The effect of a lignan complex isolated from flaxseed on inflammation markers in healthy postmenopausal women.

BACKGROUND AND AIM: Plant lignans are metabolised by the colonic micro-flora to the mammalian lignans enterodiol and enterolactone, which are hypothesized to be cardioprotective. The aim of this study was to investigate the effects of a plant lignan complex isolated from flaxseed, providing 500 mg/d of secoisolariciresinol diglucoside, on inflammatory markers. METHODS AND RESULTS: Healthy postmenopausal women (n=22) completed a randomised double-blind, placebo-controlled crossover study. Women consumed daily a low-fat muffin, with or without a lignan complex, for 6 weeks, separated by a 6-week washout period. A significant difference of approximately 15% (P=0.028) was observed for C-reactive protein (CRP) concentration between the lignan complex intervention period and placebo period. CRP concentrations (median; 25th, 75th percentiles) were 0.88 (0.63, 2.05) mg/L at baseline and 0.92 (0.59, 1.49) mg/L after the lignan complex intervention period compared with 0.80 (0.62, 1.62) mg/L at baseline and 1.10 (0.72, 1.62) mg/L after placebo. No significant differences in interleukin-6, tumor necrosis factor-alpha, soluble intracellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and monocyte chemoattractant protein-1 were found between the lignan complex intervention period and placebo period. CONCLUSION: Daily consumption for 6 week of a low-fat muffin enriched with a lignan complex may reduce CRP concentrations compared to a low-fat muffin with no lignans added.

Soya isoflavone-enriched cereal bars affect markers of endothelial function in postmenopausal women.

Soya isoflavones are thought to be cardioprotective due to their structural similarity to oestrogen. In order to investigate the effect of soya isoflavones on markers of endothelial function we conducted a randomised, double-blind, placebo-controlled, cross-over study with thirty healthy postmenopausal women. The women consumed cereal bars, with or without soya isoflavones (50 mg/d), for 8 weeks, separated by an 8-week washout period. Systemic arterial compliance (SAC), isobaric arterial compliance (IAC), flow-mediated endothelium-dependent vasodilation (FMD) and nitroglycerine-mediated endothelium-independent vasodilation (NMD) were measured at the beginning of the study and after each intervention period. Blood pressure (BP) and plasma concentrations of nitrite and nitrate (NOx) and endothelin-1 (ET-1) were measured at the beginning and end of each intervention period. NMD was 13.4 (SEM 2.0)% at baseline and 15.5 (SEM 1.1) % after isoflavone treatment compared with 12.4 (SEM 1.0)% after placebo treatment (P=0.03). NOx increased from 27.7 (SEM 2.7) to 31.1 (SEM 3.2) microM after isoflavones treatment compared with 25.4 (SEM 1.5) to 20.4 (SEM 1.1) microM after placebo treatment (P=0.003) and a significant increase in the NOx:ET-1 ratio (P=0.005) was observed after the isoflavone treatment compared with placebo. A significant difference in SAC after the isoflavone and placebo treatment was observed (P=0.04). No significant difference was found in FMD, IAC, BP and ET-1. In conclusion, 8 weeks' consumption of cereals bars enriched with 50 mg soya isoflavones/d increased plasma NOx concentrations and improved endothelium-independent vasodilation in healthy postmenopausal women.

Effect of dietary fatty acids on the postprandial fatty acid composition of triacylglycerol-rich lipoproteins in healthy male subjects.

