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Biomedical subjects

J Dyerberg

Publications and source records attributed to J Dyerberg.

At least 37 records · Page 2Linked to original sources
PubMed1997

Homocysteine in Greenland Inuits.

Patients with homozygous homocystinuria are at greatly increased risk for development of atherosclerosis and thrombosis (1). Elevated plasma levels of homocysteine (HCY) are caused by reduced enzymatic catabolism or reduced enzymatic remethylation of HCY, due to either hereditary enzyme defects or to nutritional deficiencies of vitamins functioning as cofactors. However, several recent studies have suggested that persons with mildly elevated plasma levels of HCY also are at increased risk for coronary heart disease. (2-4). There are some indications that dietary n-3 polyunsaturated fatty acids (PUFAs) may offer protection against coronary heart disease (5-6). Several mechanisms may be involved, including beneficial effects of n-3 PUFAs on plasma lipids, platelet and leukocyte reactivity, blood pressure and vasoreactivity (7). Interestingly, Olszewski el al. recently found HCY-levels to be lowered 36% in 15 type IIa or IIb hyperlipemic men by n-3 PUFA supplementation. A possible beneficial effect of n-3 PUFA on the incidence of coronary heart disease was initially suggested from studies in Greenland Inuits by our group (8). We therefore investigated plasma levels of homocysteine in a group of traditionally living Greenland Inuits with a diet consisting mainly of marine food and with a very high content of n-3 PUFAs.

Adult↗
PubMed1997

n-3 fatty acids do not decrease plasma endothelin levels in healthy individuals.

The effect of three different doses of n-3 polyunsaturated fatty acids (PUFA) on endothelin-1 (ET-1) was studied. Study 1 included 40 healthy volunteers randomized to a single supplement of 20 g of n-3 or n-6 PUFA. Plasma ET-1 was measured 14 h after ingestion, and no changes in plasma ET-1 after intake of n-3 PUFA were observed, compared to baseline values. In study 2, 32 subjects had 0.65 g of n-3 PUFA or a fat mixture per day for 12 weeks. No changes in plasma ET-1 were found after the oil supplements. Finally, 22 persons had 4 g of n-3 PUFA for 6 weeks. A significant increase in plasma ET-1 was seen in this group after the supplement. Thus, n-3 PUFAs do not lower plasma levels of ET-1, the most potent vasoconstrictor known.

Adult↗
PubMed1996

The apolipoprotein E polymorphism in Greenland Inuit in its global perspective.

Apolipoprotein E (apoE) genotypes were determined in Inuit population samples from Nuuk on the south-west coast of Greenland (n = 100) and from the Ammassalik region on the south-east coast (n = 78). The epsilon 2 allele was absent in the latter sample, and the epsilon 4 allele frequency was relatively high, about 23%. As in most other populations, mean plasma lipoprotein-related variables, except high-density lipoprotein (HDL) cholesterol, were higher in both Inuit men and women with epsilon 4 than in epsilon 3 epsilon 3 genotypes (P < 0.05 for triglycerides in men, and for non-HDL cholesterol and apolipoprotein B in women). The estimated apoE allele frequencies were combined with data from other studies of aboriginal peoples to outline a world map of apoE allele frequencies. A recent study of non-human primates suggests that epsilon 4, and not epsilon 3, is the ancestral allele in humans and we have used the map to generate additional hypotheses regarding the history of the apoE polymorphism in humans.

Alleles↗
PubMed1996

No effect of a very low dose of n-3 fatty acids on monocyte function in healthy humans.

There is some evidence that intake of sea food rich in n-3 polyunsaturated fatty acids (PUFA) may protect against coronary heart disease (CHD). Thus, even very low daily amounts of n-3 PUFA below 0.5 g have been reported to reduce the incidence of CHD, although it is unknown by what mechanisms this may occur. Monocytes are of major importance in atherogenesis, and we therefore studied the effect of a daily supplement with 0.65 g of n-3 PUFA for 12 weeks on monocyte function in a randomized placebo-controlled trial of 32 healthy subjects. No effect of dietary n-3 PUFA could be demonstrated on monocyte chemotaxis, on chemiluminescence, or on formation of cytokines and leukotriene B4 from activated monocytes.

Adult↗
PubMed1996

Increased plasma apolipoprotein (a) levels in IDDM patients with diabetic nephropathy.

