Distribution of Coronary Atherosclerosis and its Correlation to Metabolic Risk Factors and Femoral Atherosclerosis

Coronary angiography was performed in 216 men of whom 78 also had a cine-angiogram of one femoral artery. Stenoses of the coronary arteries were measured with a pair of calipers and the femoral angiograms were computer-analysed. The patients were divided into 2 groups according to whether the bulk of the coronary stenoses affected the central or the peripheral part of the coronary arteries. The groups were investigated regarding differences in lipid and metabolic risk factors. Coronary atherosclerosis was most often found in the proximal part of the right coronary arteries. No significant correlation between coronary and femoral atherosclerosis was found. Previous myocardial infarction was associated with more coronary artery stenosis (p < 0.003). No pattern of risk factors was found to discriminate between central and peripheral coronary atherosclerosis.

Transfer of omega-3 fatty acids across the blood-brain barrier after dietary supplementation with a docosahexaenoic acid-rich omega-3 fatty acid preparation in patients with Alzheimer's disease: the OmegAD study

OBJECTIVE

Little is known about the transfer of essential fatty acids (FAs) across the human blood-brain barrier (BBB) in adulthood. In this study, we investigated whether oral supplementation with omega-3 (n-3) FAs would change the FA profile of the cerebrospinal fluid (CSF).

METHODS

A total of 33 patients (18 receiving the n-3 FA supplement and 15 receiving placebo) were included in the study. These patients were participants in the double-blind, placebo-controlled randomized OmegAD study in which 204 patients with mild Alzheimer's disease (AD) received 2.3 g n-3 FA [high in docosahexaenoic acid (DHA)] or placebo daily for 6 months. CSF FA levels were related to changes in plasma FA and to CSF biomarkers of AD and inflammation.

RESULTS

At 6 months, the n-3 FA supplement group displayed significant increases in CSF (and plasma) eicosapentaenoic acid (EPA), DHA and total n-3 FA levels (P < 0.01), whereas no changes were observed in the placebo group. Changes in CSF and plasma levels of EPA and n-3 docosapentaenoic acid were strongly correlated, in contrast to those of DHA. Changes in DHA levels in CSF were inversely correlated with CSF levels of total and phosphorylated tau, and directly correlated with soluble interleukin-1 receptor type II. Thus, the more DHA increased in CSF, the greater the change in CSF AD/inflammatory biomarkers.

CONCLUSIONS

Oral supplementation with n-3 FAs conferred changes in the n-3 FA profile in CSF, suggesting transfer of these FAs across the BBB in adults.

Plasma lipid fatty acid composition, desaturase activities and insulin sensitivity in Amerindian women

BACKGROUND AND AIMS

Two Amerindian populations--Shuar women living in the Amazonian rain forest under traditional conditions and urbanized women in a suburb of Lima were studied. The fatty acid composition in plasma lipids and the relationships between fatty acid composition and metabolic variables were studied, as well as in a reference group of Swedish women.

METHODS AND RESULTS

Fasting plasma was used for analyses of glucose, insulin, leptin and fatty acid composition. Women in Lima had more body fat, higher fasting insulin and leptin and lower insulin sensitivity than the Shuar women, who had insulin sensitivity similar to Swedish women. Shuar women had very high proportions (mean; SD) of palmitoleic (13.2; 3.9%) and oleic (33.9; 3.7%) acids in the plasma cholesteryl esters with very low levels of linoleic acid (29.1; 6.1 3%), as expected on a low fat, high carbohydrate diet. The estimated activity of delta 9 (SCD-1) desaturase was about twice as high in the Shuar compared with Lima women, suggesting neo lipogenesis, while the delta 5 desaturase activity did not differ. The Lima women, as well as the Swedish, showed strong positive correlations between SCD-1 activity on the one hand and fasting insulin and HOMA index on the other. These associations were absent in the Shuar women.

CONCLUSIONS

The high SCD-1 activity in the Shuar women may reflect increased lipogenesis in adipose tissue. It also illustrates how a low fat diet rich in non-refined carbohydrates can be linked to a good metabolic situation.

Replacing dairy fat with rapeseed oil causes rapid improvement of hyperlipidaemia: a randomized controlled study

BACKGROUND

Rapeseed oil (RO), also known as canola oil, principally contains the unsaturated fatty acids 18:1n-9, 18:2n-6 and 18:3n-3 and may promote cardiometabolic health.

OBJECTIVE

To investigate the effects on lipoprotein profile, factors of coagulation and insulin sensitivity of replacing a diet rich in saturated fat from dairy foods (DF diet) with a diet including RO-based fat (RO diet).

DESIGN

During a 2×3-week randomized, controlled, cross-over trial, 20 free-living hyperlipidaemic subjects were provided with isocaloric test diets that differed in fat composition alone. Blood lipoprotein profile, coagulation and fibrinolytic factors and insulin sensitivity (euglycaemic clamp) were determined before and after the dietary intervention.

RESULTS

All subjects completed the study, and compliance was high according to changes in serum fatty acids. The RO diet, but not the DF diet, reduced the levels of serum cholesterol (-17%), triglycerides (-20%) and low-density lipoprotein cholesterol (-17%), cholesterol/high-density lipoprotein (HDL) cholesterol ratio (-21%), apolipoprotein (apo) B/apo A-I ratio (-4%) and factor VII coagulant activity (FVIIc) (-5%) from baseline. These changes were significantly different between the diets (P=0.05 to P<0.0001), except for FVIIc (P=0.1). The RO diet, but not the DF diet, modestly increased serum lipoprotein(a) (+6%) and tended to increase the glucose disappearance rate (K-value, +33%). HDL cholesterol, insulin sensitivity, fibrinogen and tissue plasminogen activator inhibitor-1 levels did not change from baseline or differ between the two diets.

CONCLUSIONS

In a diet moderately high in total fat, replacing dairy fat with RO causes a rapid and clinically relevant improvement in serum lipoprotein profile including lowering of triglycerides in hyperlipidaemic individuals.

Essential fatty acid status in teenage girls with eating disorders and weight loss

AIM

To explore the relationship between essential fatty acids (FA) and weight changes in adolescent girls with eating disorders (ED).

METHODS

Blood samples were obtained from 220 girls with ED and 39 healthy controls. The girls with ED were 15.3 ± 1.5 years of age and weighed 49.8 ± 8.7 kg (BMI 18.3 ± 2.8 kg/m(2)) after a weight loss of 6.8 ± 6.4 kg. FA were analysed in plasma phospholipids (PPL) and erythrocyte membranes (ERY).

RESULTS

The proportions of saturated and monounsaturated FA were increased during weight loss, while linoleic acid (18:2ω6) was decreased. The proportions of eicosapentanoic acid (EPA) (20:5ω3) and docosahexanoic acid (DHA) (22:6ω3) in PPL and ERY did not differ from controls. The activity of stearoyl-CoA-desaturase was increased as evidenced by an increased product/precursor ratio and correlated with the rate of weight loss. The activities of delta-6-desaturase and delta-5-desaturase did not differ from controls. The rate of weight loss was inversely correlated with delta-6-desaturase and directly correlated with delta-5-desaturase.

CONCLUSION

The FA profile indicates low-fat intake, fat mobilization from stores and an increased conversion of essential FA at the delta-5-desaturase step during weight loss in adolescent girls with ED. Normal levels of EPA and DHA were maintained.

Effects of a healthy Nordic diet on cardiovascular risk factors in hypercholesterolaemic subjects: a randomized controlled trial (NORDIET)

OBJECTIVE

the aim of this study was to investigate the effects of a healthy Nordic diet (ND) on cardiovascular risk factors.

