CORRESPONDENCE: LETTER TO THE EDITOR
Virgin Olive Oil and Vegetables Improve Endothelial Health
Dario Giugliano, MD, PhD* and
Katherine Esposito, MD, PhD
* Division of Metabolic Diseases, University of Naples SUN, Piazza L. Miraglia, 80138 Naples, Italy (Email: dario.giugliano{at}unina2.it).
We read with interest the study by Ruano et al. (1) showing that a meal containing high-phenolic virgin olive oil improves ischemic reactive hyperemia during the postprandial state. As virgin olive oil may represent the major fat constituent of the Mediterranean diet, at least in countries where olive oil consumption is high, these findings seem to add circumstantial evidence to the cardiovascular benefits already known to occur in subjects adhering to a Mediterranean-style diet (2). However, it seems unlikely that people in everyday life can consume 60 g of white bread added with 40 ml of virgin olive oil as a meal, even in countries characterized by moderate-to-high intake of daily olive oil. In recent large-scale epidemiological studies, the median dietary intake of olive oil in a typical Mediterranean country, such as Greece, was 45 g/day (2).
Endothelial activation and impairment of endothelium-dependent vasodilation have been observed with fat-rich meals, mostly rich in saturated fats, even in subjects without clinical and laboratory evidence of risk factors for coronary heart disease. For instance, ingestion of the high-fat meal (760 kcal, 59% energy from fat, 50 g of saturated fat) consisting of two sausages (80 g), six bread slices (90 g), an egg (40 g), butter (15 g), and olive oil (5 g) has been shown to increase the circulating levels of soluble forms of cellular adhesion molecules, such as vascular adhesion molecule-1 and intercellular adhesion molecule-1 (3), considered to be an index of endothelial activation. A high-saturated-fat meal is also associated with increased circulating levels of endothelial microparticles, indicating structural endothelial damage (4).
Finally, the addition of antioxidant supplements (3) or vegetables to the meal (5) has been shown to reverse the increase in circulating adhesion molecules, proinflammatory cytokines, such as interleukin-6 and tumor necrosis factor-alpha, and endothelial dysfunction induced by a single high-fat (saturated) meal consumption. In a more general sense, a high-saturated-fat meal seems to switch the endothelium toward a more athrogenetic profile; both monounsaturated fats, such as olive oil rich in phenolic acid content, and vegetables help prevent endothelial activation and dysfunction in the postprandial state.
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1. Ruano J, Lopez-Miranda J, Fuentes F, et al. Phenolic content of virgin olive oil improves ischemic reactive hyperemia in hypercholesterolemic patients J Am Coll Cardiol 2005;46:1864-1868.[Abstract/Free Full Text]2. Trichopoulou A, Costacou T, Bamia C, Trichopoulos D. Adherence to a Mediterranean diet and survival in a Greek population N Engl J Med 2003;348:2599-2608.[Abstract/Free Full Text] 3. Nappo F, Esposito K, Cioffi M, et al. Postprandial endothelial activation in healthy subjects and in type 2 diabetic patientsrole of fat and carbohydrate meals. J Am Coll Cardiol 2002;39:1145-1150.[Abstract/Free Full Text] 4. Ferreira AC, Peter AA, Mendez AJ, et al. Postprandial hypertriglyceridemia increases circulating levels of endothelial cell microparticles Circulation 2004;110:3599-3603.[Abstract/Free Full Text] 5. Esposito K, Nappo F, Giugliano F, et al. Effect of dietary antioxidants on postprandial endothelial dysfunction induced by a high-fat meal in healthy subjects Am J Clin Nutr 2003;77:139-143.[Abstract/Free Full Text]
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