OBJECTIVE: The aim of the present study was to investigate the effect of trans-18:1 isomers compared to other fatty acids, especially saturates, on the postprandial fatty acid composition of triacylglycerols (TAG) in chylomicrons and VLDL. DESIGN: A randomised crossover experiment where five interesterified test fats with equal amounts of palmitic acid (P fat), stearic acid (S fat), trans-18:1 isomers (T fat), oleic acid (O fat), or linoleic acid (L fat) were tested. SUBJECTS: A total of 16 healthy, normolipidaemic males (age 23+/-2 y) were recruited. INTERVENTIONS: The participants ingested fat-rich test meals (1 g fat per kg body weight) and the fatty acid profiles of chylomicron and VLDL TAG were followed for 8 h. RESULTS: The postprandial fatty acid composition of chylomicron TAG resembled that of the ingested fats. The fatty acids in chylomicron TAG were randomly distributed among the three positions in accordance with the distributions in test fats. Calculations of postprandial TAG concentrations from fatty acid data revealed increasing amounts up to 4 h but lower response curves (IAUC) for the two saturated fats in accordance with previous published data. The T fat gave results comparable to the O and L fats. The test fatty acids were much less reflected in VLDL TAG and there was no dietary influence on the response curves. CONCLUSIONS: The fatty acid composition in the test fats as well as the positional distributions of these were maintained in the chylomicrons. No specific clearing of chylomicron TAG was observed in relation to time.

Different effects of whole milk and a fermented milk with the same fat and lactose content on gastric emptying and postprandial lipaemia, but not on glycaemic response and appetite.

Longitudinal studies indicate that milk and fermented milk products lower basal plasma cholesterol concentrations, despite their high content of saturated fat, and therefore have favourable health effects. However, there have been few studies on the postprandial effects of milk products. The present study compared the effect of whole milk with a fermented milk, A-38, on postprandial carbohydrate and lipid metabolism, gastric emptying and appetite. Eight healthy young men participated. On the two test days, they arrived fasting for collection of baseline values before consuming the meals, which for a 75 kg subject consisted of 1.4 litre milk or fermented milk, plus 165 mg [13C]acetate (for later determination of gastric emptying by a [13C]acetate breath test). Lactose (15 g) was added to the A-38 meal to equalize the lactose content. Postprandially the A-38 meal resulted in a slower gastric emptying rate than milk (P<0.001). Furthermore, the A-38 meal resulted in a greater increase and a quicker decrease of the triacylglycerol content in all lipoprotein fractions (LDL-fraction, P<0.05; other fractions, P<0.001) and of the gastrointestinal hormones (cholecystokinin and peptide YY, P<0.05; gastric inhibitory polypeptide and glucagon-like polypeptide-1, P<0.001). There were no significant differences in appetite sensations (measured by visual analogue scale) or in the glucose and insulin response (P>0.10). The slower emptying rate of the liquid phase after the A-38 meal is probably due to the higher viscosity of A-38. The lower and more prolonged triacylglycerol response after the milk meal might be caused by coagulation of milk in the stomach.

Effects of trans- and n-3 unsaturated fatty acids on cardiovascular risk markers in healthy males. An 8 weeks dietary intervention study.

BACKGROUND: Studies of long-term intake of industrially produced trans fatty acids (TFA) and n-3 polyunsaturated fatty acids (PUFA) suggest opposite effects on cardiovascular disease risk. Common mechanisms of action are probable. OBJECTIVE: To examine the effects on cardiovascular risk markers of dietary enrichment with TFA or n-3 PUFA. DESIGN: Randomized, double-blind, parallel intervention trial. SETTING: Department of Human Nutrition, The Royal Veterinary and Agricultural University. SUBJECTS: In all, 87 healthy males included, 79 completed. INTERVENTION: Subjects were randomly assigned to 8 weeks of a daily intake of 33 g of experimental fats from either partially hydrogenated soy oil containing 20 g of TFA, 12 g of fish oil with approximately 4 g of n-3 PUFA and 21 g of control fat, or 33 g of control fat. The experimental fats were incorporated into bakery products. Plasma lipids, blood pressure, heart rate variability (HRV), arterial dilatory capacity, compliance, and distensibility were recorded before and after intervention and at follow-up 12 weeks after the intervention. RESULTS: High-density lipoprotein cholesterol (HDL-C) decreased in the TFA group and triglycerides and mean arterial blood pressure decreased in the n-3 PUFA group compared to the control group. HRV, arterial dilatory capacity, compliance, and distensibility were unchanged. CONCLUSION: The results indicate that the association between coronary heart disease risk and intake of TFA and n-3 PUFA relates only modestly to changes in traditional risk markers. SPONSORSHIP: Danish Medical Research Council (Grant no. 22-01-0390), Center of Advanced Food Research (Copenhagen, Denmark) (Grant no. KVL-R-2001-107), the Danish Heart Association (Grant no. 99-2-3-45-22748), Novozymes (Bagsvaerd, Denmark), Aarhus Olie (Aarhus, Denmark), and from private sources. The experimental fats were provided by Pronova Biocare (Aalesund, Norway) and Aarhus Olie (Aarhus, Denmark).

