Eur J Nutr 42: 201– 206 (2003) DOI 10.1007/s00394-003-0415-5 ■ Summary Background It has been suggested that regular con- sumption of tomato products im- proves antioxidant defenses due to their endogenous antioxidant com- pounds, notably lycopene. Aim of the study We evaluated the effects Received: 4 December 2002 Accepted: 17 February 2003 Dr. F. Visioli () · S. Grande · C. Galli Department of Pharmacological Science University of Milan Via Balzaretti 9 20133 Milano, Italy Fax: +39-02/700-426-106 E-Mail: francesco.visioli@unimi.it P. Riso · M. Porrini Department of Food Science and Technology and Microbiology Division of Human Nutrition University of Milan Via Celoria 2 20133 Milano, Italy of tomato consumption on param- eters of lipid oxidation in healthy human volunteers. Methods Twelve females (enrolled at T-7), after a one-week of carotenoid-poor diet (T0), were instructed to supple- ment the same diet with different tomato products (raw, sauce, and paste), thereby providing approxi- mately eight mg lycopene/day for three weeks (T21). Blood samples were periodically collected in order to evaluate plasma carotenoid con- centrations, plasma antioxidant ca- pacity, and susceptibility of LDL to metal ion-induced oxidation. Fur- thermore, 8-iso-PGF 2α , a marker of in vivo oxidative stress, was ana- lyzed in the 24-hour urine. Results Carotenoid concentrations de- creased significantly during the carotenoid-poor diet (P < 0.05), while lycopene concentrations in- creased significantly after tomato consumption (P < 0.001). The an- tioxidant capacity of plasma did not vary during the study. Con- versely, LDL oxidizability de- creased after tomato consumption, as demonstrated by a shortening of the lag phase (P < 0.001). This pa- rameter was significantly corre- lated with lycopene concentration (r = 0.36, P < 0.05). The excretion of 8-iso-PGF 2α in urine was also sig- nificantly lower (–53 %, P < 0.05 compared with T0) after tomato supplementation. Conclusions These results further support a role for tomato products in the preven- tion of lipid peroxidation, a risk factor of atherosclerosis and car- diovascular disease. ■ Key words lipid peroxidation – LDL – isoprostane – tomato – lycopene – humans ORIGINAL CONTRIBUTION Francesco Visioli Patrizia Riso Simona Grande Claudio Galli Marisa Porrini Protective activity of tomato products on in vivo markers of lipid oxidation Introduction Lipid peroxidation, namely low-density lipoprotein (LDL) oxidation, is thought to contribute to the onset and development of degenerative diseases, such as car- diovascular disease and atherosclerosis [1–3], and may be indirectly involved in the promotion of DNA damage and consequently cancer [4, 5]. The study of dietary fac- tors that may limit lipid damage triggered by radicals is crucial for optimization of diets aimed at reducing the risk of degenerative disease through potentiation of the endogenous antioxidant defense system. Although it is usually difficult to attribute outright health effects to individual dietary components, some, albeit not all [6], epidemiological studies have shown in- verse correlations between high lycopene consumption, notably through tomatoes, and the incidence of diseases such as coronary heart disease (CHD) and cancer [7–11]. These results, together with an understanding of the contribution of excessive free radical generation in the onset of these diseases [2], led to the hypothesis that a high proportion of dietary antioxidants – including tomato-derived carotenoids and lycopene – might play a preventive role [11, 12]. Lycopene is an open-chain, unsaturated, red-colored EJN 415