E. ADHDASSI, B. LIU, M. MCARTHUR, A. SIMOR, A. MCGEER, AND J. P. ALLARD. Dept of Medicine, University of Toronto, Toronto, Ont, Canada.

Aging is generally associated with impaired immune responses and nutrition is an important determinant of immunocompetence. In this study, plasma from 83 subjects (43 male and 40 female, age: 80.4± 0.96 y, wt: 66.86± 1.52 kg) living in 5 LTCFs in the Toronto area was analyzed for vitamins C, E, beta-carotene, retinol and zinc. Immunological variables such as IL2 and natural killer cells (NK) number and activity and mitogen responses to phytohenagglutinin (PHA), pokweed (PWM) and conca navalin A (CONA) were also assessed. Subjects with a history of cancer and those taking vitamin or mineral supplements were excluded. Results on plasma micronutrients are reported as mean± SEM in umol/I.

Low plasma level (<lower range of ref value) of beta-carotene, zn, vitamin C, alpha-tocopherol and retinol were seen in 71.4%, 24.3%, 9.2%, 3.8% and 3.8% of the subjects respectively. Results on immunological variables are reported as absolute counts of lymphocytes with IL2 and Nk receptors. The lymphocyte responses to PHA, CONA and PWM are reported in counts/min.

There were 16.2%, 9.5% and 35.3% of the subjects with lower response to PHA, PWM and CONA respectively. There were significant (p<0.05) correlations between plasma beta-carotene and Nk number (r=0.444), beta-carotene and Nk %activity (r=0.477), plasma zinc and lymphocytes response to concanavalin A (r=0.224), plasma zinc and response to phytohemagglutin (r=0.321) and zinc and NK activity (r=0.284). The results of this study indicate that micronutrient deficiencies are common among elderly and it may affect immune function in this population.

Presented at:

AMERICAN COLLEGE OF NUTRITION CONFERENCE, Washington, DC, September 1999.

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