DESIGN AND SUBJECTS

in a randomized controlled trial (NORDIET) conducted in Sweden, 88 mildly hypercholesterolaemic subjects were randomly assigned to an ad libitum ND or control diet (subjects' usual Western diet) for 6 weeks. Participants in the ND group were provided with all meals and foods. Primary outcome measurements were low-density lipoprotein (LDL) cholesterol, and secondary outcomes were blood pressure (BP) and insulin sensitivity (fasting insulin and homeostatic model assessment-insulin resistance). The ND was rich in high-fibre plant foods, fruits, berries, vegetables, whole grains, rapeseed oil, nuts, fish and low-fat milk products, but low in salt, added sugars and saturated fats.

RESULTS

the ND contained 27%, 52%, 19% and 2% of energy from fat, carbohydrate, protein and alcohol, respectively. In total, 86 of 88 subjects randomly assigned to diet completed the study. Compared with controls, there was a decrease in plasma cholesterol (-16%, P < 0.001), LDL cholesterol (-21%, P < 0.001), high-density lipoprotein (HDL) cholesterol (-5%, P < 0.01), LDL/HDL (-14%, P < 0.01) and apolipoprotein (apo)B/apoA1 (-1%, P < 0.05) in the ND group. The ND reduced insulin (-9%, P = 0.01) and systolic BP by -6.6 ± 13.2 mmHg (-5%, P < 0.05) compared with the control diet. Despite the ad libitum nature of the ND, body weight decreased after 6 weeks in the ND compared with the control group (-4%, P < 0.001). After adjustment for weight change, the significant differences between groups remained for blood lipids, but not for insulin sensitivity or BP. There were no significant differences in diastolic BP or triglyceride or glucose concentrations.

CONCLUSIONS

a healthy ND improves blood lipid profile and insulin sensitivity and lowers blood pressure at clinically relevant levels in hypercholesterolaemic subjects.

Adipose tissue fatty acids and insulin sensitivity in elderly men

AIMS/HYPOTHESIS

Dietary fatty acids may affect insulin sensitivity. Adipose tissue fatty acid composition partly reflects long-term dietary intake, but data from large studies regarding relationships with insulin sensitivity are lacking. We aimed to determine the association between adipose tissue fatty acids and insulin sensitivity in elderly Swedish men.

METHODS

In a cross-sectional analysis of the community-based Uppsala Longitudinal Study of Adult Men (n = 795, mean age 71 years), adipose tissue biopsies were obtained and fatty acid composition was determined by gas-liquid chromatography. Insulin sensitivity was measured directly by a euglycaemic clamp.

RESULTS

Palmitic acid (16:0), the major saturated fatty acid (SFA) in the diet and in adipose tissue, was negatively correlated with insulin sensitivity (r = -0.14), as were 16:1 n-7 (r = -0.15), 20:3 n-6 (r = -0.31), 20:4 n-6 (r = -0.38), 22:4 n-6 (r = -0.37) and 22:5 n-3 (r = -0.24; p < 0.001 for all). Some minor SFAs were positively correlated; 12:0 (r = 0.46), 14:0 (r = 0.32), 17:0 (r = 0.21) and 18:0 (r = 0.41; p < 0.001 for all), as were essential polyunsaturated fatty acids (PUFAs) 18:2 n-6 (r = 0.10, p < 0.01) and 18:3 n-3 (r = 0.16, p < 0.001). Docosahexaenoic acid (22:6 n-3) was negatively correlated (r = -0.11, p < 0.01), whereas eicosapentaenoic acid (20:5 n-3) was not (r = -0.02, NS). Most associations diminished or disappeared in lean individuals, indicating an effect of obesity.

CONCLUSIONS/INTERPRETATION

Adipose tissue enriched with palmitic acid and depleted of essential PUFAs is associated with insulin resistance. The positive association between minor SFAs and insulin sensitivity merits further investigation.

Metabolic Effects of Pindolol and Propranolol in a Double-Blind Cross-Over Study in Hypertensive Patients

Metabolic effects of pindolol and propranolol were investigated in a randomised study of double-blind, double-dummy design in 39 Caucasians with newly detected hypertension. Each active treatment period was 6 months long. A euglycaemic hyperinsulinaemic clamp test was done to measure insulin sensitivity, and i.v. glucose tolerance was investigated with insulin determinations. Lipoprotein concentrations were quantified and lipoprotein lipase activities were determined in muscle and adipose tissue and in plasma after heparin injection. The blood pressure was significantly reduced by both regimes. The insulin sensitivity index was decreased by 34% during propranolol treatment and by 17% during pindolol treatment. The insulin concentrations in plasma were elevated at the end of the i.v. glucose tolerance test but were not high enough to compensate for the insulin resistance, so HbA1c and glucose concentrations were increased. A significant reduction of lipoprotein lipase activity in skeletal muscle during propranolol treatment probably explains the pronounced increase in serum triglyceride concentration during propranolol treatment despite lower free fatty acids and higher lipoprotein lipase activity in adipose tissue. These changes of lipoprotein lipase activity were not correlated to the changes in insulin sensitivity. In summary, the metabolic effects were significantly less pronounced with pindolol than with propranolol, which probably can be ascribed to the agonistic effect of pindolol on beta 2 adrenoceptors.

Plasma antioxidant capacity among middle‐aged men: The contribution of uric acid

OBJECTIVE

Although assays of plasma antioxidant capacity encompass interactions between various antioxidants, uric acid concentration can exert a predominant effect on results. Therefore, individual differences in uric acid concentration may explain a many of the differences in antioxidant capacity. The objective of this study was to measure the antioxidant capacity of plasma samples with and without uric acid in order to provide more information about how the concept of antioxidant capacity could be applied.

MATERIAL AND METHODS

Antioxidant capacity was measured using an enhanced chemiluminescence assay, and uric acid was removed from the samples using uricase.

RESULTS

Antioxidant capacity was positively correlated with uric acid concentration, body mass index, waist circumference, abdominal sagittal diameter and the concentrations of insulin and triglycerides. These correlations were not evident when uric acid was eliminated from the sample, but antioxidant capacity was correlated with lipid concentration; this may partly reflect tocopherols that are transported by lipid molecules.

CONCLUSIONS

The significance of the contribution of uric acid to the antioxidant capacity could differ according to the type of study. Antioxidant capacity measurements in cross-sectional studies may be presented both with and without the contribution of uric acid, because the absence of such data complicates interpretation of results when different populations are compared.

Improved metabolic control after supplemented fasting in overweight type II diabetic patients

Twenty obese type II diabetes patients were treated in a metabolic ward during 4 weeks with a very low calorie regimen (200 kcal/day). They were given dietary advice and reexamined 3 months after discharge. Mean body weight decreased by 10 kg during fasting, blood glucose was normalized, urinary glucose disappeared and the K-value at i.v. glucose tolerance test increased. Fasting serum insulin concentrations decreased by 54%. Serum triglycerides (TG) decreased by 65%, serum cholesterol (Chol) by 28% and high density lipoprotein (HDL) Chol by 14%. Three months later, only serum TG remained significantly decreased (-47%) while HDL Chol was significantly higher than on admission (+11%). Fasting blood glucose remained significantly lower (-25%) with a low urinary glucose excretion. Supplemented fasting appears to be a safe and useful tool in the treatment of obese type II diabetics. It causes, at least during a limited follow-up period, a significant improvement in glucose control and lipoprotein metabolism in spite of a concomitant reduction of the antidiabetic medication.

Effects of dietary supplementation with n-6 and n-3 long-chain polyunsaturated fatty acids on serum lipoproteins and platelet function in hypertriglyceridaemic patients

Twenty-seven patients with hypertriglyceridaemia were given dietary supplementation either with evening primrose oil rich in gammalinolenic acid (GLA, 18:3 n-6) (n = 13) or a marine oil concentrate containing n-3 fatty acids (n = 14) in a double-blind cross-over design during 8 + 8 weeks with olive oil as placebo. During GLA supplementation, increases in GLA and dihomogammalinolenic acid (20:3 n-6) were found in plasma lipid esters and platelet phospholipids, whereas platelet function and serum lipoproteins were unaffected. During supplementation with n-3 fatty acids there was a significant decrease in triglycerides in all lipoprotein fractions with a slight increase in high density lipoprotein and low density lipoprotein cholesterol. A marked increase in the long-chain n-3 fatty acids was found both in plasma and platelets, mainly at the expense of the n-6 fatty acids. No pronounced effects on platelet reactivity could be demonstrated. Our results confirm a triglyceride-lowering effect of n-3 fatty acids, whereas no such effect of GLA could be demonstrated.

