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Biomedical subjects

J Dyerberg

Publications and source records attributed to J Dyerberg.

At least 127 records · Page 7Linked to original sources
PubMed1983

The effect of N-6 and N-3 polyunsaturated fatty acids on hemostasis, blood lipids and blood pressure.

Diverging results from studies of marine oil supplementation to western diets initiated the undertaking of a double-blind crossover study, with administration to healthy volunteers for 4 weeks of either 10 g of fish oil or 10 g of vegetable oil. Each oil containing approx. 40% of n-3 and n-6 polyunsaturated fatty acids (PUFA) respectively. During the n-3 PUFA period, systolic blood pressure, plasma total lipids, triglycerides and VLDL concentrations fell significantly whereas plasma antithrombin-III (AT-III) rose. Cutaneous bleeding time increased significantly. In contrast only AT-III rose during the n-6 PUFA feeding, however, more marked than during the n-3 oil period. It is concluded that a n-3 PUFA oil supplement to the western diet exerts an effect that generally is considered as beneficial in terms of the risk of developing cardiovascular diseases. It is in this respect superior to that of n-6 PUFA, stressing the necessity of a more differentiated approach to advice on dietary PUFA enrichment than presently is exerted.

Adult↗
PubMed1982

A hypothesis on the development of acute myocardial infarction in Greenlanders.

Non-emigrated Greenlanders have a low incidence of acute myocardial infarction (AMI), when compared with age- and sex adjusted death rates for ischemic heart disease in western countries. We find that Greenlanders have plasma lipid levels corresponding to favourable risk factor levels for AMI. This can be attributed to their diet, rich in n-3 polyunsaturated fat. This diet further supplies eicosapentaenoic acid which influence platelet vessel wall function in an antithrombotic direction. A high level of plasma-antithrombin-III, raising the anticoagulant activity of the blood, in combination with a genetically high activation threshold for the complement system may further contribute to the resistancy against thrombo-embolic disorders. Bleeding tendency, and susceptibility to infection disorders may be the possible draw-backs. Our data are framed into a hypothesis combining the indications of genetic predispositions and the evidence of exogenous protective factors, inflicting a coherent enhancement of nonsusceptibility to vascular ischemic catastrophies.

Antithrombin III↗
PubMed1982

Antithrombin III and dietary intake of polyunsaturated fatty acids.

Immunoreactive antithrombin III and antithrombin III activity was found to be significantly higher in 81 Greenland Eskimos than in 50 Caucasian Danes. Sixteen Eskimos who had emigrated to Denmark had significantly lower immunoreactive antithrombin III levels than the Greenland Eskimos, though higher than the Danes. The immunoreactive antithrombin III increased significantly while the increase in antithrombin III activity was insignificant in 20 male Caucasian Danes upon 3 weeks supplementation of the diet with 10 ml daily of a cod liver oil concentrate. The high antithrombin III level in the Eskimos may at least partly be a consequence of a high dietary intake of polyunsaturated fatty acids. It may also play a role for the low incidence of thrombosis apparently found in Greenland Eskimos.

Adult↗
PubMed1981

Platelet - vessel wall interaction: influence of diet.

The interaction of platelets with the vessel wall is influenced by the diet. Of major importance is the dietary polyunsaturated fatty acids (PUFA). Epidemiological evidence from Greenland Eskimos with low incidences of acute myocardial infarction has drawn attention to the role of the n - 3 PUFA family. Experiments in vitro have demonstrated an anti-aggregatory effect of eicosapentaenoic acid (EPA). However, EPA does not inhibit vascular prostacyclin production. Antiaggregatory substances generated from EPA have not yet been demonstrated in vivo. Studies in vivo in both animals and humans have demonstrated an antithrombotic effect of EPA. In a study where volunteers were given 6 g EPA per day for 3 weeks, moderate decreases in collagen-induced and ADP-induced platelet aggregation, lower thromboxane B2 (TXB2) synthesis and prolongation of bleeding time were found. These observations indicate the dietary factors modulate the interaction of platelets and the vessel wall. Dietary advice aiming at lowering the incidence of ischaemic diseases must include this aspect. This necessitates a re-evaluation of advice hitherto given to the population in general.

Blood Platelets↗
PubMed1981

Human umbilical blood vessel converts all cis-5, 8, 11, 14, 17 eicosapentaenoic acid to prostaglandin I3.

All cis-5, 8, 11, 14, 17 eicosapentaenoic acid (EPA) is presently being evaluated for dietary prophylactic use in thrombo-embolic disorders. EPA inhibits the production of TXA2 and platelet aggregation. We here present results demonstrating that human umbilical arteries convert 14c-EPA to a substance that in aqueous solutions decomposes to 14C-delta 17-6-keto-PGF1 alpha . The conversion rate in rat aortic tissue was found substantially lower. These results in combination with earlier data indicating that EPA does not influence the conversion of arachidonic acid (AA) into PGI2 in human vascular tissue, encourage further research along the lines initiated by the findings of high EPA/AA ratio and low incidence of myocardial infarction in Greenland Eskimos.

6-Ketoprostaglandin F1 alpha↗
PubMed1981

Personal reflections on the incidence of ischaemic heart disease in Oslo during the Second World War.

The dietary changes in Norway and especially in Oslo during the Second World War, with reduced fat intake and increased consumption of fish and fish products, was paralleled by a reduced incidence of and mortality from IHD. This was probably caused to a high degree by reduced platelet aggregability leading to a reduced tendency to thrombosis. We suggest that the mechanism behind this reduction was a changed balance between pro- and anti-aggregatory prostaglandins towards the anti-aggregatory side, caused by eicosapentaenoic acid from fish lipids. Furthermore, hypocholesterolaemia due to reduced fat intake and increased consumption of polyunsaturated fatty acids certainly contributed to this effect by reducing platelet aggregability.

Coronary Disease↗
PubMed1980

The composition of the Eskimo food in north western Greenland.

In the winter of 1976 an examination of the composition of Eskimo food was carried out in north western Greenland. Duplicate specimens of diets collected from 50 adults, equal numbers of males and females, were analyzed for water, ash, protein, fat, individual fatty acids, cholesterol, and carbohydrate. The results are compared with those of typical Danish diets. Seal and the fish are predominant Eskimo food. Marked differences between Eskimo and Danish food were found. The Eskimo diets were richer in polyunsaturated fatty acids, the ratio to saturated fatty acids was 0.84 as compared with 0.24 in Danes. The polyunsaturated fatty acids were predominantly of the linolenic class (n-3) in Eskimos and the linoleic class (n-6) in Danes. Monoenes other than palmitoleic and oleic acids were high in Eskimo diets, but negligible in Danish. The results are related to previous examinations of the plasma lipids in Eskimos. The rarity of ischemic heart disease in Greenland Eskimos may partly be explained by the antithrombotic effect of the long-chained polyunsaturated fatty acids, especially eicosapentaenoic acid prevalent in diets rich in marine oils.

Adult↗