Effect of supplementation with tomato juice, vitamin E, and vitamin C on LDL oxidation and products of inflammatory activity in type 2 diabetes.
What this study found
Overall, tomato juice and vitamin E improved LDL resistance to oxidation, while vitamin E also reduced C-reactive protein; vitamin C showed a smaller and less consistent effect. Tomato juice increased LDL oxidation lag time to 101 ± 27 min and raised plasma lycopene to 1.08 ± 0.39 µmol/l. Vitamin E increased lag time to 114 ± 26 min, increased plasma alpha-tocopherol to 56.7 ± 23.7 µmol/l, and reduced C-reactive protein. Vitamin C increased lag time to 67 ± 18 min, but C-reactive protein remained 4.1 (1.2-14.6) mg/l and no significant changes were reported for VCAM-1 or ICAM-1. The authors…
- Study & population
- Adults with well-controlled type 2 diabetes under 75 years of age were studied.
- Intervention
- Three oral supplementation regimens were evaluated for 4 weeks: vitamin E, 800 IU/day D-alpha-tocopherol from a natural source; vitamin C, 500 mg/day; and tomato juice, 250 ml twice daily (500 ml/day).
- Key limitation
- The active arms were small, with only 12 to 15 participants per supplement, and the intervention lasted just 4 weeks.
View source
Open PDFOriginal abstract
OBJECTIVE To compare the effects of short-term dietary supplementation with tomato juice, vitamin E, and vitamin C on susceptibility of LDL to oxidation and circulating levels of C-reactive protein (C-RP) and cell adhesion molecules in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS There were 57 patients with well-controlled type 2 diabetes aged <75 years treated with placebo for 4 weeks and then randomized to receive tomato juice (500 ml/day), vitamin E (800 U/day), vitamin C (500 mg/day), or continued placebo treatment for 4 weeks. Susceptibility of LDL to oxidation (lag time) and plasma concentrations of lycopene, vitamin E, vitamin C, C-RP, vascular cell adhesion molecule 1, and intercellular adhesion molecule 1 were measured at the beginning of the study, after the placebo phase, and at the end of the study. RESULTS Plasma lycopene levels increased nearly 3-fold (P = 0.001), and the lag time in isolated LDL oxidation by copper ions increased by 42% (P = 0.001) in patients during supplementation with tomato juice. The magnitude of this increase in lag time was comparable with the corresponding increase during supplementation with vitamin E (54%). Plasma C-RP levels decreased significantly (-49%, P = 0.004) in patients who received vitamin E. Circulating levels of cell adhesion molecules and plasma glucose did not change significantly during the study. CONCLUSIONS This study indicates that consumption of commercial tomato juice increases plasma lycopene levels and the intrinsic resistance of LDL to oxidation almost as effectively as supplementation with a high dose of vitamin E, which also decreases plasma levels of C-RP, a risk factor for myocardial infarction, in patients with diabetes. These findings may be relevant to strategies aimed at reducing risk of myocardial infarction in patients with diabetes.