Serum lipoprotein and apolipoprotein concentrations in patients with hyperthyroidism and the effect of treatment with carbimazole

Forty patients, 32 women and 8 men, with hyperthyroidism were investigated concerning serum lipoprotein lipid and apolipoprotein concentrations before, during and after treatment with carbimazole to euthyroidism. During the hyperthyroid condition the patients had significantly lower serum concentrations of low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol. The serum lipoprotein triglyceride concentrations were within the normal ranges. During treatment to euthyroidism the low serum concentrations of LDL and HDL cholesterol increased to normal values. LDL and HDL concentrations increased in the female patient group by 46 +/- 12 and 25 +/- 9% and in the male patient group by 50 +/- 12 and 19 +/- 11%, respectively. During treatment serum apolipoprotein B and A-I concentrations increased significantly in females by 58 +/- 9 and 18 +/- 5% and in males by 60 +/- 9 and 13 +/- 8%, respectively.

Serum and dietary beta-carotene and alpha-tocopherol and incidence of type 2 diabetes mellitus in a community-based study of Swedish men: report from the Uppsala Longitudinal Study of Adult Men (ULSAM) study

AIMS/HYPOTHESIS

To investigate the association of serum concentrations and dietary intake of beta-carotene and alpha-tocopherol with type 2 diabetes incidence.

METHODS

Serum beta-carotene, alpha-tocopherol, lifestyle factors (BMI, physical activity and smoking) and metabolic factors (insulin sensitivity [homeostasis model assessment], acute insulin response and impaired fasting glucose) were analysed in 846 50-year-old non-diabetic Swedish men (participants in the Uppsala Longitudinal Study of Adult Men). Diabetes was identified in 245 participants at reinvestigations after 10, 20 and 27 years. At the 20 year reinvestigation, dietary intake of beta-carotene and alpha-tocopherol, insulin sensitivity (euglycaemic-hyperinsulinaemic clamp) and insulin secretion (early insulin response in OGTT) were determined.

RESULTS

The highest tertile of serum beta-carotene at age 50 (>0.335 mumol/l) was associated with 59% lower risk of diabetes during follow-up compared with the lowest tertile (<0.210 mumol/l) after adjustment for lifestyle and metabolic factors (p < 0.01). The highest tertile of lipid-corrected serum alpha-tocopherol at age 50 (>3.67 mumol/mmol) was associated with 46% lower risk of diabetes compared with the lowest tertile (<3.25 mumol/mmol) independently of metabolic factors (p < 0.05). Moreover, lower serum beta-carotene and alpha-tocopherol concentrations were independently associated with impaired insulin sensitivity (p < 0.001), but not with early insulin response, in a subsample of non-diabetic individuals 20 years later. Dietary intake of beta-carotene and alpha-tocopherol independently predicted type 2 diabetes during 7 years of follow-up.

CONCLUSIONS/INTERPRETATION

Serum concentrations and dietary intakes of beta-carotene and alpha-tocopherol independently predicted insulin resistance and type 2 diabetes incidence during 27 years of follow-up in a community-based study of men. This result supports the importance of impaired antioxidant status for the development of insulin resistance and type 2 diabetes.

Serum phospholipid and cholesteryl ester fatty acids and estimated desaturase activities are related to overweight and cardiovascular risk factors in adolescents

AIM/HYPOTHESIS

The objective of this study was to describe the relation of serum fatty acids and desaturase activity (DA) to overweight, insulin sensitivity and cardiovascular disease (CVD) risk factors in adolescents.

METHODS

The relations of % serum phospholipid (PL) and cholesteryl ester (CE) fatty acids and estimated DA with CVD risk factors were examined in 264 adolescents (average age 15 years). Fatty acids were determined by gas liquid chromotography. Surrogate measures of DA were expressed as ratios of serum fatty acids: Delta9 DA=16:0/16:1; Delta6 DA=20:3,n6/18:2,n6 (PL) or 18:3,n6/18:2,n6 (CE); and Delta5 DA=20:4,n6/20:3,n6. Spearman partial correlations of fatty acids (%) and DA ratios with CVD risk factors were reported, adjusting for age, sex, race, Tanner stage, energy intake and physical activity.

RESULTS

Overweight adolescents compared to normal weight had more adverse levels of CVD risk factors, composition of PL and CE fatty acids in serum, and Delta6 DA and Delta5 DA ratios. Linoleic acid was inversely related to body mass index (BMI), waist circumference and triglycerides (P

CONCLUSION

These findings support those observed in adults, that factors, such as type of dietary fat, physical activity, and obesity, may influence fatty acid metabolism and are important in the development of adverse CVD risk factors as early as adolescence.

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Key Words Collapse

MESH Headings

• Adolescent
• Body Mass Index
• Cardiovascular Diseases/etiology
• Cholesterol Esters/blood
• Fatty Acid Desaturases/blood
• Fatty Acids/blood
• Female
• Humans
• Insulin Resistance
• Male
• Overweight/blood
• Overweight/physiopathology
• Phospholipids/blood
• Risk Factors
• Waist Circumference

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Grants

• M01 RR000400 NCRR NIH HHS
• R01 HL052851-13 NHLBI NIH HHS
• MO1RR00400 NCRR NIH HHS
• HL52851 NHLBI NIH HHS
• R01 HL052851 NHLBI NIH HHS

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A high activity index of stearoyl-CoA desaturase is associated with increased risk of fracture in men

The activity index of stearoyl-CoA desaturase (SCD), a key enzyme in lipogenesis, was associated with increased risk of fracture in a longitudinal population-based cohort of men. This indicates that elevated levels of endogenous lipogenesis increase the risk of fracture and suggest a role for saturated fat in the pathogenesis of osteoporosis.

INTRODUCTION

Osteoblasts and marrow adipocytes are derived from a common mesenchymal progenitor, and experimental studies have indicated that increased adipogenesis can occur at the expense of osteoblasts, leading to bone loss. Stearoyl-CoA desaturase (SCD) converts saturated to monounsaturated fatty acids and is a key enzyme in lipogenesis.

METHODS

Analysis was performed in a population-based, longitudinal cohort study of men (n = 2009). A product-to-precursor index (palmitoleic acid/palmitic acid) was used to estimate SCD activity in fasting serum analyzed in samples obtained at enrollment at age 50 years. Fractures were documented in 422 men during 35 years of follow-up. Cox regression analysis was used to determine the risk of fracture according to SCD activity index.

RESULTS

The risk of fracture was highest among men with the highest levels of SCD activity index. Multivariable analysis of the risk of fracture in the highest quintile as compared to the lowest one showed that the rate ratio was 1.71 (95% CI 1.26-2.33) for any fracture, with an estimated population attributable risk of 15%. The risk was further increased within the highest quintile.

CONCLUSIONS

Our results indicate that elevated levels of endogenous lipogenesis increase the risk of fracture and suggest a role for saturated fat in the pathogenesis of osteoporosis.

Fatty acid desaturases in human adipose tissue: relationships between gene expression, desaturation indexes and insulin resistance

AIMS/HYPOTHESIS

Fatty acid desaturases introduce double bonds into growing fatty acid chains. The key desaturases in humans are Delta5-desaturase (D5D), Delta6-desaturase (D6D) and stearoyl-CoA desaturase (SCD). Animal and human data implicate hepatic desaturase activities in insulin resistance, obesity and dyslipidaemia. However, the role of desaturase activity in adipose tissue is uncertain. We therefore evaluated relationships between adipose mRNA expression, estimated desaturase activities (fatty acid ratios) in adipose tissue and insulin resistance.

