Fatty fish consumption reduces lipophilic index in erythrocyte membranes and serum phospholipids.

BACKGROUND AND AIMS: Lipophilic index (LI) has been introduced to assess the overall fatty acid lipophilicity and as a simple estimate of membrane fluidity. However, little is known on effect of diet on LI. We tested if Camelina sativa oil (CSO) high in ALA, fatty fish (FF) or lean fish (LF) affect LI as compared to control diet and, secondarily, if the LI is associated with HDL lipids and functionality and LDL lipidome. METHODS AND RESULTS: We used data from two randomized clinical trials. The AlfaFish intervention lasted 12 weeks and 79 subjects with impaired glucose tolerance were randomized to FF, LF, CSO or control group. In the Fish trial, 33 subjects with myocardial infarction or unstable ischemic heart attack were randomized to FF, LF or control group for 8 weeks. LI was calculated from erythrocyte membrane fatty acids in AlfaFish and from serum phospholipids in Fish trial. HDL lipids were measured using high-throughput proton nuclear magnetic resonance spectroscopy. There was a significant decrease in LI in the FF group in the AlfaFish (fold change 0.98 ± 0.03) and in the Fish trial (0.95 ± 0.04) and the decrease differed from that of control group in both trials and from CSO group in the AlfaFish study. There were no significant changes in LI in LF or CSO groups. The mean diameter of HDL particles and concentration of large HDL particles were inversely associated with LI. CONCLUSION: FF consumption decreased LI indicating better membrane fluidity in subjects with impaired glucose tolerance or coronary heart disease.

Longitudinal associations of serum fatty acid composition with type 2 diabetes risk and markers of insulin secretion and sensitivity in the Finnish Diabetes Prevention Study.

PURPOSE: To examine the longitudinal associations of serum fatty acid composition with type 2 diabetes, insulin secretion and insulin sensitivity over several years. METHODS: We conducted a prospective cohort study derived from the randomized Finnish Diabetes Prevention Study. Total serum fatty acid composition was measured using gas chromatography in 407 overweight, middle-aged people with impaired glucose tolerance at baseline (1993-1998) and annually during the intervention period (1994-2000). Longitudinal associations of 20 fatty acids and three desaturase activities (Δ5 (20:4n-6/20:3n-6, D5D), Δ6 (18:3n-6/18:2n-6, D6D), stearoyl-CoA desaturase-1 (16:1n-7/16:0, SCD-1)) with type 2 diabetes incidence, and estimates of insulin sensitivity (Matsuda), secretion (ratio of insulin and glucose concentrations) and ß-cell function (disposition index) by an oral glucose tolerance test were analyzed using Cox regression and linear mixed models. We validated estimated D5D and D6D using a known FADS1 gene variant, rs174550. RESULTS: The baseline proportions of 20:5n-3, 22:5n-3 and 22:6n-3, and D5D were associated with lower incidence of type 2 diabetes during a median follow-up of 11 years (HR per 1SD: 0.72, 0.74, 0.73, 0.78, respectively, P ≤ 0.01). These long-chain omega-3 fatty acids and D5D were associated with higher insulin sensitivity in subsequent years but not with disposition index. Saturated, monounsaturated and trans fatty acids and 18:3n-3, 18:2n-6, SCD-1 and D6D were inconsistently associated with type 2 diabetes or related traits. CONCLUSIONS: Serum long-chain omega-3 fatty acids and D5D predicted lower type 2 diabetes incidence in people at a high risk of diabetes attending to an intervention study; a putative mechanism behind these associations was higher insulin sensitivity.

Diet, insulin secretion and insulin sensitivity--the Dose-Responses to Exercise Training (DR's EXTRA) Study (ISRCTN45977199).

Intakes of saturated fat (SF) and dietary fibre, body mass and physical activity are all associated with the incidence of type 2 diabetes mellitus. Their relative importance for the maintenance of normal glucose metabolism is not fully known. In a population-based sample of 1114 individuals, aged 58-78 years, dietary intakes were assessed by 4 d food records and cardiorespiratory fitness as maximal oxygen uptake. Insulin secretion, insulin sensitivity, the early-phase disposition index (DI30) and the total disposition index (DI120) were assessed based on an oral glucose tolerance test. Linear associations were modelled using linear regression. Combined effects were studied by introducing SF and fibre intakes, as well as cardiorespiratory fitness and waist circumference (WC) as dichotomised variables in general linear models. Intakes of dietary fibre and whole-grain bread were positively associated with insulin sensitivity, independent of physical fitness and WC. In women, dietary fibre intake was also positively associated with DI30. The negative association of high WC with DI30 was attenuated by a combination of low SF intake and high cardiorespiratory fitness. In conclusion, dietary fibre and a combination of low SF intake and high cardiorespiratory fitness may contribute to the maintenance of normal glucose metabolism, independent of WC.

