STUDY FINDS EATING FRUIT AND VEG DOESN'T REDUCE HEART RISK

From the Division of Nutrition, University of Helsinki (RF and MM); the Biomarker Laboratory (GA IE, IS, and AA) and the Department of Molecular Medicine (MJ), National Public Health Institute, Helsinki; and the Section of Geriatrics, Faculty of Medicine, Uppsala University, Uppsala, Sweden (SB).

ABSTRACT

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.

Design: 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.

COMMENT: This was the first of several studies which looked into the claim that "5 portions of fruit and veg a day" reduced the risk of coronary heart disease and cancer. None of these studies found any evidence to support or substantiate those claims. Despite this, people five years later are still dictated to and told that they must eat at least five portions of fruit and veg. There are even moves afoot to increase the amounts in the vain, and again unsupported, hope that if people eat enough fruit and veg, there will eventually be a benefit. They are living in cloud cuckoo land.

Last updated 3 March 2007