METHODS

Subcutaneous adipose tissue mRNA expression of D5D (also known as FADS1), D6D (also known as FADS2) and SCD was determined in 75 individuals representative of the study population of 294 healthy 63-year-old men. Desaturation indexes (product/substrate fatty acid ratios) were generated from adipose tissue fatty acid composition in all individuals. Insulin resistance was defined as the upper quartile of the updated homeostasis model assessment (HOMA-2) index.

RESULTS

The relevant desaturation indexes (16:1/16:0, 18:1/18:0, 20:4/20:3 and 18:3/18:2) reflected expression of SCD, but not of D5D or D6D in adipose tissue. Insulin-resistant individuals had a higher adipose tissue 18:1/18:0, but not 16:1/16:0 ratio than insulin-sensitive individuals. Individuals with a high adipose tissue 18:1/18:0 ratio were 4.4-fold (95% CI 1.8-11.8) more likely to be insulin resistant [threefold (95% CI 1.1-8.6) after adjustment for waist circumference and plasma triacylglycerol]. In a multiple regression model predicting HOMA-2, the independent effect of the 18:1/18:0 ratio was borderline (p=0.086).

CONCLUSIONS/INTERPRETATION

Adipose tissue desaturation indexes of SCD reflect the expression of the gene encoding the enzyme in this tissue. Elevated SCD activity within adipose tissue is closely coupled to the development of insulin resistance.

Both cyclooxygenase- and cytokine-mediated inflammation are associated with carotid intima–media thickness

BACKGROUND

Common carotid artery intima-media thickness (CCA-IMT) is a valid index of atherosclerosis, which is viewed as an inflammatory disease. It is unknown if various modes of inflammation (cyclooxygenase [COX]-mediated, cytokine-mediated), oxidative stress and anti-oxidants are independently related to CCA-IMT.

METHODS AND RESULTS

We investigated cross-sectional relations between CCA-IMT measured by B-mode ultrasound and COX-mediated inflammation (as measured by 15-keto-dihydro-prostaglandin F(2alpha) [PGF(2alpha)], cytokine-mediated inflammation (interleukin-6 [IL-6], high sensitivity C-reactive protein [hsCRP] and serum amyloid A protein [SAA]), oxidative stress (8-iso-PGF(2alpha), an F(2)-isoprostane; a non-enzymatic, free radical-induced product of arachidonic acid), and tocopherols (anti-oxidants) in a small subset of a population-based sample of elderly men (n=234) stating no use of anti-inflammatory medications. In a backward-stepwise regression analysis of correlates of CCA-IMT (with PGF(2alpha), hsCRP, IL-6, SAA, F(2)-isoprostanes, tocopherols, diabetes, body mass index (BMI), beta-blocker, statin treatment, smoking, hypertension and cholesterol), PGF(2alpha), CRP, beta-blocker treatment, diabetes and BMI were independently associated with CCA-IMT. There were no associations between F(2)-isoprostanes or tocopherols and CCA-IMT in this study.

CONCLUSION

This study suggests both COX- and cytokine-mediated inflammation to be independently associated with increased CCA-IMT, implying that there might be more than one mode of inflammation involved in atherogenesis.

Fatty acid handling protein expression in adipose tissue, fatty acid composition of adipose tissue and serum, and markers of insulin resistance

OBJECTIVE

Proteins involved in cellular fatty acid (FA) uptake and metabolism may be of relevance in the context of disturbed FA metabolism associated with insulin resistance. Therefore this study investigated relationships between FA handling protein mRNA expression in adipose tissue, FA composition of adipose tissue and serum, and markers of insulin resistance.

SUBJECTS

75 subjects with a range of insulin sensitivities recruited from a cohort of 294 healthy 63-year-old Swedish men.

MEASUREMENTS

Anthropometric and biochemical variables (e.g. waist-hip-ratio (WHR) and homeostasis model assessment (HOMA) index of insulin sensitivity), FA composition of the subcutaneous (s.c.) gluteal adipose tissue, serum nonesterified FA (NEFA) and serum phospholipid compartments (by gas-liquid chromatography; n = 294), and mRNA levels of FA handling proteins (adipocyte and keratinocyte lipid binding proteins, fatty acid transport protein (FATP) -1 and -4, CD36/fatty acid translocase, plasma membrane fatty acid binding protein, and acyl-CoA synthase-1 (ACS1)) in s.c. gluteal adipose tissue (by quantitative real-time polymerase chain reaction; n = 75).

RESULTS

ACS1 expression was negatively correlated with measures of insulin resistance and central obesity (ACS1 versus HOMA: r = -0.28, P<0.05; ACS1 versus WHR: r = -0.23, P<0.05), with an opposite trend for FATP4. Further analysis of ACS1 expression levels revealed correlations with adipose tissue 16:0 (r = -0.27, P<0.05) and NEFA 16:1 (r = 0.29, P<0.05), FA composition variables which in turn correlated with HOMA index (r = 0.39, P<0.001 and r = -0.23, P<0.05, respectively, n = 75). Moreover, NEFA 16:1 predicted ACS1 expression independently of HOMA, WHR and adipose tissue 16:0 in multiple regression analysis (standardized coefficient = 0.27, P<0.05).

CONCLUSION

Significant associations were found between measures of insulin sensitivity, adipose tissue FA handling protein expression, and specific FA composition variables. Although causal relationships could not be identified these findings suggest a role of FA handling proteins in relation to insulin sensitivity, via their involvement in FA trafficking and metabolism. In particular they indicate links between ACS1 activity, the distribution of 16:0 and 16:1, and insulin sensitivity, which may be of physiological relevance.

Glucose and insulin responses in healthy women after intake of composite meals containing cod-, milk-, and soy protein

OBJECTIVE

To evaluate the metabolic effect of three different kinds of dietary proteins as part of composite meals with similar macronutrient composition in healthy subjects.

DESIGN

A randomised meal study.

SETTING

Metabolic ward.

SUBJECTS AND METHODS

In total, 17 healthy women, 30-65 years old, consumed three meals in randomised order. The meals consisted of foodstuffs with similar nutrient composition but different types of protein (cod, cottage cheese, or soy protein isolate). The distribution of energy from protein, fat and carbohydrates was 33, 26, and 41 energy percent, respectively. Total amount of energy was 2300 kJ. Blood samples were drawn for assay of B-glucose, S-insulin, S-free fatty acids, S-triglycerides, and C-peptide in the fasting state and at seven times (20, 40, 60, 90, 120, 180, and 240 min) after starting to eat the test meal.

RESULTS

The blood glucose response after the cod protein meal differed from that of the soy protein meal, with a larger area under the curve (AUC) calculated up to 120 min. The serum insulin response after the milk protein meal differed from that of the cod protein meal with a larger AUC calculated up to 240 min. The insulin/C-peptide and the insulin/glucose ratios differed between the meals; the insulin/C-peptide ratio was higher after the milk protein meal compared to the cod, and soy protein meal at 120 min. The insulin/glucose ratio was lower after the cod protein meal compared to the milk, and soy protein meals at 120 min. The results showed that the metabolic responses differed after meals with similar macronutrient composition containing cod-, milk-, or soy protein.

Fatty acid composition of serum lipids predicts the development of the metabolic syndrome in men

AIMS/HYPOTHESIS

Types of dietary fat have been related to components of the metabolic syndrome. Serum fatty acid composition mainly reflects dietary fat intake, but also endogenous fatty acid synthesis catalysed by Delta-desaturases. It is not known whether alterations of fatty acid composition or desaturase activities predict metabolic syndrome.

MATERIALS AND METHODS

We prospectively evaluated fatty acid composition in serum cholesteryl esters and estimated desaturase activities in 1,558 50-year-old men taking part in a population-based cohort study. The follow-up time was 20 years. Stearoyl-CoA desaturase (SCD-1), Delta6 (D6D) and Delta5 (D5D) desaturases were estimated as precursor to fatty acid ratios.

