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Advisor(s)
Abstract(s)
Tem sido frequentemente referido em estudos
epidemiológicos e ensaios clínicos que o tipo
de dieta consumida e, em particular, a sua
composição lipídica, além de se repercutir no
metabolismo corporal pode interferir no
desenvolvimento da aterosclerose e
subsequentes complicações cardiovasculares.
A dieta do “tipo ocidental” (rica em lípidos
saturados, açúcares simples e sal, e pobre em
peixe, vegetais e fibra) tem sido associada a
uma maior tendência pró-inflamatória, próoxidante e pró-trombótica e, por consequência, a um maior risco cardiovascular. Em contraste, a dieta do “tipo Mediterrânico” (à base de mais
peixe e pouca carne, fibras, fruta, vegetais e azeite e vinho) parece justificar a menor
incidência de doença cardiovascular
(e de cancro) nas populações consumidoras.
Em posição intermédia parecem encontrar-se
os grupos populacionais que consomem dietas
preferencialmente ricas em ácidos
gordos poli-insaturados.
A actual carência de ensaios populacionais e
clínicos randomizados e sob controlo rigoroso
que relacionem as intervenções dietéticas com
eventos cardiovasculares, primários ou
secundários, poderá justificar algumas das
divergências por vezes referidas. Também
explicará a escassez de resultados
esclarecedores sobre os mecanismos
eventualmente dependentes da dieta utilizada
no desenvolvimento da aterosclerose.
Na generalidade, admite-se que as
características morfológicas e funcionais do
endotélio vascular possam ser afectados pelos
constituintes absorvidos da dieta. A exposição sustentada a determinados componentes adversos poderá constituir um risco de disfunção endotelial, evidenciado pela diminuição de mediadores anti-trombóticos, anti-oxidantes, anti-inflamatórios e vasodilatadores periféricos, que constitui também um primeiro passo para a instalação da aterosclerose.
Entre os principais mecanismos propostos
destaca-se o efeito pró-inflamatório e próoxidante do excesso de colesterol na função endotelial, em contraste com o efeito
aparentemente benéfico dos ácidos gordos
mono-insaturados e os resultados mais
contraditórios induzidos pelos ácidos gordos
poli-insaturados.
Epidemiologic studies and clinical trials have shown that diet and, in particular, the consumption of fats, influence the body's metabolism and can affect the development of atherosclerosis and resulting cardiovascular repercussions. A Western-type diet (high in saturated fats, simple sugars and salt, and low in fish, vegetables and fiber) has been associated with proinflammatory, pro-oxidative and prothrombotic tendencies and consequently higher cardiovascular risk. By contrast, a Mediterranean-type diet (with less meat and more fish, fiber, fruit, vegetables, olive oil and wine) appears to explain the lower tendency for cardiovascular disease (and cancer) in those who consume it. Between these two are population groups who prefer diets rich in polyunsaturated fatty acids. The lack of randomized and rigorously controlled population and clinical trials relating types of diet to primary or secondary cardiovascular events may explain some of the disagreements surrounding this subject. It would also explain the lack of results that shed light on diet-dependent mechanisms that may affect the development of atherosclerosis. In general, it is accepted that the morphologic and functional characteristics of vascular endothelium are influenced by the components absorbed from the diet. Prolonged exposure to certain harmful components in the diet may increase the risk of endothelial dysfunction, as shown by a decrease in antithrombotic, antioxidative, anti-inflammatory and peripheral vasodilatory modulators, which represents the first step towards the onset of atherosclerosis. Among the main mechanisms involved in endothelial dysfunction are the proinflammatory and prooxidative effects of excess cholesterol, in contrast with the apparent benefit of monounsaturated fatty acids and the less consistent results obtained with polyunsaturated fatty acids.
Epidemiologic studies and clinical trials have shown that diet and, in particular, the consumption of fats, influence the body's metabolism and can affect the development of atherosclerosis and resulting cardiovascular repercussions. A Western-type diet (high in saturated fats, simple sugars and salt, and low in fish, vegetables and fiber) has been associated with proinflammatory, pro-oxidative and prothrombotic tendencies and consequently higher cardiovascular risk. By contrast, a Mediterranean-type diet (with less meat and more fish, fiber, fruit, vegetables, olive oil and wine) appears to explain the lower tendency for cardiovascular disease (and cancer) in those who consume it. Between these two are population groups who prefer diets rich in polyunsaturated fatty acids. The lack of randomized and rigorously controlled population and clinical trials relating types of diet to primary or secondary cardiovascular events may explain some of the disagreements surrounding this subject. It would also explain the lack of results that shed light on diet-dependent mechanisms that may affect the development of atherosclerosis. In general, it is accepted that the morphologic and functional characteristics of vascular endothelium are influenced by the components absorbed from the diet. Prolonged exposure to certain harmful components in the diet may increase the risk of endothelial dysfunction, as shown by a decrease in antithrombotic, antioxidative, anti-inflammatory and peripheral vasodilatory modulators, which represents the first step towards the onset of atherosclerosis. Among the main mechanisms involved in endothelial dysfunction are the proinflammatory and prooxidative effects of excess cholesterol, in contrast with the apparent benefit of monounsaturated fatty acids and the less consistent results obtained with polyunsaturated fatty acids.
Description
Copyright © 2007 Sociedade Portuguesa de Cardiologia. All rights reserved.
Keywords
Atherosclerosis Diet Endothelium Fatty acids
Pedagogical Context
Citation
Rev Port Cardiol 2007; 26 (3):277-294
Publisher
Elsevier España