observed. Further research is needed to evaluate whether enhanced cellular immune responses decrease the incidence of infections in elderly people.