Volume 33, Issue 10 p. 981-984
Article

Tomato lycopene and low density lipoprotein oxidation: A human dietary intervention study

Sanjiv Agarwal

Sanjiv Agarwal

Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, M5S 3E2 Canada

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A. Venketeshwer Rao

Corresponding Author

A. Venketeshwer Rao

Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, M5S 3E2 Canada

To whom correspondence should be addressed at Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 3E2, Canada. E-mail: [email protected]Search for more papers by this author
First published: 01 October 1998
Citations: 311

Abstract

Increase in low density lipoprotein (LDL) oxidation is hypothesized to be causally associated with increasing risk of atherosclerosis and coronary heart disease. In recent epidemiological studies, tissue and serum levels of lycopene, a carotenoid available from tomatoes, have been found to be inversely related to risk of coronary heart disease. A study was undertaken to investigate the effect of dietary supplementation of lycopene on LDL oxidation in 19 healthy human subjects. Dietary lycopene was provided using tomato juice, spaghetti sauce, and tomato oleoresin for a period of 1 wk each. Blood samples were collected at the end of each treatment. Serum lycopene was extracted and measured by high-performance liquid chromatography using an absorbance detector. Serum LDL was isolated by precipitation with buffered heparin, and thiobarbituric acid-reactive substances (TBARS) and conjugated dienes (CD) were measured to estimate LDL oxidation. Both methods, to measure LDL oxidation LDL-TBARS and LDL-CD, were in good agreement with each other. Dietary supplementation of lycopene significantly increased serum lycopene levels by at least twofold. Although there was no change in serum cholesterol levels (total, LDL, or high-density lipoprotein), serum lipid peroxidation and LDL oxidation were significantly decreased. These results may have relevance for decreasing the risk for coronary heart disease.