High intakes of vegetables, berries, and apples combined with a high intake of linoleic or oleic acid only slightly affect markers of lipid peroxidation and lipoprotein metabolism in healthy subjects.
BACKGROUND
A high consumption of vegetables and fruit is associated with decreased risk of ischemic heart disease and several cancers. The pathophysiology of these diseases involves free radical mechanisms. Diet may either enhance or diminish oxidative stress in the body.


OBJECTIVE
We studied the effects of high and low intakes of vegetables, berries, and apples on markers of lipid peroxidation and lipoprotein metabolism in subjects consuming diets high in linoleic or oleic acid.


METHODS
For 6 wk, healthy men and women (n = 77; aged 19-52 y) consumed 1 of 4 controlled isoenergetic diets rich in either linoleic acid (11% of energy) or oleic acid (12% of energy) and containing either 815 or 170 g vegetables, berries, and apples/10 MJ. Nineteen healthy volunteers served as control subjects. Several markers of dietary compliance (plasma fatty acids, vitamin C, carotenoids, and quercetin), lipid peroxidation [ex vivo LDL oxidation, plasma and LDL thiobarbituric acid-reactive substances, paraoxonase (EC 3.1.8.1), and urinary 8-iso-prostaglandin F(2)(alpha)], and lipoprotein metabolism (plasma lipids, apolipoproteins, and lipid transfer protein activities) were measured from samples collected before and at the end of the experimental period.


RESULTS
Plasma fatty acid composition and antioxidant concentrations showed that compliance with the diets was good. However, there were no significant differences between the diets in the markers of lipid peroxidation and lipoprotein metabolism.


CONCLUSIONS
In healthy volunteers with adequate vitamin intakes, 6-wk diets differing markedly in the amounts of linoleic and oleic acid and vegetables, berries, and apples did not differ in their effects on lipid peroxidation or lipoprotein metabolism.
Freese
Riitta
R
University of Helsinki, Department of Applied Chemistry and Microbiology, Division of Nutrition, Finland. riitta.freese@helsinki.fi
Alfthan
Georg
G
Jauhiainen
Matti
M
Basu
Samar
S
Erlund
Iris
I
Salminen
Irma
I
Aro
Antti
A
Mutanen
Marja
M
D000328:Adult; D015415:Biomarkers; D004032:Diet; D005260:Female; D005638:Fruit; D006801:Humans; D019787:Linoleic Acid / Q000008:administration & dosage*; D015227:Lipid Peroxidation; D008074:Lipoproteins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D019301:Oleic Acid / Q000008:administration & dosage*; D012016:Reference Values; D014675:Vegetables
D015415:Biomarkers; D008074:Lipoproteins; D019301:Oleic Acid; D019787:Linoleic Acid