Abstract Body (Do not enter title and authors here): Introduction: It has been described that both skin and coronary microvascular dysfunction occur in coronary heart disease patients, being a critical pathogenesis of cardiovascular diseases, mainly driven by a reduced endothelium-derived relaxing factor nitric oxide availability, the main homeostatic antioxidant in microcirculation. Various dietary factors could modulate endothelial function. Our goal was to evaluate the relationship between nutrition and long-term microvascular endothelial function in patients in secondary cardiovascular prevention. To do this, we evaluated the consumption of two healthy diets (Mediterranean Diet and Low-fat diet) and the total antioxidant content of the diet.

Methods: With an analytical, longitudinal, experimental, and retrospective design, this work included all patients from the Cordioprev study who had completed endothelial function measures and dietary evaluations at the start of the study and after six years of intervention (n=520). Endothelial function (basal flow and area of reactive hyperemia) was measured using laser-Doppler flowmetry in the second phalanx of the third finger of the dominant hand. Food intake was evaluated using a food frequency questionnaire and the antioxidant quality of the diet using the dietary antioxidant index.

Results: In the entire population, we observed a significant direct correlation between the evolution of the dietary antioxidant index and basal flow after 6 years of dietary intervention (p=0.024). When we studied the effect of the two diets investigated, in the Mediterranean diet group, an increase in the average dietary antioxidant index score was observed at the end of the study, and a direct relationship was also found between the dietary antioxidant index and endothelial function markers (basal flow (p=0.037); area of reactive hyperemia (p=0.015)). These findings were not observed after the low-fat diet.

Conclusions: Our study indicates that, after six years of dietary intervention, changes in the total antioxidant content of the diet are directly correlated with changes in microvascular endothelial function in patients with coronary disease. These findings are especially evident with the Mediterranean Diet.