In July 2006, a research database was constructed to manage the most up-to-date research describing the diet-disease relationship for tomatoes, tomato products and lycopene. This database was updated in 2007, 2009 and now again in 2011 (cut off Oct 2011 for published original research).
One hundred and sixteen (116) original research articles were identified investigating the association between tomato/tomato-based foods and or lycopene and cardiovascular disease risk. Main findings are based on results using lipids, oxidative stress, inflammation, endothelial function, platelet function, intima medial thickness, acute coronary events and blood pressure as primary or secondary endpoints. The association between tomato/tomato-based foods remains relatively strong for a protective relationship between consumption of these foods and lower risk of cardiovascular disease, as measured by oxidative stress; and in one study, as measured by incidence of first myocardial infarction. Additionally, beneficial findings related to HDL have surfaced with 3 studies showing increases in HDL after an intervention with tomato/tomato-based foods. Data remain inconclusive on the relationship of tomato/tomato-based foods and modifying inflammation, endothelial function, and blood pressure; however, recent publications are exploring these endpoints. Two newer studies [one in individuals with diabetes and another in overweight individuals, particularly those with pre-hypertension (Burton-Freeman et al. in press] have shown decreases in blood pressure with tomato intake, suggesting that tomato intake may be advantageous in keeping blood pressure from increasing to levels requiring medication in at risk populations. Follow up studies investigating the blood pressure lowering effects and benefits on HDL metabolism are warranted.
One PC investigation suggests increased vascular risk based on elevated pro-thrombotic factors in higher consumers of tomato/tomato-based foods. These data are in contrast to earlier reports suggesting anti-thrombotic effects of fresh tomato seed (membrane) extracts. Follow up research is required to reconcile these differences.
Plasma/serum lycopene concentrations and cardiovascular disease risk are mixed with both protective and neutral relationships reported in nearly equal ratio. Large prospective cohort investigations support a protective relationship between plasma/serum lycopene concentrations and future coronary events and death due to cardiovascular disease; although this relationship may not extend to stroke. Mixed results are reported for lycopene supplementation on all endpoints, including blood pressure. However, recent work supports testing the hypothesis that combination therapy including lycopene supplementation will have beneficial effects on blood pressure regulation. Additional research is required to understand the therapeutic and preventive opportunities with lycopene supplementation using combination strategies.