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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Healthy Body Weight Research » Research » Publications at this Location » Publication #79973
Title: DIETS HIGH IN PHYTOCHEMICALS AND FIBER DECREASE PLASMA CHOLESTEROL OXIATION

Author
item SPILLER, G - SPHERA FOUNDATION
item KUYPERS, F - SPHERA FOUNDATION
item BRUCE, B - SPHERA FOUNDATION
item ROITMAN, E - SPHERA FOUNDATION
item Klevay, Leslie

Submitted to: American Society for Clinical Nutrition
Publication Type: Abstract Only
Publication Acceptance Date: 4/6/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The oxidation of cholesterol involving reactive oxygen species generates a variety of cholesterol oxidation products. Oxysterols may be involved in the etiology of atherosclerosis or cancer. The major oxysterol formed by lipid peroxidation in plasma is 7-oxo-cholesterol, reported to be an index of lipoprotein cholesterol susceptibility to peroxidation. To study the effect of a plant-based diet high in phytochemicals, unsaturated fatty acids and dietary fiber on levels of oxysterols in plasma, 12 hyperlipidemic women consumed first a diet based on refined plant foods and low in fruits and vegetables for 4 weeks (Diet 1), followed by 4 weeks on a diet based on unrefined plant food, high in sun-dried raisins [phenolic compounds (PC) and soluble dietary fiber], nuts, sesame seeds and whole grains [insoluble fiber and alpha and gamma tocopherols], olive oil, green tea (PC) and high carotenoid fruits and vegetables (Diet 2). Calories and total fat intake were similar for both diets, with saturated fat decreasing by 62% on Diet 2, Tocopherols, other phenolics and carotenoids increased 5-fold and vitamin C 1.3 fold on Diet 2. 7-oxo -cholesterol was measured with Gas Chromatography Mass Spectrometry, using deuterium labeled standards. The levels of 7-oxo-cholesterol in the plasma of the study subjects varied between 14.6 and 114 ng/ml. At the end of Diet 2, there was an average reduction of 21% (range -4 to -48%) for 7-oxo-cholesterol as compared to levels on Diet 1. It appears that raisins, nuts, whole grains and other unrefined plant foods affect the level of reactive oxygen species-induced cholesterol oxidation, possibly as the result of an altered stat of defense mechanisms against oxidative damage.