Nutrient intake and immune function of elderly subjects.

OBJECTIVE: Food intake, aging, and immune function share complex influences. Therefore, the purpose of this study was to examine relationships between nutrient intakes from food and dietary supplements and a biomarker of immune function. DESIGN: Data were collected from participants in a cross-sectional study as well as baseline data from a longitudinal study (n=89). Subjects completed 24-hour food recalls, including supplement intake. Polyclonal mitogen phytohemmagluttin (PHA) was the immune function stimulator used. Height and weight were used to calculate body mass index. STATISTICAL ANALYSES PERFORMED: Descriptive, bivariate correlation, Spearman's rho for nonparametric data, t tests, and stepwise regression with nutrient intakes as independent variables and T-cell proliferation as dependent variables. RESULTS: Significant positive correlations (P< or =0.05) were found between PHA-induced proliferation and intake of docosahexaenoic acid (DHA), eicosahexaenoic acid (EPA), sodium, and selenium, although intakes of DHA plus EPA were inadequate when compared to recommended intakes. A significant negative correlation with total vitamin A, with many vitamin A levels being above the upper limit of safety. Regression analyses found these nutrients to be variables significant in explaining the variance in PHA (P=0.005). CONCLUSIONS: Selenium, sodium, DHA, EPA, and vitamin A intake from diet and supplements were associated with PHA-induced proliferative responses. Clients may be counseled to have adequate selenium, EPA, DHA intake, and vitamin A, but avoid excess vitamin A.