Short- and long-term beta-carotene supplementation do not influence T cell-mediated immunity in healthy elderly persons.
Supplementation of healthy elderly persons with beta-carotene has been considered a way to enhance immune responses. In study 1 the short-term effect of beta-carotene (90 mg/d for 3 wk) on immunity was assessed in a randomized, double-blind, placebo-controlled longitudinal comparison of healthy elderly women. In study 2 the long-term effect of beta-carotene (50 mg every other day for 10-12 y) on immunity was assessed in a randomized, double-blind, placebo-controlled longitudinal comparison of men enrolled in the Physicians' Health Study. Subjects from both studies taking active supplements had significantly greater plasma beta-carotene concentrations than did subjects taking placebo. The pre- to postintervention change in delayed-type hypersensitivity skin test responses between beta-carotene and placebo groups in the short-term study was not significantly different, nor was the response between treatment groups in the long-term study. There were no significant effects due to beta-carotene supplementation on in vitro lymphocyte proliferation, production of interleukin 2, or production of prostaglandin E2 as a result of short- or long-term beta-carotene supplementation. In addition, there were no differences in the profiles of lymphocyte subsets [total T cells (CD3+), T helper cells (CD4+), T cytotoxic-suppressor cells (CD8+), and B cells (CD19+)] due to short- or long-term beta-carotene supplementation, nor were there differences in percentages of CD16+ natural killer cells or activated lymphocytes (cells expressing interleukin 2 transferrin receptor) due to long-term beta-carotene supplementation. Consistent results from these two trials show that beta-carotene supplementation did not have an enhancing or suppressive effect on T cell-mediated immunity of healthy elderly.
Santos
M S
MS
Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
Leka
L S
LS
Ribaya-Mercado
J D
JD
Russell
R M
RM
Meydani
M
M
Hennekens
C H
CH
Gaziano
J M
JM
Meydani
S N
SN
D000368:Aged; D000369:Aged, 80 and over; D002214:Capsules; D015232:Dinoprostone / Q000032:analysis* / Q000378:metabolism; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007111:Immunity, Cellular / Q000187:drug effects; D007376:Interleukin-2 / Q000032:analysis* / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008137:Longitudinal Studies; D008213:Lymphocyte Activation / Q000187:drug effects* / Q000276:immunology; D016131:Lymphocyte Subsets / Q000145:classification / Q000187:drug effects* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D013997:Time Factors; D019207:beta Carotene / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
D002214:Capsules; D007376:Interleukin-2; D019207:beta Carotene; D015232:Dinoprostone