摘要:

Not more than 10 years ago, most of us knew very little about n‐3 polyunsaturated fatty acids. The message to both the patient and the physician with regard to fatty acids and fats in the diet was based largely on over‐simplified information. For example, saturated fats were said to be ‘bad’. A high consumption of saturated fats increased both blood cholesterol and the risk of coronary heart disease (CHD). In contrast, the polyunsaturated fatty acids in the diet were thought to be basically ‘good’. They reduced serum cholesterol and may have delayed the development of atherosclerosis.The lesson learnt from the Greenland Eskimos did not really change this concept, but has taught us more about some of the mechanisms involved [1, 2]. Today a common interest in regard to the potential benefit of n‐3 fatty acids is shared by almost everybody interested in the treatment and prevention of CHD. The diverse effects of twenty‐carbon fatty acids of the n‐6 and n‐3 families on platelet and vessel wall function, prostaglandin synthesis and lipoprotein metabolism, make them of special interest in relation to thrombosis and

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01428.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Dietary n‐3 fatty acids modify the fatty acid composition of phospholipids of different cells and tissues from rats in diverse ways. Neutrophil and platelet phospholipids contain elevated amounts of 20: 5n‐3, but only relatively small changes occur in the levels of 22‐carbon n‐3 fatty acids. Conversely, dietary n‐3 acids result primarily in an increase in 22‐carbon n‐3 acids in heart, liver and kidney phospholipids. Platelets metabolize exogenous n‐6 and n‐3 fatty acids into a variety of different autocoids. However, it appears that only arachidonate and 20:5n‐3 are released from phospholipids upon agonist‐induced stimulation of phospholipases. Neutrophils metabolize arachidonate and 20: 5n‐3 in similar ways, both relative to phospholipid biosynthesis and the subsequent release of these acids for metab

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01429.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.It may be hypothesized that many diseases are associated with an overproduction of eicosanoids from the n‐6 acid, arachidonic acid (20:4n‐6), and the formation and function of these n‐6 eicosanoids can be antagonized by dietary n‐3 fats. This hypothesis provides a basis for evaluating the benefits and risks of including various amounts of n‐3 and n‐6 fats in the diet. Understanding the impact of dietary polyunsaturated fats leads inevitably to a reappraisal of what is ‘normal’ in terms of what is typical and what is desirable for the fatty acid composition of tissue lipids, the magnitude of eicosanoid‐mediated responses, and the frequency and severity of

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01430.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Growing interest in nutritional intervention with n‐3 polyunsaturated fatty acids demands reliable analyses of these fatty acids and their corresponding eicosanoidsin vivoorex vivo. n‐3 polyunsaturated fatty acids are preferably assayed by capillary gas‐liquid chromatography after extraction of the lipid classes, their separation by chromatographic methods and conversion of the fatty acids to methylesters. n‐3 eicosanoids have to be separated from their arachidonic acid analogues by HPLC or by gas‐liquid chromatography and are then quantified by UV‐spectroscopy or mass‐spectrometry. Structure elucidation has to be performed by chemical reactions and by mass spectrometry. Antibodies for radioimmunoassays against n‐3 eicosanoids are no

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01431.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Although several studies have reported an inverse relationship between the dietary history of fish intake and the prospective incidence of death from coronary heart disease, it is unclear whether these results represent the effects of n‐3 fatty acids themselves or whether they merely reflect a more fundamental alteration in diet, such as a reduction in saturated fatty acids, n‐3 fatty acids alter platelet eicosanoid formation, replacing arachidonate derived thromboxane (Tx)A2with the biologically inert TxA3. However, they are a relatively inefficient approach to platelet inhibition. This is evident from results obtained in a model of coronary thrombosis followed by thrombolysis with tissue plasminogen activator (tPA). By contrast, high doses of n‐3 fatty acids (15 g day−1) significantly reduced blood pressure in mild hypertensives in a double‐blind, controlled study characterized by a prolonged run‐in period and adequate follow‐up. Fish oils inhibit the vascular proliferative response to injury in a variety of animal models, apparently independently of their effects on lipoprotein metabolism. Recent results imply that they may selectively interfere with the vascular expression of mitog