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.

Effect of 6 dietary fatty acids on the postprandial lipid profile, plasma fatty acids, lipoprotein lipase, and cholesterol ester transfer activities in healthy young men.

BACKGROUND: There is increasing evidence that postprandial triacylglycerol-rich lipoproteins may be related to atherogenic risk. OBJECTIVE: The objective was to investigate the effect of individual fatty acid intakes on postprandial plasma lipoprotein triacylglycerol and cholesterol concentrations, plasma fatty acids, and preheparin lipoprotein lipase and cholesterol ester transfer protein (CETP) activities. DESIGN: Six test fats high (approximately 43% by wt) in stearic acid, palmitic acid, palmitic + myristic acid, oleic acid, elaidic acid (trans 18:1), and linoleic acid were produced by interesterification. After having fasted for 12 h, 16 healthy young men were served the individual test fats incorporated into meals (1 g fat/kg body wt) in random order on different days separated by washout periods. Blood samples were drawn before and 2, 4, 6, and 8 h after the meals. RESULTS: Different responses to the test-fat meals were observed for plasma lipoprotein triacylglycerol and cholesterol concentrations, plasma fatty acid concentrations, and lipoprotein lipase and CETP activities (diet x time interaction: 0.001 < P < 0.05). Intake of the long-chain saturated fatty acids stearic and palmitic acids resulted in a relatively lower lipemic response than did intake of the unsaturated fatty acids, probably because the saturated fatty acids were absorbed less and at a lower rate; therefore, the lipemic response took longer to return to postabsorptive values. CONCLUSIONS: Fatty acid chain length and degree of saturation appear to affect the extent and duration of lipemia and affect hepatic output indirectly. These effects may not be mediated via effects on lipoprotein lipase and CETP activities.

Effect of modified dairy fat on fasting and postprandial haemostatic variables in healthy young men.

It has been suggested that milk fat, due to its content of saturated fatty acids, may have a thrombogenic effect. In the present study the fatty acid profile of milk fat was modified by changing the feeding regimens of cows and the effect on haemostatic variables of a diet containing the modified milk fat (M) was compared with that of a diet containing milk fat of typical Danish composition (D). In the modified fat 16% of the saturated fatty acid (C12-C16) content was replaced mainly by oleic acid. Eighteen subjects were fed on two strictly controlled isoenergetic diets containing 40% energy from total fat (30% energy from the test fats) for periods of 4 weeks in a study with a crossover design. Fasting samples were taken in the last week of each study period. Postprandial samples were taken on day 21, 3 h after lunch (n 18), and on the last day of the study 2, 4, 6 and 8 h after a fat load containing 1.2 g of one of the milk fats/kg body weight (n 8). After 4 weeks' dietary intervention fasting plasma factor VII coagulant (FVIIc) activity, tissue-type plasminogen activator (t-PA) activity, plasminogen activator inhibitor (PAI-1) antigen and beta-thromboglobulin did not differ between diets M and D. Postprandially FVIIc and t-PA activities increased (P < 0.001) and PAI-1 antigen and PAI-1 activity decreased (P < 0.001) as compared with fasting values, regardless of diet. After the fat load, the postprandial increase in FVIIc was marginally lower after diet M than diet D (diet effect, P < 0.05). In conclusion, the modified milk fat obtained by the applied feeding strategy had virtually the same effects on haemostatic variables as conventional milk fat.

