Influence of three rapeseed oil-rich diets, fortified with alpha-linolenic acid, eicosapentaenoic acid or docosahexaenoic acid on the composition and oxidizability of low-density lipoproteins: results of a controlled study in healthy volunteers.

OBJECTIVE: To compare the individual effects of dietary alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) on low-density lipoprotein (LDL) fatty acid composition, ex vivo LDL oxidizability and tocopherol requirement. DESIGN, SETTING AND SUBJECTS: A randomized strictly controlled dietary study with three dietary groups and a parallel design, consisting of two consecutive periods. Sixty-one healthy young volunteers, students at a nearby college, were included. Forty-eight subjects (13 males, 35 females) completed the study. INTERVENTIONS: Subjects received a 2-week wash-in diet rich in monounsaturated fatty acids (21% energy) followed by experimental diets enriched with about 1% of energy of ALA, EPA or DHA for 3 weeks. The omega-3 (n-3) fatty acids were provided with special rapeseed oils and margarines. The wash-in diet and the experimental diets were identical, apart from the n-3 fatty acid composition and the tocopherol content, which was adjusted to the content of dienoic acid equivalents. RESULTS: Ex vivo oxidative susceptibility of LDL was highest after the DHA diet, indicated by a decrease in lag time (-16%, P<0.001) and an increase in the maximum amount of conjugated dienes (+7%, P<0.001). The EPA diet decreased the lag time (-16%, P<0.001) and the propagation rate (-12%, P<0.01). Tocopherol concentrations in LDL decreased in the ALA group (-13.5%, P<0.05) and DHA group (-7.3%, P<0.05). Plasma contents of tocopherol equivalents significantly decreased in all three experimental groups (ALA group: -5.0%, EPA group: -5.7%, DHA group: -12.8%). The content of the three n-3 polyunsaturated fatty acid differently increased in the LDL: on the ALA diet, the ALA content increased by 89% (P<0.001), on the EPA diet the EPA content increased by 809% (P<0.001) and on the DHA diet, the DHA content increased by 200% (P<0.001). In addition, the EPA content also enhanced (without dietary intake) in the ALA group (+35%, P<0.01) and in the DHA group (+284%, P<0.001). CONCLUSIONS: Dietary intake of ALA, EPA or DHA led to a significant enrichment of the respective fatty acid in the LDL particles, with dietary EPA preferentially incorporated. In the context of a monounsaturated fatty acid-rich diet, ALA enrichment did not enhance LDL oxidizability, whereas the effects of EPA and DHA on ex vivo LDL oxidation were inconsistent, possibly in part due to further changes in LDL fatty acid composition.

Effects of dietary fatty acids on the composition and oxidizability of low-density lipoprotein.

OBJECTIVE: The objective of this study was to compare the effects of dietary monounsaturated fatty acids (MUFA), n-6 and n-3 polyunsaturated fatty acids (PUFA) on LDL composition and oxidizability. DESIGN, SETTING AND SUBJECTS: Sixty-nine healthy young volunteers, students at a nearby college, were included. Six subjects withdrew because of intercurrent illness and five withdrew because they were unable to comply with the dietary regimen. INTERVENTIONS: The participants received a 2-week wash-in diet rich in saturated fatty acids (SFA) followed by diets rich in refined olive oil, rapeseed oil or sunflower oil for 4 weeks. Intakes of vitamin E and other antioxidants did not differ significantly between the diets. RESULTS: At the end of the study, LDL oxidizability was lowest in the olive oil group (lag time: 72.6 min), intermediate in the rapeseed oil group (68.2 min) and highest in the sunflower oil group (60.4 min, P<0.05 for comparison of all three groups). Despite wide variations in SFA intake, the SFA content of LDL was not statistically different between the four diets (25.8-28.5% of LDL fatty acids). By contrast, the PUFA (43.5%-60.5% of LDL fatty acids) and MUFA content of LDL (13.7-29.1% of LDL fatty acids) showed a wider variability dependent on diet. CONCLUSIONS: Enrichment of LDL with MUFA reduces LDL susceptibility to oxidation. As seen on the rapeseed oil diet this effect is independent of a displacement of higher unsaturated fatty acids from LDL. Evidence from this diet also suggests that highly unsaturated n-3 fatty acids in moderate amounts do not increase LDL oxidizability when provided in the context of a diet rich in MUFA.