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01432.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Synthesis and secretion of triacylglycerol and cholesterol ester by cultured hepatocytes were highest in the presence of oleic, palmitic, stearic and linoleic acid, and lowest with eicosapentaenoic (EPA) and docosahexaenoic acid. Cellular formation and secretion of triacylglycerol and cholesterol ester were reduced by 50–80% in the presence of EPA in comparison with oleic acid. Reduced formation of triacylgycerol and cholesterol ester was also observed when EPA was given together with oleic acid. EPA caused higher incorporation of (3H)water into phospholipid and lower incorporation into triacylglycerol and cholesterol ester as compared with oleic acid. Rat liver microsomes incorporated EPA‐CoA into triacylglycerol and cholesterol ester to a lesser extent than oleoyl‐CoA. Decreased formation of triacylglycerol and cholesterol ester was also observed when EPA‐CoA was given together with oleoyl‐CoA, whereas palmitoyl‐CoA, stearoyl‐CoA, linolenoyl‐CoA and arachidonoyl‐CoA had no inhibitory effects. In conclusion, inhibition of acyl‐CoA: 1,2‐diacylglycerol acyltransferase and acyl‐CoA: cholesterol acyltransferase by EPA may be important for decreased hepatic synthesis and secretion of triacylglycero

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01433.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.From the Seven Countries Study and recent statistics from WHO and the OECD, it is clear that saturated fats, mainly dairy fats, are closely associated with the mortality rate from ischaemic heart disease (IHD). Consumption of alcohol, especially wine, but not polyunsaturated fats, seem to offer protection. Racial and other environmental factors do not seem to be confounding factors for that relationship as evaluated by studies in migrants, Japanese to USA, Southern Europeans to Australia, and in vegetarians in California. By contrast, very few trials using dietary polyunsaturated/saturated (P/S) ratios from 1.5‐2.5 vs 0.4‐0.7 have really prevented coronary death by diet modification. The only successful trial had a P/S ratio of 0.7. High P/S ratio increases platelet reactivity. Recent studies indicate that thrombosis and platelets play a more prominent role in IHD than expected. To decrease platelet activity and prevent IHD, a P/S ratio of 0.4‐0.7 should be pref

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01434.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.The original cross‐cultural comparisons between Greenland Eskimos and Danes and between Japan and Western countries suggested that a high fish intake was associated with low mortality rates from coronary heart disease. More comprehensive cross‐cultural studies, e.g. the Seven Countries Study showed that the saturated fat content of the diet is more important than the amount of fish in explaining differences in coronary heart disease mortality between countries. Cohort studies carried out in cultures with a low level of fish consumption showed that persons who eat fish once or twice a week had lower mortality rates from coronary heart disease than persons who did not eat fish. The results of the epidemiological studies carried out so far suggest that a diet low in saturated fat in combination with a low level of fish consumption may be of importance for coronary heart disease prevent

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01435.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.In animal models of arterial thrombosis, fish‐oil‐enriched diets have been shown to have an antithrombotic effect. There is strong evidence, however, that this only holds if the fish‐oil consumption is associated with a reduction of the saturated fat intake. In animal models of atherosclerosis the effect of a marine diet is not consistent. Although in some studies with cod‐liver oil (which is relatively low in saturated fatty acids) a beneficial effect is observed, studies with other, more saturated fish oils do not confirm this. The influence of fish‐oil consumption on some thrombotic complications of human atherosclerosis is not well documented. So far, the few results reported are not very promising, but it should remembered that this mainly concerns short‐term studies. Studies with respect to human fibrinolysis are equivocal. Evidence has been obtained that fish consumption may even have an adverse effect on certain aspects of the fibrinolytic process. The studies performed so far do not provide conclusive evidence as to the importance of fish‐ and fish‐oil‐enriched food for prevention and therapy of ischaemic cardiovascular disease. Further research is needed, especially with long‐term, high‐quality animal models. Moreover, long‐term, well‐controlled, prospective human intervention studies are required to investigate the effect of feasible fish(oil)‐enriched diets on morbidity and mortality of ischaemic ca

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01436.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Epidemiological, clinical and experimental studies suggest that dietary fatty acids belonging to two different families, the n‐6 and n‐3 fatty acids, might be important nutritional factors contributing to the natural history of atherothrombotic and inflammatory disorders. The relationship of these dietary fatty acids to plasma and cell membrane phospholipid composition, the eicosanoid system and related lipid mediators. and the mechanisms involved in cell stimulus‐response coupling (such as phospholipase C and phospolipase A2activation and Ca2+release) might reveal and modify processes underlying those disorders. It may thus open the development of new approaches to prevention and th

ISSN:0954-6820    

DOI:10.1111/j.1365-2796.1989.tb01437.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY