Effect of micronutrient status on natural killer cell immune function in healthy free-living subjects aged >/=90 y.
BACKGROUND
Natural killer (NK) cells play a role in natural immunity against tumor and infected cells. Advanced aging is associated with functional impairment of NK cells and increased susceptibility to nutritional deficiencies.


OBJECTIVE
Our objective was to test whether micronutrient status affects NK cell activity in an older population.


METHODS
The relations between NK cell variables (percentage of leukocytes and cytotoxicity) and blood concentrations of selected micronutrients were studied in 62 healthy, free-living northern Italian subjects (25 men, 37 women) aged 90-106 y. Anthropometric measurements were also made.


RESULTS
All subjects were well nourished according to age-specific anthropometric norms but many of them had micronutrient deficiencies. The prevalence of micronutrient deficiency was highest for selenium (in approximately 50% of both sexes), zinc (in 52% of men and 41% of women), and vitamin B-6 (in 40% of men and 59% of women), followed by vitamin A (in 16% of men and 27% of women) and vitamin E, vitamin B-12, and folate (each in <10% of both sexes). Ubiquinone-10 status was inadequate in 40% of women and 24% of men (P = 0.02). The percentage of NK cells was associated with serum zinc (men: r = 0.573, P = 0. 007; women: r = 0.373, P = 0.031) and selenium (women: r = 0.409, P = 0.018) concentrations. In women only, NK cell cytotoxicity at different effector-target cell ratios was positively associated with plasma vitamin E and ubiquinone-10 concentrations (P < 0.05). No significant associations with NK cell variables were found for the other measured nutrients.


CONCLUSIONS
The results of this study strengthen the hypothesis that individual micronutrients may affect the number and function of NK cells in old age. The study also confirms the high prevalence of micronutrient deficiencies in healthy and apparently well-nourished persons aged >/=90 y.
Ravaglia
G
G
Department of Internal Medicine, Cardioangiology, and Hepatology, the Department of Angiology and Blood Coagulation, and the Division of Geriatric Medicine, University Hospital Sant'Orsola-Malpighi, Bologna, Italy. ravaglia@almadns.unibo.it
Forti
P
P
Maioli
F
F
Bastagli
L
L
Facchini
A
A
Mariani
E
E
Savarino
L
L
Sassi
S
S
Cucinotta
D
D
Lenaz
G
G
D000328:Adult; D000368:Aged / Q000502:physiology*; D000369:Aged, 80 and over; D000886:Anthropometry; D019002:CD56 Antigen / Q000032:analysis; D003067:Coenzymes; D003602:Cytotoxicity, Immunologic; D004032:Diet; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D018655:Lymphocyte Count; D008297:Male; D018977:Micronutrients / Q000032:analysis*; D008875:Middle Aged; D009752:Nutritional Status; D017452:Receptors, IgG / Q000032:analysis; D012643:Selenium / Q000097:blood; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000097:blood; D014810:Vitamin E / Q000097:blood; D015032:Zinc / Q000097:blood
D019002:CD56 Antigen; D003067:Coenzymes; D018977:Micronutrients; D017452:Receptors, IgG; D014451:Ubiquinone; D014810:Vitamin E; C024989:coenzyme Q10; D012643:Selenium; D015032:Zinc