Tomato consumption and health: its association with cardiovascular diseases and effects on traditional and novel cardiovascular risk factors

Cheng, Ho Ming (2018) Tomato consumption and health: its association with cardiovascular diseases and effects on traditional and novel cardiovascular risk factors. Doctoral thesis, Northumbria University.

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Abstract

Cardiovascular diseases (CVD) are the leading causes of deaths representing 31% of global deaths. A healthy dietary eating pattern characterised by a greater intake of fruit and vegetables is associated with a reduction in the risk of CVD. Whether specific fruit and vegetables differ in the health benefits need further research.

The systematic reviews and meta-analysis of previous relevant literature that were undertaken for this PhD programme showed positive associations between higher tomato and/or lycopene intake or status were associated with significant reductions of 26% in stroke (p=0.001), 14% in CVD (p=0.003); while high serum lycopene concentration was associated with significant reduction of 37% in mortality (p>0.001). In addition, previous dietary intervention studies have shown that supplementing tomatoes were associated with significant reductions of LDL-cholesterol by 0.22 mmol/L (p=0.006) and IL-6 by 0.25pg/mL (p=0.03) and improvement of FMD by 2.53% (p=0.01); while supplementing lycopene was associated with significant reduction in SBP by 5.66 mmHg (p=0.002), but its effects on other markers of endothelial function has not been fully investigated.

These literature reviews informed further research in this PhD programme. Previous RCT investigating the effects of tomato consumption have focused only on red tomatoes, red-tomato products, or lycopene supplementations, and the effects of different tomato varieties on markers of cardiovascular risk had not been previously evaluated, and was therefore identified as a gap in the literature. With new varieties of tomato available to the public, it is important to evaluate whether other varieties exert the same effect, and this was the aim of further work on this research programme.

A 12-week, cross-over, randomised controlled dietary interventional study was undertaken to compare the effects of supplementing 300 g of two tomato varieties, red cherry tomato (Piccolo) and orange cherry tomato (Oranjstar) on cardiovascular health. Overall, this study provided evidence on the benefits of consumption Piccolo, for four weeks, has a significant impact on reducing both nighttime ambulatory SBP by 4.52 mmHg (p=0.039) and DBP by 3.82 mmHg (p=0.016), improving FMD by 3.43% (p=0.026), while Oranjstar has significant impact on reducing adhesion molecules sICAM-1, sVCAM-1 and E-selectin by 59.14 ng/mL (p<0.001), 67.35 ng/mL (p=0.003) and 6.65 ng/mL(p<0.016) respectively. Therefore, lowering the risk of cardiovascular disease in healthy, particularly in older, adult males.

The findings reported in the present thesis could be valuable to different health professionals to develop more effective interventions and could also help the public to make better informed food choices relating to cardiovascular health.

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