RESULTS

High activity of estimated SCD-1 (odds ratio=1.29, p<0.05) and D6D (odds ratio=1.35, p<0.05), as well as low estimated D5D activity (odds ratio=0.71, p<0.001) predicted the development of metabolic syndrome (as defined by the National Cholesterol Education Program). The predictive value of D5D activity was independent of lifestyle factors (smoking, BMI and physical activity), whereas the risk associated with higher SCD-1 and D6D activities was mainly explained by obesity. Among those developing metabolic syndrome (119 out of 706) during follow-up, the proportions of fatty acids 14:0, 16:0, 16:1 (n-7), 18:1 (n-9), 18:3 (n-6) and 20:3 (n-6) were increased at baseline, while 18:2 (n-6) was decreased (p<0.05 for all).

CONCLUSIONS/INTERPRETATION

Serum fatty acid composition predicts the long-term development of the metabolic syndrome, and D5D activity may be particularly important in this process. Our results suggest a role of dietary fat quality in the development of metabolic syndrome, but the possibility that altered fatty acid composition, partly secondary to genetic or hormonal factors, should also be considered.

Active smoking and a history of smoking are associated with enhanced prostaglandin F(2alpha), interleukin-6 and F2-isoprostane formation in elderly men

The underlying mechanisms by which smoking induces cardiovascular diseases are largely unknown. The effect of smoking status on the cyclooxygenase (COX)-mediated inflammatory indicator prostaglandin F(2alpha) (PGF(2alpha)) has never been studied. Associations of cytokines and antioxidants and smoking status, have shown conflicting results. Urinary 15-keto-dihydro-PGF(2alpha) (a major metabolite of PGF(2alpha)), serum interleukin-6 (IL-6) and high sensitivity C-reactive protein (hsCRP), serum amyloid protein A (SAA), urinary 8-iso-PGF(2alpha) (an F(2)-isoprostane, indicator of oxidative stress), and serum alpha-tocopherol were quantified in a population-based sample (n = 642) of 77-year old men without diabetes. Fifty-five men were current smokers and 391 former smokers. Inflammatory indicators were increased in current smokers (15-keto-dihydro-PGF(2alpha), P < 0.001; IL-6, P = 0.01) than non-smokers. 8-iso-PGF(2alpha) was increased (P < 0.01) and alpha-tocopherol reduced (P < 0.001) in current smokers. Further, former smokers had increased formation of 15-keto-dihydro-PGF(2alpha), IL-6 and 8-iso-PGF(2alpha) compared non-smokers. This is the first study to show that smokers have increased PGF(2alpha) formation, thus enhanced COX-mediated inflammation, in addition to elevated levels of cytokines and isoprostanes. Subclinical COX- and cytokine-mediated inflammation and oxidative stress are ongoing processes not only in active smokers but also in former smokers which may contribute to the accelerated atherosclerosis associated with smoking.

Cyclooxygenase-mediated prostaglandin F2alpha is decreased in an elderly population treated with low-dose aspirin

Low-dose aspirin (acetylsalicylic acid) is used as prophylaxis against cardiovascular diseases. The effect of aspirin on inflammation and oxidative stress, processes known to be involved in cardiovascular diseases, are not fully known. The cyclooxygenase(COX)-mediated inflammatory indicator prostaglandin F2alpha (PGF2alpha) (15-keto-dihydro-PGF2alpha), cytokine-mediated inflammatory indicators (interleukin-6, high-sensitivity C-reactive protein, serum amyloid A protein), and oxidative stress indicators (8-iso-PGF2alpha, tocopherols) were quantified in men with daily 75 mg of aspirin (n=175) and control men (n=464), all of age 77, in a cross-sectional study. Men treated with aspirin had decreased levels of urinary 15-keto-dihydro-PGF2alpha than controls (P<0.01), independent of possible cardiovascular risk factors. Aspirin-treated men had increased levels of alpha-tocopherol than controls (P<0.05). This is the first study to indicate that low-dose aspirin treatment is associated with decreased levels of PGF2alpha. This observation suggests a possible COX-mediated anti-inflammatory effect of low-dose aspirin, which should be further confirmed by intervention studies.

The relation between alcohol intake and physical activity and the fatty acids 14 : 0, 15 : 0 and 17 : 0 in serum phospholipids and adipose tissue used as markers for dairy fat intake

The relative contents of the fatty acids 14 : 0, 15 : 0 and 17 : 0 in serum and adipose tissue may be used as biological markers of dairy fat intake. However, the determinants of these fatty acids are not fully understood. This study investigates the relationship between these fatty acids and the intake of macronutrients and physical activity in a cross-sectional study of 301 healthy men aged 61-64 years. Dietary intake was assessed using a pre-coded 7 d food record, and physical activity during the previous year was recorded in an interview. Under-reporters of energy intake were identified by the Goldberg cut-off. Fatty acid composition was determined in serum phospholipids (PL) and subcutaneous adipose tissue (AT) from the upper buttock. The relative content of each of 14 : 0, 15 : 0 and 17 : 0 in PL and AT was positively associated with the intake of dairy fat. In addition, all three fatty acids were inversely correlated with alcohol intake, R ranging from -0.28 to -0.53 (P<0.001). The results were not markedly affected when under-reporters (n 88) were excluded from the analyses. In both PL and AT, the relative content of the fatty acids was approximately 5% higher in a group of high physical activity compared with a group of low physical activity, although significant trends were only seen for 14 : 0 in PL and 17 : 0 in AT. The findings suggest that adjustments should be made for alcohol intake when the fatty acids 14 : 0, 15 : 0 and 17 : 0 are applied as markers for dairy fat intake.

Oxidative Stress and Changes in α- and γ-Tocopherol Levels during Coronary Artery Bypass Grafting

We studied whether cardiopulmonary bypass (CPB) has any immediate impact on the initiation of antioxidative defenses in the body by measuring F(2)-isoprostanes and alpha- and gamma-tocopherol, respectively. 8-iso-PGF(2alpha) levels increased significantly within 3 minutes and until the end of CPB. alpha-Tocopherol levels increased gradually at 20 min during CPB and continued until 6 hours after CPB. gamma-Tocopherol levels followed a similar fashion at the end of CPB. 8-iso-PGF(2alpha) and tocopherol levels kept at basal level 12 and 24 hours post CPB. These findings suggest that an increased free radical-induced oxidative stress together with a gradual appearance of antioxidative defense system during and after CPB.

Associations between the intake of dairy fat and calcium and abdominal obesity

OBJECTIVE

This study evaluates the association between abdominal obesity and the intake of dairy fat and calcium using information from dietary data and the relative content of the fatty acids 14:0, 15:0, and 17 : 0 in serum phospholipids (PL) and adipose tissue (AT), which are suggested biological markers for dairy fat intake. This study also explores how the associations were affected when under-reporters (URs) were separated from the analyses.

DESIGN

Cross-sectional study.

SUBJECTS

In all, 301 healthy 63-y-old men with different degrees of fasting-insulin concentrations.

METHODS

Sagittal abdominal obesity (SAD), dietary intake assessed by a 7-day food registration, and the fatty acid composition in serum PL and AT were measured. URs (n=88) and non-under-reporters (non-URs, n=213) were identified by Goldberg's equation, which compares energy intake with energy expenditure, both expressed as multiples of the basal metabolic rate.

RESULTS

The intake of dairy fat, expressed as g/100 g fat, was inversely correlated with SAD; however, this association was only observed in the URs (r=-0.36, P=0.001) and not in the non-URs (r=-0.04, P=0.59). The intake of calcium was inversely correlated with SAD in both groups, although the association was weaker in the non-URs. The intake of dairy fat was related to the relative content of the fatty acids 14:0, 15:0, and 17 : 0 in serum PL and AT (r ranging between 0.32 and 0.55). When these fatty acids were correlated to SAD, inverse associations were seen except for 14:0 in PL (r ranging between -0.17 and -0.29.

