Degree Type

Dissertation

Date of Award

1992

Degree Name

Doctor of Philosophy

Department

Food Science and Human Nutrition

First Advisor

Laura Cook

Second Advisor

Suzanne Hendrich

Abstract

Two experiments were conducted to determine whether increasing dietary linoleate and vitamin E supplementation might interact to improve prostaglandin and lipid status, two indicators of risk for atherosclerosis. The influence of increasing dietary linoleate and d,1-[alpha]-tocopheryl acetate (vitamin E) on platelet fatty acid composition, platelet phospholipase A[subscript]2 activity, lipid peroxidation, vitamin E, aortic 6-keto-prostaglandin F[subscript]1[alpha] (6-keto-PGF[subscript]1[alpha]), serum thromboxane B[subscript]2 (TXB[subscript]2), 6-keto-PGF[subscript]1[alpha], total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride and vitamin E concentrations was studied in 72 weanling male Sprague-Dawley rats. Rats were fed semipurified diets containing 11 or 18% of energy from linoleate (en% linoleate) and graded levels (0, 100 or 5000 ppm) of vitamin E for 10 weeks. Vitamin E status was confirmed by platelet and serum vitamin E levels. Rats fed no vitamin E had the lowest platelet and serum vitamin E concentrations while rats fed 5000 ppm vitamin E had the greatest platelet and serum vitamin E (p < 0.05). Lipid status was verified by platelet fatty acid composition. Platelet C18:1n-9 (oleic acid) was significantly greater in the 11 en% linoleate group than in the 18 en% linoleate group, and platelet C18:2n-6 (linoleic acid) was significantly greater in the 18 en% linoleate group than in the 11 en% linoleate group (p < 0.05). The treatments had no effect on food intake, body weight gain, platelet phospholipase A[subscript]2 activity, aortic 6-keto-PGFi[subscript]1[alpha], serum 6-keto-PGF[subscript]1[alpha], total cholesterol and LDL-cholesterol concentrations. Serum TXB[subscript]2 and platelet lipid peroxidation (TBARS) were significantly greater in the vitamin E-deficient rats than in vitamin E-adequate and vitamin E-supplemented rats (p < 0.05). Serum HDL-cholesterol level was significantly greater in the 100 and 5000 ppm vitamin E-treated rats compared with rats fed no vitamin E (p < 0.05). Serum triglyceride concentration was significantly greater in rats fed 11 en% linoleate compared with rats fed 18 en% linoleate. Increased dietary linoleate may be preventive against heart disease because of its triglyceride-lowering effects. Adequate vitamin E status prevented an increase in serum thromboxane and maintained HDL-cholesterol, two indicators of risk for atherosclerosis. Vitamin E supplementation did not confer a physiological benefit, in terms of the indicators of atherosclerotic risk studied.

DOI

https://doi.org/10.31274/rtd-180813-12178

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Haw-Wen Chen

Language

en

Proquest ID

AAI9234796

File Format

application/pdf

File Size

125 pages

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