Changes in hemostasis during treatment of hypertriglyceridemia with a diet rich in monounsaturated and n-3 polyunsaturated fatty acids in comparison with a low-fat diet.

High levels of fibrinogen, factor (F) VIIc, plasminogen activator inhibitor-1 (PAI-1), and plasma viscosity are associated with an increased coronary risk. As positive correlations of these parameters with triglycerides have been shown, the increased coronary risk associated with high levels of triglycerides may be assumed to be due to alterations within the hemostatic system. To reduce the coronary risk to which hypertriglyceridemic patients are exposed, dietary treatment is recommended; the optimal composition of such a diet is, however, a matter of debate. With regard to the effects on hemostasis, we compared in a sequential approach two diets for treatment of 25 nonobese male patients (age, mean+/-S.D., 40.4+/-8.7 years) with fasting triglycerides >2.3 mmol/l. The first diet (high fat) was rich in monounsaturated fatty acids (MUFA) and marine n-3 polyunsaturated fatty acids (PUFA), whereas the second diet (low-fat) was rich in complex carbohydrates and dietary fiber. The high-fat diet induced a significant lowering of FIIc, FIXc, FXc, FVIIc, FVIIa, FXIIa, PAI-1, plasma viscosity, and platelet activity, but led to an increase in fibrinogen, whereas the low-fat diet lowered FXIIc values and induced a nonsignificant decrease in fibrinogen. Probands on this diet had a slightly higher FVIIa and platelet activity than those on the high-fat diet. However, as all changes appeared to be within the normal range of each hemostatic parameter, it remains to be clarified whether the likely beneficial effects of the high-fat diet on most hemostatic factors are outweighed by the small increase in fibrinogen levels.

Effects of diets containing olive oil, sunflower oil, or rapeseed oil on the hemostatic system.

Various studies have already shown that the fatty acid composition of dietary fat has different effects on hemostasis and platelet function. However, knowledge on this topic is incomplete. In the present study, fifty-eight healthy students received either a 4-week rapeseed oil [high content of monounsaturated fatty acids (MUFA) and high n-3/n-6 PUFA ratio], an olive oil (high content of MUFA, low n-3/n-6 PUFA ratio) or a sunflower oil (low content of MUFA, low n-3/n-6 PUFA ratio) diet. In each group, effects on hemostatic parameters were compared with a wash-in diet rich in saturated fatty acids with respect to intermediate-time effects on the hemostatic system and platelet function. With the olive oil diet, a reduction of coagulation factors VIIc, XIIc, XIIa, and Xc was found, whereas sunflower oil led to lower values of coagulation factors XIIc, XIIa, and IXc. In all study groups levels of plasmin-alpha2-antiplasmin were lower in week 4 than at baseline. Lower fibrinogen binding on platelets was found after the sunflower oil diet, whereas expression of CD62 and spontaneous platelet aggregation were slightly higher after the olive oil diet. However, given the major differences in the fatty acid compositions of the diets, the differences between the groups with respect to hemostasis tended to be small. Therefore, the clinical significance of the present findings remains to be evaluated.

Treatment of hypertriglyceridemia by two diets rich either in unsaturated fatty acids or in carbohydrates: effects on lipoprotein subclasses, lipolytic enzymes, lipid transfer proteins, insulin and leptin.

