Author
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WU, DAYONG - TUFTS-HNRCA |
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MEYDANI, SIMIN - TUFTS-HNRCA |
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MEYDANI, MOHSEN - TUFTS-HNRCA |
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HUTH, PETER - KRAFT/GENERAL FOODS |
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NICOLOSI, ROBERT - UNIV. MASS., LOWELL |
Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/17/1995 Publication Date: N/A Citation: N/A Interpretive Summary: The effect of polyunsaturated fatty acids (PUFAs), present in several types of cooking oils, on immune function in monkeys was studied. The animals were fed a normal diet for 14 weeks. Thereafter, half the monkeys were fed diets enriched in moderate and then high amounts of fish- derived (e.g., sardine oil) PUFAs while the other half ate diets enriched in moderate, then high plant-derived PUFAs (e.g., palm, soy, safflower oils). Immune function was improved in animals fed the fish-derived PUFA diets. Blood levels of vitamin E, which has been shown to enhance immune response but is impaired by high levels of fatty acids in the blood, were decreased in animals fed plant-derived PUFAs. When vitamin E levels were kept constant, fish-derived PUFAs enhanced immune function. The lack of improvement of immune function by plant-derived PUFAs may be due to differences in their fatty acid composition and effect on vitamin E levels. Technical Abstract: The effect of marine- and plant-derived (n-3) polyunsaturated fatty acids (PUFAs) on T cell-mediated immune response was studied in twenty cynomolgus monkeys. After a 14-week baseline diet, 10 animals were fed diets containing 1.3 or 3.5% of energy as eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) while the other 10 were fed diets containing 3.5 or 5.3% of energy as alpha-linolenic acid (ALA) for 2 consecutive 14-week periods. Both diets significantly decreased the percentage of T cells (except 1.3% EPA + DHA), T-helper cells (except 1.3% EPA + DHA and 3.5% ALA) and T-suppressor cells. Proliferative response of lymphocytes to T cell mitogens significantly increased after 3.3% EPA + DHA diet (p<0.05). IL-2 production significantly increased after 1.3% and 3.5% EPA + DHA diets. No significant change in mitogenic response and IL-2 production was found after ALA diets. Feeding 1.3 or 3.3% EPA + DHA diet significantly suppressed PGE2 production in response to T cell mitogens (P<0.01). A significant decrease in PGE2 production was also observed after 5.3% ALA diet. No significant change in plasma tocopherol level was observed in monkeys fed EPA + DHA diets while a significant decrease was observed in monkeys fed ALA diets. We conclude that after adjustment of the tocopherol level, marine-derived (n-3) PUFA but not plant-derived (n-3) PUFA increased T cell mediated mitogenic response and IL-2 production. This is most likely due to diet induced quantitative differences in cellular fatty acid composition and, thus, in PGE2 production and tocopherol status. |