CONCLUSION

If there is a true inverse association between the intake of dairy fat and SAD, it remains to explain why this association was not seen in the non-URs. The data gave some indications of an inverse association between SAD and the intake of calcium. The diverse findings observed when the URs and non-URs were separated highlight the question of how to use and interpret dietary data in URs when diet-disease relationships are investigated.

Supplementation with trans10cis12-conjugated linoleic acid induces hyperproinsulinaemia in obese men: close association with impaired insulin sensitivity

AIMS/HYPOTHESIS

Hyperproinsulinaemia reflects both beta cell dysfunction and insulin resistance in cross-sectional studies, but it is not known whether changes in proinsulin concentrations are related to insulin resistance over time. As trans10cis12 (t10c12)-conjugated linoleic acid (CLA) supplementation induces insulin resistance in obese men, we used this fatty acid to investigate the effects on plasma proinsulin, insulin, C-peptide and adiponectin concentrations, including their associations with change in insulin sensitivity.

METHODS

We randomised (double-blind) 57 non-diabetic abdominally obese men to receive either 3.4 g t10c12CLA, CLA-isomer mixture or control oil for 12 weeks. Insulin sensitivity (hyperinsulinaemic-euglycaemic clamp), intact proinsulin, insulin, the proinsulin : insulin ratio, C-peptide, glucose and adiponectin were assessed before and after supplementation.

RESULTS

Supplementation with t10c12CLA increased proinsulin (p<0.01), the proinsulin : insulin ratio (p<0.05) and C-peptide concentrations (p<0.001) in comparison with control subjects. Adiponectin, however, did not change significantly. The change in proinsulin, but not the proinsulin : insulin ratio, was related to impaired insulin sensitivity (r= -0.58, p<0.0001), independently of changes in insulin, C-peptide, glucose, adiponectin and BMI. Conversely, the correlation between insulin sensitivity and specific insulin (r=-0.46, p<0.001) did not remain significant after adjustment for proinsulin. Induced hyperproinsulinaemia was also correlated to adiponectin concentrations ( r= -0.34, p<0.01).

CONCLUSIONS/INTERPRETATION

In obese men, t10c12CLA induces hyperproinsulinaemia that is related to impaired insulin sensitivity, independently of changes in insulin concentrations. These results are of clinical interest, as hyperproinsulinaemia predicts diabetes and cardiovascular disease. The use of weight-loss supplements containing this fatty acid is worrying.

No relations between breast cancer risk and fatty acids of erythrocyte membranes in postmenopausal women of the Malmö Diet Cancer cohort (Sweden)

OBJECTIVE

To examine the fatty acid composition of erythrocyte membranes, in relation to obesity indexes and breast cancer risk.

DESIGN

A nested case-control study.

SETTING

The Malmö Diet Cancer cohort, Sweden.

SUBJECTS

Among women 50 y or older at baseline (n=12 803), incident breast cancer cases (n=237) were matched to controls (n=673) on age and screening date.

METHODS

A diet history method, a structured questionnaire, anthropometrics and blood samples provided data. Analysis included partial correlation coefficients between dietary fatty acids (DFA) and fatty acids of erythrocyte membranes (EFA), and Spearman's rank order correlations between EFA and four obesity indexes. Conditional logistic regression examined breast cancer risks related to EFA.

RESULTS

DFA and EFA from fish and milk, and DFA and EFA linoleic acid, show significant positive associations. Relations are negative between indexes of obesity and "milk" EFA, but positive between indexes of obesity and indexes of delta9- and delta6-desaturase enzyme activity. No significant relations were observed between EFA and breast cancer risk.

CONCLUSIONS

Similar to other studies, dietary fish and milk fatty acids, and linoleic acid, are related to the corresponding EFA. Breast cancer risk was not significantly related to EFA in this study. However, the findings suggest positive relations between body mass index, body fat per cent and indexes of desaturase activity, and negative relations between central obesity and milk EFA.

SPONSORSHIP

The Swedish Cancer Society, the Swedish Medical Research Council, the European Commission, the Swedish Dairy Association and the City of Malmö.

Determinants of serum triglycerides and high-density lipoprotein cholesterol in traditional Trobriand Islanders: the Kitava Study

OBJECTIVES

To analyse variables explaining the variation between serum triglycerides (TGs) and high density lipoprotein cholesterol (HDL-C) in a non-western population characterized by unfavourable TG and HDL-C levels despite marked leanness, low blood pressure and low fasting serum insulin. The study subjects included yraditional Pacific Islanders from Kitava, Trobriand Islands, Papua New Guinea and a population in Sweden.

METHODS

The study was designed as a cross-sectional survey. Fasting serum lipoproteins and apolipoproteins, insulin, blood pressure and anthropometric measurements were analysed in 122 male and 47 female Kitavans aged 20-86 years and in a control population of 729 healthy men and women aged 20-66 from Uppsala. Main outcome measures were determinants of TG and HDL-C using a simple and multiple linear regression analysis.

RESULTS

A negative association was found between TGs and HDL-C in Kitava (r = -0.38. p < 0.0001) and Sweden (r = -0.46, p < 0.0001), while TGs were positively associated with non-HDL-C and ApoB in both groups. In contrast to what was found in the Swedish subjects, TG and HDL-C levels were not associated with body mass index, waist circumference, glucose, insulin or systolic blood pressure in the Kitavans.

CONCLUSION

Despite an apparent absence of cardiovascular disease and the metabolic syndrome in the Kitavans, the relationship between TGs and HDL-C was similar to that observed in Caucasians, while neither of the variables was associated with markers of insulin sensitivity in the Kitavans. Whether the findings can be explained by normal physiology or partially reflect the high intake of carbohydrates and saturated fat in Kitava is uncertain.

A programme of behaviour modification and nutrition counselling in the treatment of obesity: a randomised 2-y clinical trial

OBJECTIVE

To compare two group treatment programmes for obese outpatients. Both programmes included behaviour modification, nutrition counselling, very-low-calorie diet (VLCD) and a continuous measuring of metabolic and anthropometrical status, but they differed regarding the treatment intensiveness. The main aim was to study whether intensive treatment gives a larger weight reduction compared with less intensive treatment and what level of input from health care personnel is needed to reach adequate treatment results.

DESIGN

A 2-y randomised clinical trial.

SUBJECTS

A total of 43 obese subjects aged 24-60 y, BMI 35 kg/m(2) (29-48).

INTERVENTION

Two programmes were used. Both were based on group therapy and were supervised by a dietitian and a psychologist. Group 1 received a continuous intensive treatment with planned group meetings every fortnight during the first year and six group meetings the second year. Group 2 had planned group meetings every third month. Anthropometrical and metabolic data were measured every third month in both groups. The VLCD periods were the same.

RESULTS

There was no evidence that a more intensive treatment promotes a larger weight reduction. Weight reduction after 1 y: group 1, -7.6 (+/-0.97) kg, BMI -2.6 (+/-0.3) kg/m(2); group 2, -6.4 (+/-1.16) kg, BMI -2.2 (+/-0.4) kg/m(2). Weight reduction after 2 y: group 1, -6.8 (+/-1.4) kg, BMI -2.4 (+/-0.3) kg/m(2); group 2, -8.6 (+/-1.6) kg, BMI -3.0 (+/-0.3) kg/m(2). The dropout rate was 26%.

CONCLUSION

There were no significant differences in weight reduction, compliance or dropout rate between the groups and there was no evidence that a more intensive treatment promotes a larger weight reduction. This observation is of value when setting up treatment programmes. To measure the metabolic and anthropometrical status during the treatment and to give continuous feedback to the subjects seem to be important factors for compliance. Both treatment programmes gave highly significant weight reductions in the range of 5-10%, which has been referred to as a realistic goal for the treatment of obese patients.

Difference in effect of myristic and stearic acid on plasma HDL cholesterol within 24 h in young men

BACKGROUND

There is increasing evidence that postprandial triacylglycerol (TAG)-rich lipoproteins (TRL) may be related to atherogenic risk. Little is known about the acute effect of individual dietary saturated fatty acids on plasma lipids and lipoproteins.

