a1 Department of Internal Medicine, University of Oulu, P.O. Box 5000, 90014 Oulu, Finland
a2 Biocenter Oulu, P.O. Box 5000, 90014 University of Oulu, Oulu, Finland
a3 National Public Health Institute (KTL), Mannerheimintie 166, 00300 Helsinki, Finland
a4 Department of Farmacology and Toxicology, University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland
High dietary intakes of tomato products are often associated with a reduced risk of CVD, but the atheroprotective mechanisms have not been established. This study was conducted to investigate the effects of increased dietary intake of tomato products on plasma lipids and LDL oxidation. The diet intervention included a baseline period, a 3-week low tomato diet (no tomato products allowed) and a 3-week high tomato diet (400 ml tomato juice and 30 mg tomato ketchup daily). Twenty-one healthy study subjects participated in the study. Total cholesterol concentration was reduced by 5·9 (sd 10) % (P = 0·002) and LDL cholesterol concentration by 12·9 (sd 17·0) % (P = 0·0002) with the high tomato diet compared to the low tomato diet. The changes in total and LDL cholesterol concentrations correlated significantly with the changes in serum lycopene (r 0·56, P = 0·009; r 0·60, P = 0·004, total and LDL, respectively), β-carotene (r 0·58, P = 0·005; r 0·70, P < 0·001) and γ-carotene concentrations (r 0·64, P = 0·002; r 0·64, P = 0·002). The level of circulating LDL to resist formation of oxidized phospholipids increased 13 % (P = 0·02) in response to the high tomato diet. In conclusion, a high dietary intake of tomato products had atheroprotective effects, it significantly reduced LDL cholesterol levels, and increased LDL resistance to oxidation in healthy normocholesterolaemic adults. These atheroprotective features associated with changes in serum lycopene, β-carotene and γ-carotene levels.
(Received January 24 2007)
(Revised April 26 2007)
(Accepted April 30 2007)