0301 : Effects of low and high polyphenols content lettuces consumption on high fat diet induced metabolic syndrome and endothelial dysfunction

Abstract

Consumption of vegetables has been recommended to reduce the risk of cardiovascular disease. The protection against disease is partly due to bioactive molecules including polyphenols. In order to evaluate the effects of such polyphenols, we supplemented High Fat diet rats with low and high polyphenolic content lettuces. 32 Wistar rats were divided in 4 groups, a control group (Ctrl), a high fat and sucrose diet group (HFS, 60% fat+10%sucrose) and 2 groups that after 6 weeks of HFS diet were supplemented 8 weeks with both HFS diet and either a low or high polyphenol content lettuces (HFS-LP; Blond Oak Leaf, 30g/day vs. HFS-HP; Red Oak Leaf, 30g/day). After 14 weeks of HF diet including 8 weeks of supplementation, we performed a glucose tolerance test and an evaluation of arterial blood pressure (BP) by tail cuff method. Then, aortic endothelial function and eNOS dependent vasodilatation were evaluated ex vivo on isolated rings. Firstly, we observed a higher body weight in HFS group (502±21g) compared to Ctrl group (417±14g) without any effect of both supplementations. Regarding glycemic control, HFS group presented increased fasting blood glucose (1,37g/l vs. 1,20g/l) as well as an impairment of glucose tolerance. Interestingly, both groups with lettuces intake displayed healthy fasting blood glucose values (1.14g/l and 1.15g/l) and an improvement of glucose tolerance. Moreover, both lettuces treatments managed to normalize the increase in mean BP observed in HFS group (HFS; 131mmHg; HFS-LP 120 mmHg; HFS-HP, 117mmHg). However, no effect of lettuce consumption was observed on endothelial dysfunction and impaired eNOS dependent vasodilatation observed in HFS rats. In conclusion, we observed in this study a major effect of lettuce intake on glycemic control as well as arterial BP. However, no effect regarding the difference in polyphenols content has been reported here underlying that the effects were independent of the specific polyphenols contained in the HP lettuce.