Effect of concomitant consumption of fish oil and vitamin E on T cell mediated function in the elderly: a randomized double-blind trial.
OBJECTIVE
To determine if concomitant consumption of fish oil and vitamin E would modify the vitamin E level needed for improving T cell mediated function in elderly.


METHODS
A randomized and double-blind study was conducted using 40 healthy male and female elderly subjects (>65 y) who were randomly assigned to one of 4 groups (n = 10/group). All the subjects received 5 g of fish oil daily containing 1.5 g eicosapentaenoic acid (EPA) and 1 g docosahexaenoic acid (DHA), and a capsule containing different doses of dl-alpha-tocopherol (0, 100, 200 or 400 mg/day) for 3 mo. Plasma vitamin E and fatty acid levels, and in vivo [delayed-type hypersensitivity skin response (DTH) and T cell sub-population analysis] and ex vivo [mitogen-stimulated peripheral blood mononuclear cells (PBMC) proliferation and interleukin (IL)-2 production] immune functions were determined at baseline and after supplementation.


RESULTS
The control group (fish oil only) did not show a statistically significant change in either DTH or PBMC proliferation. DTH response, however, was significantly increased from baseline in all groups supplemented with fish oil plus vitamin E and a significant positive correlation between DTH response and plasma concentrations of alpha-tocopherol was observed. PBMC proliferation was only significantly increased in the group supplemented with fish oil plus 200 mg vitamin E. However, the changes caused by fish oil plus vitamin E in either DTH or PBMC proliferation were not significantly different from those observed in control group. Plasma levels of alpha-tocopherol were significantly increased in all three fish oil plus vitamin E groups and the increase in plasma alpha-tocopherol level was less profound than that previously reported when vitamin E was given alone.


CONCLUSIONS
The immuno-enhancing effect of vitamin E in the elderly is dampened when it is concomitantly consumed with fish oil. This may be due to the smaller increase in plasma concentrations of vitamin E in the presence of fish oil.
Wu
Dayong
D
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
Han
Sung Nim
SN
Meydani
Mohsen
M
Meydani
Simin Nikbin
SN
D000368:Aged; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000097:blood; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage* / Q000737:chemistry; D006801:Humans; D006968:Hypersensitivity, Delayed; D007376:Interleukin-2 / Q000096:biosynthesis*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014810:Vitamin E / Q000008:administration & dosage* / Q000097:blood*
D005231:Fatty Acids, Unsaturated; D005395:Fish Oils; D007376:Interleukin-2; D014810:Vitamin E