BACKGROUND: There is lack of agreement on which dietary regimen is most suitable for treatment of hypertriglyceridemia, especially if high triglyceride concentrations are not due to obesity or alcohol abuse. We compared the effects on blood lipids of a diet high in total and unsaturated fat with a low-fat diet in patients with triglyceride concentrations of > 2.3 mmol/l. METHODS: Nineteen non-obese male outpatients with triglycerides ranging from 2.30 to 9.94 mmol/l received two consecutive diets for 3 weeks each: first a modified high-fat diet (39% total fat, 8% SFA, 15% monounsaturated fatty acids, 1.6% marine n-3 polyunsaturated fatty acids), and then a low-fat diet (total fat 28%, carbohydrates 54%). RESULTS: The high-fat diet significantly decreased triglycerides (-63%), total cholesterol (-22%), VLDL cholesterol (-54%), LDL cholesterol ( 16%), total apoC-III (-27%), apoC-III in apoB containing lipoproteins (apoC-III LpB; -31%) and in HDL (apoC-III nonLpB; -29%), apoE in serum (-33%) and apoB-containing lipoproteins (nonHDL-E; -42%), LpA-I (-16%), insulin (-36%), and leptin (-26%) and significantly increased the means of HDL cholesterol (+8%), LDL size (+6%), lipoprotein lipase (LPL, +11%), hepatic lipase (+13%), and lecithin: cholesterol acyltransferase (LCAT, +2%). The subsequent low-fat diet increased triglycerides (+63%), VLDL cholesterol (+19%), apoC-III (+23%), apoC-III LpB (+44%) apoC-III nonLpB (+17%), apoE (+29%) and nonHDL-E (+43%), and decreased HDL cholesterol (-12%), LPL (-3%), and LCAT (-3%). Changes in triglycerides correlated with changes in LPL activity and insulin levels. CONCLUSIONS: In hypertriglyceridemic patients, a modified diet rich in mono- and n-3 polyunsaturated fatty acids is more effective than a carbohydrate-rich low-fat diet in correcting the atherogenic lipoprotein phenotype.

Food supply abundant increase of serum selenium concentrations in middle-aged Dresden women between 1990 and 1996. DRECAN-Team. Dresden Cardiovascular Risk and Nutrition.

Serum selenium concentration was measured in middle-aged Dresden (East Germany) women in 1990 and 1996. In 1990, the serum concentration of selenium in middle-aged women was higher than in men living under the same environmental conditions (0.98 +/- 0.32 vs 0.82 +/- 0.19 micromol/l). In 1996, the serum concentration of selenium in middle-aged women was significantly higher than in 1990 (1.19 +/- 0.34 micromol/l). This increase seems to be caused by the changed foodstuff supply after the reunification of Germany. Selenium values did not correlate with age, blood pressure or daily energy intake. Moderate smoking and menopausal status did not influence the selenium levels. In 1990, the serum concentration of selenium was the highest in those women who consumed the lowest amounts of carbohydrates or fibers, or who had the highest consumption of meat, fresh fish or potatoes.

Dietary habits in Eastern Germany: changes after reunification and their relation to CHD risk profiles (DRECAN).

As part of the DREsden CArdiovascular risk and Nutrition study, 2038 participants, selected from a cohort of 3076 workers in the Dresden area, underwent a detailed nutritional analysis of the periods before and after German reunification. Although protein, fat, carbohydrate, and total calorie intake did not change in Dresden after reunification, polyunsaturated fat replaced 17% of the saturated fatty acids, dairy product intake tripled, and fruit intake increased by 70%. Relative to a reference PROCAM 'western' cohort, the 90th percentile of triglycerides was higher in middle-aged men, and the levels of total cholesterol and HDLC were higher in all males. Serum LDLC levels in males and females were similar. Serum lipid concentrations and the prevalence of hyperlipidemia were similar to those of the PROCAM cohort, but smoking was less common. In young males and females, body mass index was higher; hypertension was more frequent. We assume that the differences in nutrition and risk profile before reunification were less substantial than commonly believed.

