Tomato Consumption and High Density Lipoprotein-cholesterol

Overview

* This is a randomized, open-label, single blind, clinical trial * The study evaluated the effect of tomato consumption in serum HDL-cholesterol levels. * The hypothesis was that two daily tomatoes during one month will increase the HDL-c levels. * Since a placebo of tomatoes cannot be done, the control group will receive same proportion of cucumber because 1) it was not possible to have a tomato placebo; 2) cucumber does not have any lycopene; 3) both can be prepared similarly; and 4) the required quantity can be measured in the same way. * The intervention was during 1 month and was assigned by randomization. * Personnel who did the clinical and biochemical evaluation were blinded for the intervention. * Lipid profile was measured before and after the intervention. * Confounding factors such as daily physical activity, diet, consumption of fish or alcoholic beverages, smoking status were considered during statistical analyses.

Cardiovascular disease (CVD) is a main cause of death worldwide (1) and there are well recognized risk factors associated with its development. Low high density lipoprotein-cholesterol (HDL-c) rank among the most common lipid abnormalities associated with CVD (2). Low HDL-c is currently defined as an HDL-c value below 40 mg/dL for men and below 50 mg/dL for women (3). Factors related with low HDL-c are cigarette smoking (4), high triglycerides (5), sedentary lifestyle (6), and insulin resistance (7). Non-pharmacologic strategies to increase HDL-c concentration are increasing alcohol (8) and fish consumption (9), weight reduction (3), increment in physical activity (10), and smoking cessation (8). Some of these strategies are not applicable or hard to implement in individuals affected with low HDL-c. Moreover, in low-income countries, these interventions could be costly for the general population. Vegetables consumption could be a more affordable and accessible option to treat low HDL-c. Epidemiologic evidence indicates that high consumption of vegetables reduces the risk of cardiovascular disease (11) and particular attention has received tomato-based products. Growing evidence from several epidemiological studies has indicated that lycopene, the major carotenoid in tomato (12), might be more important than other carotenoids in preventing atherosclerosis and CVD (13, 14). The consumption of more than 7 servings per week of tomato-based products has been associated with a 30% reduction in the relative risk of CVD (15). Such potential benefits to vascular health from a tomato-rich diet could be related to low arterial intimal wall thickness (13, 16), reduction of LDL cholesterol levels (17), and inverse correlation with markers of inflammation and vascular endothelial dysfunction (18). However, HDL-c levels could also be positively influenced by tomato consumption. In a pilot study we found that tomato juice consumption did not increase HDL-c after one month (unpublished data), this finding also was recently reported by another group (19). In contrast, other study showed that daily consumption of 300g of uncooked tomatoes, during one month significantly increased HDL-c levels by 15.2% (20). However, this study was not controlled, not blinded, and neither randomized. Roma tomatoes consumption could be an accessible intervention to improve HDL-c levels; however, a longitudinal clinical trial is necessary to evaluate this association. Therefore, we performed a randomized, open-label, single blind, clinical trial to specifically evaluate if consumption of two uncooked tomatoes per day (14 servings/week) during one month could produce a favorable effect on HDL-c.