OBJECTIVE: The relative mortality from cardiovascular disease (CVD) is increased 40-fold in IDDM patients suffering from diabetic nephropathy as compared with nondiabetic subjects on average. We assessed the potential contribution of dyslipidemia in general and elevated serum apolipoprotein (a) [apo(a)] in particular to CVD in nephropathic patients with IDDM. RESEARCH DESIGN AND METHODS: We investigated 199 IDDM patients with diabetic nephropathy and 192 normoalbuminuric IDDM patients matched for sex, age, diabetes duration, and BMI. RESULTS: The prevalence of CVD was 30 and 12% in patients with and without nephropathy, respectively (P < 0.001). The level of apo(a) was significantly higher in patients with nephropathy, 189 (20-2,350) U/l as compared with the normoalbuminuric group, 103 (20-1,940) U/l (P < 0.005). The prevalence of plasma apo(a) > 300 U/l (at-risk level for cardiovascular pathogenicity) was 38% (31-45) vs. 22% (16-28) in patients with and without nephropathy, respectively (P < 0.0005). In nephropathic patients, the prevalence of plasma apo(a) > 300 U/l was raised in patients with CVD (48%, 36-61%) as compared with patients without (34%, 26-42%) (P = 0.05). Furthermore, the serum concentrations of the following apolipoproteins and lipids were higher in patients with nephropathy as compared with normoalbuminuric patients: apoB 1.33 +/- 0.37 vs. 1.06 +/- 0.26 g/l; total cholesterol 5.6 +/- 1.2 vs. 4.8 +/- 0.9 mmol/l; and triglycerides 1.22 (0.31-9.87) vs. 0.77 (0.28-3.05) mmol/l, P < 0.0001. Multiple logistic regression analysis of cardiovascular risk factors revealed that plasma apo(a) concentration > 300 U/l is an independent risk factor for coronary heart disease, odds ratio 1.86 (1.03-3.36) (P < 0.05). CONCLUSIONS: Dyslipidemia and raised plasma concentrations of apo(a), particularly > 300 U/l, may contribute to the enhanced morbidity and mortality from CVD characteristically observed in IDDM patients with diabetic nephropathy.

Adult↗
PubMed1995

The influence of trans fatty acids on health: a report from the Danish Nutrition Council.

Trans fatty acids constitute 0-30% of the fat in Danish margarines, most in industry and bakery margarines and usually less in table margarine. The trans fatty acids make margarines more solid at room temperature and therefore provide an economical storage advantage. In British and U.S. reports from 1984-1989, the trans fatty acids were more or less acquitted of unhealthy effects. During the last 5-6 years, however, a series of new studies has been published regarding both the connection between the consumption of trans fatty acids and the occurrence of coronary heart disease and the impact on the lipoprotein level in plasma. Studies suggest that the consumption of trans fatty acids from margarine is equally, or perhaps more, responsible for the development of arteriosclerosis than saturated fatty acids. In addition, it is now clear that both the fetus and the breast-fed baby are exposed to trans fatty acids in relation to the mother's consumption. A couple of recent studies suggest a possible restrictive influence of the trans fatty acids on the weight of the fetus. The average consumption of trans fatty acids from margarine in Denmark in 1991 was approximately 2.5 g/day per person. For about 150,000 adult Danes, the consumption is assumed to be more than 5 g/day per person. On this basis, the Danish Nutrition Council recommend that the consumption of trans fatty acids is reduced as much as possible. This can be done by reducing the fat content in food and by reducing the trans fatty acid content in all Danish margarine products to 5% or less. Thereafter, the group of adult Danes, including pregnant and breast-feeding women, with a large consumption of margarine and margarine-containing products, will on average only consume 2 g of vegetable trans fatty acids/day. This corresponds to the consumption in the low-risk groups in the above-mentioned epidemiological studies. In addition, the Danish Nutrition Council encourage the producers of margarines to make products that can be marketed as 'free of trans fatty acids'.

Adult↗
PubMed1995

The effect of n-3 fatty acids on neutrophil chemiluminescence.

The effect of dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs) on the production of free oxygen radicals from activated neutrophils was investigated in healthy subjects, using chemiluminescence. In the first study 22 persons were give 4 g n-3 PUFAs daily for 6 weeks. There was a median reduction of chemiluminescence from neutrophils stimulated with opsonized zymosan of 37% (p < 0.001). The median content of eicosapentaenoic acid in platelets, used as an indicator for cellular fatty acid profile, increased from 0.70 to 2.80% (p < 0.001), and there was a significant negative correlation between the chemiluminescence signal and the content of eicosapentaenoic acid in platelets (p < 0.001). In a second, low-dose study 24 persons were allocated to daily supplementation with either 0.65 g n-3 PUFAs or with a control oil for 6 weeks. Compared to the control group there was a median reduction of 38 and 44% in chemiluminescence from neutrophils stimulated with opsonized zymosan and phorbol,12-myristate,13-acetate (PMA), respectively. Neither of these differences, however, was statistically significant. These findings lend support for a possible role of n-3 PUFAs in the management of inflammatory disorders.

Adult↗
PubMed1994

[The effect on health of dietary antioxidants and antioxidant supplements].

