The ratio of dietary (n-6) to (n-3) fatty acids influences immune system function, eicosanoid metabolism, lipid peroxidation and vitamin E status in aged dogs.
We studied the effects of feeding experimental diets containing (n-6) to (n-3) fatty acid ratios of 31:1, 5.4:1, and 1.4:1 to 20 healthy female geriatric Beagles (9.5-11.5 y) for 8-12 wk on various indices of the immune response. Compared with the 31:1 diet, consumption of the 5.4:1 and 1.4:1 diets significantly increased (n-3) fatty acids in plasma (2.17 +/- 0.64, 9.05 +/- 0.64, 17.46 +/- 0.64 g/100 g fatty acids, respectively, P < 0.0001). Although supplementation with (n-3) fatty acids did not significantly alter the humoral immune response to keyhole limpet hemocyanin (KLH), it significantly suppressed the cell-mediated immune response based on results of a delayed-type hypersensitivity (DTH) skin test. The DTH response after intradermal injection of KLH at 24 h was significantly lower in the group consuming the 1.4:1 diet compared with the group consuming the 5.4:1 (P = 0.02) or the 31:1 diets (P = 0.04), and remained significantly suppressed at 48 h in the group fed 1.4:1 relative to the group fed 31:1. After consumption of the 1.4:1 diet, stimulated mononuclear cells produced 52% less prostaglandin E2 (PGE2) than those from dogs fed the 31:1 diet (224 +/- 74 and 451 +/- 71 pmol/L, respectively, P = 0.04). Plasma concentration of alpha-tocopherol was 20% lower in dogs fed the 1.4:1 diet compared with those fed the 31:1 diet (P = 0.04), and lipid peroxidation was greater in both plasma (P = 0.03) and urine (P = 0.002). These data suggest that although a ratio of dietary (n-6) to (n-3) fatty acids of 1.4:1 depresses the cell-mediated immune response and PGE2 production, it increases lipid peroxidation and lowers vitamin E concentration.
Wander
R C
RC
Department of Nutrition and Food Management, Oregon State University, Corvallis 97331-5103, USA.
Hall
J A
JA
Gradin
J L
JL
Du
S H
SH
Jewell
D E
DE
D000375:Aging / Q000378:metabolism; D000818:Animals; D004041:Dietary Fats / Q000008:administration & dosage*; D015232:Dinoprostone / Q000096:biosynthesis; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D015777:Eicosanoids / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007107:Immune System / Q000187:drug effects*; D015227:Lipid Peroxidation / Q000187:drug effects*; D014810:Vitamin E / Q000378:metabolism*
D004041:Dietary Fats; D015777:Eicosanoids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D014810:Vitamin E; D015232:Dinoprostone