|Han, Sung nim|
Submitted to: Journal of American College of Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/20/2005
Publication Date: 8/7/2006
Citation: Wu, D., Han, S., Meydani, M., Meydani, S.N. 2006. Effect of concomitant consumption of fish oil and vitamin E on T cell mediated function in the elderly: a randomized double-blind trial. Journal of American College of Nutrition. 25(4):300-306. Interpretive Summary: Age-associated change in immune function that causes dysfunction in immune response contributes to higher morbidity and mortality from infectious, neoplastic, and inflammatory diseases in the elderly than in the young. In elderly subjects, vitamin E supplementation was shown to enhance T cell mediated function and to reduce the risk of getting respiratory infections. Several clinical trials have indicated that consumption of fish and fish oil supplements might reduce the risk of cardiovascular and inflammatory diseases. Thus, the elderly are often encouraged to consume more fish or fish oil. However, consuming large amounts of fish or fish oil could interfere with immunity and inflammatory response. The purpose of the study was to determine if concomitant consumption of fish oil and vitamin E would modify the vitamin E level needed for improving T cell function in elderly. A randomized, double-blind study was conducted with 40 healthy male and female elderly subjects (>65 y). All the subjects received 5 g of fish oil daily and a capsule containing different doses of vitamin E (dl-alpha-tocopherol) for 3 mo. The results indicate that consuming vitamin E improves T cell immune function in the elderly, but the changes observed are quantitatively less when elderly subjects consumed fish oil at the same time. Since both fish oil and vitamin E have been shown positive health effects in the elderly, it is important to determine the right dose balance of the two as taken simultaneously so that their synergy will achieve mutual health benefits without nullifying the effect of one against the other.
Technical Abstract: To determine if concomitant consumption of fish oil and vitamin E modifies the vitamin E level needed to improve T cell mediated function in elderly, a randomized, double-blind study was conducted with 40 healthy male and female elderly subjects (>65 y), randomly assigned to one of 4 groups. All 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. The control group (fish oil only) showed no 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 fish oil plus 200 mg vitamin E supplemented group. However, the changes caused by fish oil plus vitamin E in either DTH or PBMC proliferation were not significantly different from the control group’s results. Plasma levels of alpha-tocopherol were significantly increased in all three fish oil plus vitamin E groups. The increase in plasma alpha-tocopherol level was less profound than that previously reported when vitamin E was given alone. The immuno-enhancing effect of vitamin E in the elderly is dampened when concomitantly consumed with fish oil, possibly due to the smaller increase in plasma concentrations of vitamin E in the presence of fish oil.