Effect of modified dairy fat on postprandial and fasting plasma lipids and lipoproteins in healthy young men.

Fatty acid profile of milk fat can be modified by cow feeding strategies. Our aim was postprandially and after 4 wk to compare the effect of a modified milk fat (M diet) [with 16% of the cholesterolemic saturated fatty acid (C12-16) replaced by mainly oleic and stearic acids] with the effect of D diet, including a conventional Danish milk fat on plasma lipids and lipoproteins. A side effect of the cow feeding regime was a 5% (w/w) increase in trans fatty acid in M diet. Eighteen subjects were fed for two periods of 4 wk strictly controlled isoenergetic test diets with 40% of energy from total fat and the same content of dietary cholesterol in a randomized study with cross-over design. Contrary to expectations, fasting low density lipoprotein (LDL) cholesterol concentration did not differ after the experimental periods. However, M diet resulted in a higher fasting total triacylglycerol concentration compared to D diet (P = 0.009). Postprandial samples were taken at two different occasions (i) at day 21, after breakfast and lunch and (ii) on the last day of the study 2, 4, 6, and 8 h after a fat load. Postprandial plasma triacylglycerol and chylomicron triacylglycerol showed higher peak values after D diet than M diet (interaction effect, diet x times P < 0.05). In conclusion, M diet did not lower LDL cholesterol compared to D diet. Thus any cholesterol-lowering effect of oleic and stearic acids may have been obscured by the high content of cholesterol-raising saturated fatty acids in milk fat. A higher content of the trans fatty acids in M diet might have counteracted the cholesterol neutral/decreasing effect and increased plasma triacylglycerol.

Acute effect of high-fat meals rich in either stearic or myristic acid on hemostatic factors in healthy young men.

Suggestions have been made that saturated fatty acids with 12-18 carbon atoms, stearic acid (18:0) in particular, are prothrombogenic. These suggestions are based mainly on in vitro measurements. In the present study the effect of dietary fats high in stearic or myristic acid (14:0) on plasma triacylglycerol concentrations and key variables of blood aggregation (in vitro and in vivo), coagulation, and fibrinolysis was studied over 24 h in 10 healthy young men. For each dietary fat, two identical high-fat test meals were served: one in the morning (0 h) and one 8 h later, and blood samples were collected at 0, 2, 4, 6, 8, and 24 h. Both fats decreased platelet aggregation compared with fasting values. Stearic fat resulted in a tendency toward lower activity of plasminogen activator inhibitor 1 (PAI-1) than did myristic fat (P < 0.08). PAI-1 was also lower 24 h after consumption of either fat than initially (P < 0.05). Stearic fat, but not myristic fat, tended to cause some increase in factor VII coagulant activity and beta-thromboglobulin after 4 h. In conclusion, an acute prothrombotic effect of fats high in myristic and stearic acid was not confirmed.

Effect of fats high in individual saturated fatty acids on plasma lipoprotein[a] levels in young healthy men.

Plasma lipoprotein[a] (Lp[a]) is associated with atherogenesis and thrombogenesis. We examined how plasma Lp[a] in healthy young men was affected by fats high in stearic (C18), palmitic (C16), and lauric+myristic (C12+ C14) acid (experiment I, 15 subjects), and by fats high in myristic (C14) and palmitic (C16) acid (experiment II, 12 subjects). Strictly controlled isocaloric diets with 36% of energy from test fats were served in random order for 3 weeks separated by wash-out period(s). Diets high in C18 gave significantly higher levels of Lp[a] (51(12-560) mg/L) than diets high in C16 (38(12-533 mg/L) (P = 0.020) and C12 + C14 (34(12-534) mg/L) (P = 0.002). These differences were observed in several of the subjects in experiment I. In experiment II we saw no difference in plasma Lp[a] after diets high in C16 and C14. Our observations suggest that a fat high in stearic acid might affect Lp[a] in a different way than fats high in palmitic and myristic+lauric acid. Lp[a] concentrations were not associate with changes in tissue-plasminogen activator (t-PA) activity, factor VII coagualant activity, or plasma LDL cholesterol.