Electrophoretic screening for human apolipoprotein C-II variants: repeated identification of apolipoprotein C-II(K19T).

Screening for apolipoprotein (apo) C-II variants in the plasma of 400 students, 600 patients of a cardiological rehabilitation center, and 1200 patients of an outpatient lipid clinic by isoelectric focusing and subsequent anti-apo C-II immunoblotting led to the identification of four individuals whose plasma samples contained an apo C-II isoform with an abnormal isoelectric point. In all cases direct sequencing of PCR-amplified DNA assessed a heterozygous A to C transversion in codon 19 of the apo C-II gene which leads to the replacement of lysine with threonine. Two of the four index patients presented with moderate hypertriglyceridemia; one suffered from severe hyperlipidemia, with triglyceride levels ranging between 180 and 1900 mg/dl, depending on dietary changes. Sequencing of this proband's lipoprotein lipase gene showed no alteration compared to the wild-type sequence. A study in his family revealed that heterozygosity for apo C-II(K19T) is not associated with differences in mean lipid and lipoprotein concentrations. In conclusion, apo C-II(K19T) occurs in Germany at a frequency of approximately 1 in 550. Although this variant is not sufficient to cause hypertriglyceridemia, it may be possible that apo C-II(K19T) cause hypertriglyceridemia in the presence of additional as yet unidentified environmental and/or genetic factors.

Effects of two kinds of decaffeinated coffee on serum lipid profiles in healthy young adults.

OBJECTIVE: To investigate the effects of two kinds of decaffeinated coffee on serum lipid profiles in healthy young adults. DESIGN: Randomized controlled study with three study groups and a parallel design, consisting of two consecutive periods. SETTING: Outpatient clinical research center in a university clinic. SUBJECTS: 119 healthy students (60 male, 59 female) who were selected after a screening. All completed the study. Blood samples of three subjects (1 male, 2 female) were excluded from evaluation due to later diagnosed genetic anomalies of lipid metabolism. INTERVENTIONS: All subjects consumed 750-1000 ml of caffeinated filtered coffee per day for a 2 week wash-in period. During the 6 week test period one group continued drinking the caffeinated coffee, while the two other groups consumed different kinds of decaffeinated coffee. RESULTS: Consumption of both types of decaffeinated coffee did not lead to any significant changes in serum total and LDL cholesterol, triglycerides and apolipoprotein B. Furthermore, there were no significant differences in the reactions between the three groups. The diet did not change during the study. CONCLUSIONS: Switch from regular to decaffeinated coffee had no cholesterol-elevating effects, irrespective of the type of coffee.

Comparative effects of a recommended lipid-lowering diet vs a diet rich in monounsaturated fatty acids on serum lipid profiles in healthy young adults.

This crossover study investigated the effects of two fat-reduced diets, one rich in monounsaturated fatty acids (MUFAs), the other rich in polyunsaturated fatty acids (PUFAs), on serum lipid profiles in 38 healthy young adults initially on a typical western diet. After being randomly assigned to two groups, the subjects received the MUFA or PUFA diet for 3-wk and then the other diet for 3 wk. Both test diets led to significant reductions in serum cholesterol, LDL cholesterol, and HDL cholesterol (P less than 0.001). Both reduced apolipoprotein B (P less than 0.001) and apolipoprotein A-I concentrations (P less than 0.01 for the MUFA, P less than 0.001 for the PUFA diet). Apolipoprotein A-I was significantly higher on the MUFA than on the PUFA diet. The ratio of apolipoprotein A-I to B significantly increased on both diets. Thus, a low-fat, MUFA-rich diet is as effective as a low-fat, PUFA-rich diet in lowering total and LDL cholesterol, but both also lowered HDL cholesterol concentrations. The MUFA-rich diet may be more advantageous than the PUFA-rich one because it does not lower apolipoprotein A-I concentrations as much as the PUFA-rich diet.