Use and misuse of dietary fatty acids for the prevention and treatment of coronary heart disease

Abstract

-In the recent years, the health effects of fish (and n-3 fatty acids) have attracted considerable scientific interest. The present consensus is that the cardioprotection of very long chain n-3 fatty acids (also called EPA and DHA) at the low dosage used in recent secondary prevention trials primarily results from an effect on the ischemic myocardium and probably not from an effect on blood lipids and hemostasis. In other words, at these low dosages, there is apparently no major effect of these fatty acids on the progression of the vascular atherosclerotic lesions. In contrast, dietary alpha-linolenic acid (ALA), the parent compound of the very long chain n-3 fatty acids occurring in some vegetable oils, may be protective through mechanisms other than the myocardial (antiarrhythmic) ones. In addition to its own direct preventive effect on cardiac arrhythmias, dietary ALA actually inhibits the elongation and desaturation of linoleic acid (18:2 n-6) into arachidonic acid. Because arachidonic acid (20:4 n-6) plays an important role in inflammation (as the precursor of the proinflammatory eicosanoids and leukotrienes), modifying its amount in blood and cell membranes influences the prevalence and severity of eicosanoid-related disorders, including atherosclerotic complications. The present knowledge of n-3 fatty acids justifies that physicians, in particular cardiologists in the context of secondary prevention of coronary heart disease, manage their patients, the young and the old, to increase their consumption of these fatty acids. They can only advise them to adequately adapt their diet (for instance in primary prevention), but in most cases, the systematic prescription of capsules containing oils enriched in ALA and EPA + DHA will be, ethically and scientifically, an obligation. coronary heart disease / dietary fatty acids / fish / inflammation / sudden cardiac death / atherosclerosis / nutritionSince Scandinavian investigators suggested that the low mortality rate from coronary heart disease (CHD) among Greenland Eskimos as compared to Europeans might be due to their diet including large quantities of seafood [1], the health effects of fish (and n-3 fatty acids) have attracted considerable scientific interest. Meanwhile, most epidemiological studies have demonstrated a protective effect linked to the consumption of even small amounts of fish. The controversy surrounding the association between fish consumption and CHD has, however, been revived by the recent publication of negative results in two large cohort studies in the USA [2,3] and by the inconsistent findings of another two studies [4,5]. This apparent inconsistency in results could be due to the following: (1) differences in the methods of dietary assessment

Erythrocyte membranetrans-fatty acid index is positively associated with a 10-year CHD risk probability

“…CHD incidence could be influenced directly or indirectly by TFA through TAG accumulation, vasodilation, inflammation, PG translation and/or platelet aggregation ( 8 , 39 ) . Trans -fatty acids elicit an unfavourable effect on the lipoprotein profile by stimulating cholesteryl ester transfer protein activity ( r 0·58, P < 0·005), increasing the LDL level and decreasing the HDL level ( r − 0·57, P < 0·01).…”

Butters rich either in trans-10-C18:1 or in trans-11-C18:1 plus cis-9, trans-11 CLA differentially affect plasma lipids and aortic fatty streak in experimental atherosclerosis in rabbits

“…Moreover, intake of trans FArich butters lowered the plasma content of total n-3 FA and particularly C 18:3 n-3, despite the fact that all diets provided the same amounts of C 18:3 n-3 and C 18:2 n-6. The decrease in plasma content of C 18:3 n-3 could be detrimental, since it is the precursor of the n-3 FA family, for which the cardio-protective properties have been well established (De Lorgeril and Salen, 2004).…”

Conceitos atuais e perspectivas na prevenção da degeneração macular relacionada à idade

“…As propriedades cardioprotetoras dos ácidos graxos ômega-3 já são estudadas há alguns anos (110)(111)(112)(113)(114) . Entre os principais mecanismos estudados, está o efeito protetor contra arritmias (115)(116) , efeitos no perfil lipídico (117)(118) , principalmente redução dos níveis séricos de triglicerídeos (119)(120)(121) , efeito antioxidante (122)(123)(124)(125) e antiinflamatório (126)(127) .…”