Dietary changes in fasting levels of factor VII coagulant activity (FVII:C) are accompanied by changes in factor VII protein and other vitamin K-dependent proteins.

The mechanisms behind dietary effects on fasting coagulant activity of factor VII (FVII:C) are not clarified. In the present study of 15 young volunteers, two experimental diets differing in composition of saturated fatty acids (C18:0 [diet S] or C12:0 + C14:0 [diet ML]) were served for 3 weeks each. Fasting blood samples were collected before and after the dietary regimen and analysed for triglycerides, FVII:C, and protein concentrations of FVII, FII, FX, protein C, CRP, albumin, fibrinogen, and F1 + 2. FVII:C was significantly reduced on diet S compared with diet ML. This was accompanied by a decrease in FVII protein, F1 + 2 and the vitamin K-dependent proteins FII, FX, and protein C. In contrast, no changes were observed in triglycerides, FVII:C/FVII:Ag, albumin and CRP. Fibrinogen was increased on diet S compared with diet ML. Our findings suggest that the change in fasting FVII:C was part of a general change in concentrations of vitamin K-dependent proteins.

Effect on blood lipids, coagulation, and fibrinolysis of a fat high in myristic acid and a fat high in palmitic acid.

The hypothesis that myristic acid (C14:0) has a stronger cholesterol-increasing potential than does palmitic acid is based on very few experimental observations. A randomized, strictly controlled dietary study was therefore designed to investigate the effect of a synthetic fat that was high in myristic acid, and palm oil, which is high in palmitic acid, on lipoproteins and hemostatic variables. Twelve men were served two diets (40% of energy as fat) with 41% of fat as myristic (diet M) or palmitic acid (diet P) for 3 wk with 1 mo between the two dietary schedules. Plasma HDL cholesterol was 8% higher with diet M than with diet P: 1.10 +/- 0.06 (mean +/- SEM) vs 1.01 +/- 0.05 mmol/L (P < 0.006). Diet M raised factor VII coagulant (F VIIc) activity to 98% (77-117%) vs 96% (71-109%) (medians and ranges) after diet P (P = 0.02). Total and LDL-cholesterol concentrations did not differ between the diets. In conclusion, the myristic acid test fat was not more cholesterolemic than was palm oil, but it did induce a minor rise in F VIIc activity.

Fat high in stearic acid favorably affects blood lipids and factor VII coagulant activity in comparison with fats high in palmitic acid or high in myristic and lauric acids.

The effect of fats high in individual, prevalent saturated dietary fatty acids on lipoproteins and hemostatic variables in young healthy subjects was evaluated in a randomized strictly controlled metabolic feeding study. Three experimental diets: shea butter (S; 42% stearic acid), palm oil (P; 43% palmitic palmitic acid), and palm-kernel oil with high-oleic sunflower oil (ML; 10% myristic acid, 30% lauric acid) were served to 15 men for 3 wk each, separated by washout periods. Diet S compared with diet P resulted in significant reduction in plasma cholesterol (22%) LDL cholesterol (26%), apolipoprotein B (18%), HDL cholesterol (12%), apolipoprotein A-I (13%), and a 13% lower factor VII coagulant activity (P = 0.001). Similar differences were observed between diets S and ML. In conclusion, intake of shea butter high in stearic acid favorably affects blood lipids and factor VII coagulant activity in young men, compared with fats high in saturated fatty acids with 12-16 carbons.