Reactive free oxygen radicals are formed in the reactions involved in normal cell metabolism. This formation is closely regulated e.g. by dietary antioxidants. Present knowledge suggests that an imbalance, with surplus of free radicals, can play a role in the pathogenesis of certain types of cancer, atherosclerosis, and cataract. A number of epidemiological studies have demonstrated a reduced risk of developing these diseases in persons who consume a diet with a high content of vegetables and fruit, which contains large quantities of the antioxidants: beta-carotene, vitamins C and E. Intervention studies, using supplements of these antioxidants, have so far not been able to show a beneficial effect. The apparently protective effect of fruit and vegetables may be due to other active ingredients. In Denmark the average intake of vegetables and fruit is low, and it is estimated that an increased consumption of these foods could reduce the occurrence of certain cancer types and atherosclerosis. In contrast, there is no evidence that antioxidant supplements would provide protection against disease, and their safety remains to be established.

Antioxidants↗
PubMed1994

[Significance of trans-fatty acids for health].

Trans fatty acids make up 0-30% of the fatty acids in Danish margarines. The intake of trans fatty acids from margarine in Denmark was in 1991 on average about 2.5 gram/person/day, and for about 150,000 Danes more than 5 gram/person/day. Several recent case-control studies and a large cohort study as well as clinical ward studies suggest that the intake of trans fatty acids enhances atherogenesis to the same extent or possibly even more than saturated fatty acids. In addition a few studies suggest that the intake of trans fatty acids by the pregnant mother impairs growth of the human foetus. On this background it seems reasonable to reduce the intake of trans fatty acids as much as possible. This could be implemented by a reduction in the fat content of the diet together with a reduction of trans fatty acid content to less than 5% in all margarines. This would ensure that Danes--including pregnant and nursing women--with a high intake of margarine on average consume less than 2 gram of trans fatty acids of vegetables origin per day. This amount corresponds to intake in low risk groups in several studies.

Denmark↗
PubMed1994

[Fish oils and rheumatoid arthritis. A randomized and double-blind study].

The effect of dietary supplementation with n-3 polyunsaturated fatty acids (n-3 PUFA) on disease variables in patients with active rheumatoid arthritis was evaluated in a multicentre, randomized and double blind study. Fifty-one patients with active rheumatoid arthritis were included from three Danish hospital Departments of Rheumatology. The patients were allocated to 12 weeks of treatment with either six n-3 PUFA capsules (3.6 g) or six capsules with a fat composition averaging the Danish diet. Small but significant improvements in morning stiffness, joint tenderness and C-reactive protein were observed. There were no serious side-effects. Dietary supplementation with n-3 PUFA in patients with active rheumatoid arthritis has a modest effect on three out of eight disease variables, without effect on other traditional parameters for monitoring disease activity.

Arthritis, Rheumatoid↗
PubMed1994

The acute effects of a single very high dose of n-3 fatty acids on plasma lipids and lipoproteins in healthy subjects.

Forty healthy volunteers were allocated in a double blind, randomized study to receive either 20 g of n-3 polyunsaturated fatty acids (PUFA) or 20 g of n-6 PUFA at their evening meal. The effect on plasma lipids and lipoproteins of this single dose of fish oil vs. corn oil was studied the next morning, 14 h after ingestion. Plasma triglycerides and very low density lipoprotein-cholesterol significantly decreased (33%) after n-3 PUFA (P < 0.001), and significantly (P < 0.01) more than after intake of n-6 PUFA. The decrease in plasma triglycerides after n-3 PUFA ingestion was more pronounced in subjects with higher baseline levels of triglycerides (P < 0.001). Total cholesterol decreased after both supplements, but did not differ between the supplements. Low density lipoprotein-cholesterol did not change, and high density lipoprotein-cholesterol significantly decreased in subjects given n-3 PUFA compared to baseline, but not when compared to subjects receiving n-6 PUFA. In conclusion, we have shown that a single very high dose of n-3 PUFA has a pronounced hypotriglyceridemic effect, which is directly related to the initial plasma level.

Adult↗
PubMed1994

Omega-3 fatty acids. Current status in cardiovascular medicine.

Omega-3 polyunsaturated fatty acids (PUFA) reduce fasting and postprandial triglycerides, decrease platelet and leucocyte reactivity, and may slightly decrease blood pressure. Omega-3 PUFA may also beneficially influence vessel wall characteristics and blood rheology. Furthermore, these compounds have been shown to inhibit ventricular tachyarrhythmias in animals. Omega-3 PUFA may impair fibrinolysis and could lead to increased oxidation of lipoproteins. Potential adverse effects must not be neglected, but should be viewed in light of the beneficial effects of these agents. Clinical studies investigating the effects of dietary omega-3 PUFA in the prevention and treatment of cardiovascular disease (CVD) are beginning to emerge. The results have offered some promise, but further studies are needed to define the role of these agents in CVD. Long term trials and studies using omega-3 PUFA as adjuvants to conventional therapy in patients with coronary artery disease, hyperlipidaemia and hypertension may be of particular interest.

Animals↗