OBJECTIVE

To investigate the effect of two prevalent dietary saturated fatty acids, stearic and myristic acid on postprandial and 24 h fasting plasma lipoprotein TAG and cholesterol concentrations.

DESIGN

Ten young healthy men were served two meals (1.2 g fat/kg body weight) containing fat enriched in either stearic acid (S) (shea butter) or myristic acid (M) (produced by inter-esterification) in a randomised, cross-over study. The meals were given in the morning after 12 h of fasting and again after 8 h (in the afternoon). The S and M containing meals were given at different days separated by a washout period. Blood samples were taken before the meal and 2,4,6,8, and 24 h after the first meal.

RESULTS

The M meal resulted in a higher postprandial HDL TAG response than S (P=0.03 I), (diet x time interaction), while no differences were observed in other lipid fractions. Twenty-four hours after the M meal fasting, HDL cholesterol was higher (P=0.05) and HDL TAG lower (P<0.001) than at baseline.

CONCLUSIONS

Intake of individual dietary SFA may affect fasting HDL cholesterol within 24 h. Thus after this short period HDL cholesterol concentration was higher after myristic acid than stearic acid. Myristic acid resulted in a higher increase in postprandial HDL TAG than stearic acid.

Endothelial vasodilatory function is related to the proportions of saturated fatty acids and alpha-linolenic acid in young men, but not in women

BACKGROUND

Fatty acid composition of serum lipids is associated with cardiovascular disease. As attenuated endothelium-dependent vasodilation (EDV) is an early event in atherosclerosis, we investigated the relationships between endothelial vasodilatory function and the proportion of serum fatty acids, reflecting dietary fat quality, in 74 healthy men and women, aged 20-30 years.

DESIGN

Endothelium-dependent vasodilation and endothelium-independent vasodilation (EIDV) was studied in the forearm during local administration of methacholine (2 and 4 micro g min-1) and nitroprusside (5 and 10 micro g min-1). Forearm blood flow was determined with venous occlusion plethysmography. An endothelial function index was calculated as the EDV/EIDV ratio.

RESULTS

The endothelial function index was inversely related to the total proportion of saturated fatty acids (r = -0.41, P < 0.05), in particular lauric and myristic acid (r = -0.37 and r = -0.36, respectively, P < 0.05 for both), and was positively related to the proportion of alpha-linolenic acid (r = 0.45, P < 0.01) in men only. Total serum nonesterified fatty acid (NEFA) concentration was not significantly related to endothelial vasodilatory function. By multiple stepwise regression analysis, including age, blood pressure, body mass index, and serum cholesterol, triglyceride and NEFA as confounders, myristic acid and alpha-linolenic acid were independent predictors of the endothelial function index in men only (r = -0.39 and r = 0.47, respectively, P < 0.01 for both).

CONCLUSIONS

We conclude that serum fatty acid composition predicts endothelial vasodilatory dysfunction independently of serum NEFA and cholesterol levels in young, healthy men in their third decade of life, whereas fatty acid composition seems to be less important in women at this age. As a result of the large number of analyses performed, these findings need to be verified by other studies.

Lipids and antioxidative effects of estradiol and sequential norethisterone acetate treatment in a 3-month randomized controlled trial

OBJECTIVE

To determine the influence of hormone replacement therapy on serum lipids and antioxidative factors associated with the risk of coronary heart disease.

METHODS

The effect of a sequential estradiol-norethisterone acetate regimen or placebo on lipid metabolism, antioxidative variables and fatty acid composition in serum was measured during the peak-estrogen phase in a randomized, double-blind, placebo-controlled study of 42 healthy postmenopausal women for 3 months.

RESULTS

Active treatment significantly reduced lipoprotein(a) by 15% (p = 0.005, compared with placebo), low-density lipoprotein (LDL) cholesterol by 10% (p = 0.005) and the LDL cholesterol/high-density lipoprotein (HDL) cholesterol ratio by 11% (p = 0.016). Serum triglycerides increased by 21% (p = 0.045). No effect was observed on HDL cholesterol, on apolipoproteins apo A(1) or apo B, or on non-esterified fatty acids in serum. No treatment effect was seen in the proportions of monounsaturated and polyunsaturated fatty acids. The concentration of malondialdehyde in serum did not change with the estrogen-progestin treatment.

CONCLUSIONS

This sequential estrogen-progestin therapy has a beneficial effect on apolipoprotein(a) and LDL cholesterol, but no effect on non-esterified fatty acids or the level of lipid peroxidation products in serum.

Desaturation and elongation of Fatty acids and insulin action

Insulin resistance is characterized by specific changes of the composition of fatty acids in the serum lipids and in the skeletal muscle membranes. Impaired insulin sensitivity is associated with high proportions of palmitic (16:0) acid and low levels of linoleic (18:2 n-6) acid in serum. In addition, there are apparent changes of the fatty acid desaturase activities, suggesting an increased activity of the Delta9 and Delta6 desaturases and a decreased activity of the Delta5 desaturase. The activity of the fatty acid desaturases is regulated by long-chain polyunsaturated fatty acids and insulin and is probably also dependent on the degree of physical activity. A high ratio between arachidonic (20:4 n-6) and dihomo-gamma linolenic (20:3 n-6) acid, as a measure of Delta5 desaturase activity, in the skeletal muscle phospholipids has been related to good insulin sensitivity. Available knowledge seems to indicate that the degree of saturation of the body lipids, and especially the proportion of palmitic acid in the lipid membranes, may be critical for insulin sensitivity. The strong relationships between the Delta5 desaturase activity, a high content of long-chain polyunsaturated fatty acids in the skeletal muscle, and insulin sensitivity may be due to parallel effects of diet and/or physical activity on the fatty acid composition and on insulin sensitivity.

Oxidative stress and antioxidant status in type 1 diabetes mellitus

OBJECTIVES

To test the hypothesis that type 1 diabetes is associated with increased oxidative stress and/or antioxidant status by investigating concentrations of 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha) in urine and plasma and malondialdehyde (MDA) in plasma as indicators of lipid peroxidation in vivo, and antioxidant status in diabetic subjects compared with healthy control subjects.

DESIGN AND SUBJECTS

Thirty-eight subjects with type 1 diabetes mellitus and 41 healthy age- and sex-matched control subjects were included in the study. Blood and urine samples were obtained and analysed for 8-iso-PGF2alpha with a newly developed radioimmunoassay, as well as for MDA, total antioxidant capacity (TAOC) and serum tocopherol levels.

RESULTS

None of the variables of lipid peroxidation showed any significant difference between the two groups. Similarly, there were no significant correlations between the levels of 8-iso-PGF2alpha or MDA, and degree of glycemic control (HbA1c). Total antioxidant capacity in plasma was 16% lower amongst the subjects with type 1 diabetes than in the control group (P < 0.0005). Lipid corrected levels of alpha-tocopherol in serum were significantly increased in type 1 diabetic subjects (P < 0.05), as were gamma-tocopherol levels (P < 0.005).

CONCLUSIONS

In spite of lower total antioxidant defence, our results do not support the oxidative stress hypothesis for type 1 diabetes mellitus. The higher tocopherol levels suggest that no vitamin E supplementation is necessary for subjects with type 1 diabetes mellitus.

Plasminogen activator inhibitor-1 and relations to fatty acid composition in the diet and in serum cholesterol esters

High plasminogen activator inhibitor (PAI)-1 levels and poor dietary fat quality are potential risk factors for cardiovascular disease. The aim was to investigate the cross-sectional associations between PAI-1 activity and dietary nutrient intake, focusing on fat quality, in a population-based study of 871 men aged 70 years. The relationship between PAI-1 and the fatty acid composition in serum cholesterol esters (n=381 men) was also studied. The estimated total fat intake was positively associated with PAI-1 activity. The intake of both monounsaturated and polyunsaturated fatty acids was positively associated with PAI-1 activity, whereas the intake of saturated fatty acids was not. In serum cholesterol esters, higher proportions of palmitoleic and dihomo-gamma-linolenic acid, a lower proportion of linoleic acid, and reduced estimated Delta5-desaturase activity were associated with higher PAI-1 levels. These associations were confounded by factors representing the insulin resistance syndrome. PAI-1 activity was positively associated with gamma-linolenic and arachidonic acid, independent of potential confounders. In conclusion, this study demonstrates that dietary intake of unsaturated fatty acids is positively associated with PAI-1 activity, whereas intake of saturated fatty acids is not. The associations present between PAI-1 activity and the fatty acid proportions in serum cholesterol esters are partly influenced by metabolic syndrome-related factors.

A diet containing rapeseed oil-based fats does not increase lipid peroxidation in humans when compared to a diet rich in saturated fatty acids

OBJECTIVE

To compare the effects of a rapeseed oil-based diet containing an increased proportion of easily oxidised polyunsaturated fatty acids such as alpha-linolenic acid with a diet rich in saturated fatty acids on the degree of lipid peroxidation in the human body.

DESIGN

A randomised cross-over study.

SUBJECTS AND INTERVENTIONS

Nineteen healthy moderately hyperlipidemic subjects (six women and 13 men, age 50+/-8 y and body mass index (BMI) 24.5+/-2.6 kg/m(2)) were given a rapeseed oil-based diet (RO) and a control diet (SAT) rich in saturated fatty acids during two consecutive 4 week periods separated by a 4 week wash-out period. Biomarkers of lipid peroxidation and antioxidants were analysed in plasma and urine.

RESULTS

No significant differences in plasma or urinary levels of free 8-iso-prostaglandin F(2alpha), plasma total 8-iso-prostaglandin F(2alpha) plasma hydroperoxides or plasma malondialdehyde were observed between the RO and SAT diets (P=0.14-0.95). A higher concentration of serum gamma-tocopherol was detected after the RO diet compared to the SAT diet (P<0.001), whereas the serum alpha-tocopherol concentration and plasma antioxidative capacity did not differ between the two test diets. The total cholesterol, LDL cholesterol and LDL/HDL ratio were lower after the RO diet compared to the SAT diet (P<0.001), while HDL cholesterol and total triglyceride levels were similar after the two diets.

CONCLUSION

These results suggest that a rapeseed oil-based diet rich in alpha-linolenic acid does not seem to increase the degree of lipid peroxidation in plasma and urine compared to a diet rich in saturated fats. This is possibly due to a sufficient content of antioxidants in the rapeseed oil diet to increase circulating concentrations of antioxidants that may protect unsaturated fatty acids from oxidation.

SPONSORSHIP

Swedish Council for Forestry and Agricultural Research and Foundation for Geriatric Research.

Education, lifestyle factors and mortality from cardiovascular disease and cancer. A 25-year follow-up of Swedish 50-year-old men

BACKGROUND

There is a well-established inverse relation between education and mortality from cardiovascular disease and cancer. The reasons for this are still in part unclear. We aimed to investigate whether differences in traditional vascular risk factors, adult height, physical activity, and biomarkers of fatty acid and antioxidant intake, could explain this association.

METHODS

In all, 2301 50-year-old men in Uppsala, Sweden (82% of the background population) were examined with regard to educational level, blood pressure, blood glucose, body mass index, serum lipids, smoking, body height, physical activity, serum beta carotene, alpha tocopherol, selenium, and serum fatty acids in cholesterol esters. Cause-specific mortality was registered 25 years later.

RESULTS

Low education was associated with a higher rate of mortality from cardiovascular disease (crude relative risk [RR] = 1.67, 95% CI : 1.17-2.39), and from cancer (crude RR = 1.94, 95% CI : 1.21-3.10), compared to high educational attainment. Men with high education had an overall more beneficial risk factor profile concerning traditional cardiovascular risk factors, physical activity, and biomarkers of dietary intake of antioxidants and fat. After adjustment for all examined risk factors, the inverse gradient between education and cardiovascular mortality disappeared (RR in low education = 1.01. 95% CI : 0.67-1.52). Controlling for smoking, physical activity and dietary biomarkers explained less than half of the excess cancer mortality in the lower educational groups. Smoking (adjusted RR = 1.89, 95% CI : 1.37-2.61), and high proportions of palmitoleic acid in serum cholesterol esters (adjusted RR per 1 SD = 1.39, 95% CI : 1.07-1.82) predicted cancer mortality, independently of all other factors. There were no independent relations between serum antioxidants and mortality.

CONCLUSIONS

These data indicate that modifiable lifestyle factors mediate the inverse gradient between education and death from cerebro- and cardiovascular disease. Smoking, physical activity and dietary factors explained half of the excess cancer mortality in lower educated groups. Further studies are needed to explore the proposed association between palmitoleic acid, a marker of high intake of animal and dairy fat, and cancer.

Several factors associated with the insulin resistance syndrome are predictors of left ventricular systolic dysfunction in a male population after 20 years of follow-up

BACKGROUND

The epidemiologic data on heart failure are scarce. This study aimed at identifying predictors of left ventricular systolic dysfunction in a cohort of middle-aged men with a 20-year follow-up.

METHODS

A population-based cohort of 431 50-year-old men was examined with blood pressure and anthropometric measurements together with lipid, glucose, and insulin determinations. A reinvestigation 20 years later also included echocardiography, ambulatory blood pressure monitoring, hyperinsulinemic euglycemic clamp, and oral glucose tolerance test. Sixteen subjects were found to have left ventricular systolic dysfunction at age 70 years, defined as an ejection fraction </=0.40. A control group of 48 subjects matched on myocardial infarction, hypertension, diabetes, and use of cardiovascular medication, but with an ejection fraction >0.40, was used in a nested case-control analysis.

RESULTS

At age 50 years, heart rate (P <.01), plasma proinsulin (P <.05), and the proportion of dihomogammalinolenic acid in serum cholesterol esters (P <.05) were increased and serum phosphate decreased (P <.01) in the subjects identified with left ventricular systolic dysfunction at age 70 years compared with controls. No major metabolic abnormalities were associated with left ventricular systolic dysfunction at age 70 years compared with controls.

CONCLUSION

Factors associated with insulin resistance precede left ventricular systolic dysfunction independently of ischemic heart disease and hypertension after 20 years of follow-up.

Markers of high fish intake are associated with decreased risk of a first myocardial infarction

High intake of fish has been associated with reduced risk of CHD. The high content of n-3 polyunsaturated fatty acids (PUFA) in fish has been suggested to be a protective factor. In addition, fish is the entirely dominating source of methylmercury for the general population, and the concentration of Hg in erythrocytes (Ery-Hg) is often used as an index of fish consumption. Our aim was to study the relationships between a first-ever myocardial infarction, Ery-Hg, activity of gluthathione peroxidase in erythrocytes (Ery-GSH-Px) and plasma concentration of the n-3 PUFA eicosapentaenoic and docosahexaenoic acids (P-PUFA). In a population-based prospective nested case-control study within Northern Sweden seventy-eight cases of a first-ever myocardial infarction were compared with 156 controls with respect to Ery-Hg, P-PUFA and Ery-GSH-Px. Both Ery-Hg and P-PUFA, but not Ery-GSH-Px, were significantly higher in subjects reporting high fish intake (at least one meal per week) than in those with lower intake. This finding suggests that Ery-Hg and P-PUFA reflect previous long-term fish intake. Low risk of myocardial infarction was associated with high Ery-Hg or high P-PUFA. In a multivariate model the risk of myocardial infarction was further reduced in subjects with both high Ery-Hg and high P-PUFA (odds ratio 0.16, 95 % CI 0.04, 0.65). In conclusion, there is a strong inverse association between the risk of a first myocardial infarction and the biomarkers of fish intake, Ery-Hg and P-PUFA, and this association is independent of traditional risk factors.