Carnitine Intake and Serum Levels Associate Positively with Postnatal Growth and Brain Size at Term in Very Preterm Infants.

Carnitine has an essential role in energy metabolism with possible neuroprotective effects. Very preterm (VPT, <32 gestation weeks) infants may be predisposed to carnitine deficiency during hospitalization. We studied the associations of carnitine intake and serum carnitine levels with growth and brain size at term equivalent age (TEA) in VPT infants. This prospective cohort study included 35 VTP infants admitted to Kuopio University Hospital, Finland. Daily nutrient intakes were registered at postnatal weeks (W) 1 and 5, and serum carnitine levels were determined at W1, W5, and TEA. The primary outcomes were weight, length, and head circumference Z-score change from birth to TEA, as well as brain size at TEA in magnetic resonance imaging. Carnitine intake at W1 and W5, obtained from enteral milk, correlated positively with serum carnitine levels. Both carnitine intake and serum levels at W1, W5, and TEA showed a positive correlation with weight, length, and head circumference Z-score change and with brain size at TEA. In linear models, independent positive associations of carnitine intake and serum carnitine levels with length and head circumference Z-score change and brain size at TEA were seen. In VPT infants, sufficient carnitine intake during hospitalization is necessary since it is associated with better postnatal growth and larger brain size at term age.

Feasibility of a lifestyle intervention in early pregnancy to prevent deterioration of glucose tolerance.

BACKGROUND: In conjunction with the growing prevalence of obesity and the older age of pregnant women gestational diabetes (GDM) is a major health problem.The aim of the study was to evaluate if a lifestyle intervention since early pregnancy is feasible in improving the glucose tolerance of women at a high-risk for GDM in Finland. METHODS: A 75-g oral glucose tolerance test (OGTT) was performed in early pregnancy (n = 102). Women at high risk for GDM (n = 54) were randomized at weeks 8-12 from Apr 2005 to May 2006 to a lifestyle intervention group (n = 27) or to a close follow-up group (n = 27). An OGTT was performed again at weeks 26-28 for the lifestyle intervention and close follow-up groups. RESULTS: The values of the OGTT during the second trimester did not differ between the lifestyle intervention and close follow-up groups. In the lifestyle intervention group three women had GDM in the second trimester and respectively one woman in the close follow up group. Insulin therapy was not required in both groups. The intervention resulted in somewhat lower weight gain 11.4 ± 6.0 kg vs. 13.9 ± 5.1 kg, p = 0.062, adjusted by the prepregnancy weight. CONCLUSIONS: Early intervention with an OGTT and simple lifestyle advice is feasible. A more intensive lifestyle intervention did not offer additional benefits with respect to glucose tolerance, although it tended to ameliorate the weight gain. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01130012.

Lipidomic changes of LDL after consumption of Camelina sativa oil, fatty fish and lean fish in subjects with impaired glucose metabolism-A randomized controlled trial.

BACKGROUND: There is little knowledge on the effects of alpha-linolenic acid (ALA) and n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) on the LDL lipidome and aggregation of LDL particles. OBJECTIVE: We examined if consumption of Camelina sativa oil (CSO) as a source of ALA, fatty fish (FF) as a source of n-3 LCPUFA and lean fish (LF) as a source of fish protein affect the lipidome of LDL as compared to a control diet. METHODS: Participants with impaired glucose tolerance (39 women and 40 men) were randomized to 4 study groups (CSO providing 10 g/d ALA, FF and LF [both 4 fish meals/wk] and control limiting their fish and ALA intake) in a 12-week, parallel trial. Diets were instructed and dietary fats were provided to the participants. The lipidome of LDL particles isolated from samples collected at baseline and after intervention was analyzed with electrospray ionization-tandem mass spectrometry. RESULTS: In the CSO group, the relative concentrations of saturated and monounsaturated cholesteryl ester species in LDL decreased and the species with ALA increased. In the FF group, LDL phosphatidylcholine (PC) species containing n-3 LCPUFA increased. There was a significant positive correlation between the change in total sphingomyelin and change in LDL aggregation, while total PC and triunsaturated PC species were inversely associated with LDL aggregation when all the study participants were included in the analysis. CONCLUSION: Dietary intake of CSO and FF modifies the LDL lipidome to contain more polyunsaturated and less saturated lipid species. The LDL surface lipids are associated with LDL aggregation.

Intake of Camelina Sativa Oil and Fatty Fish Alter the Plasma Lipid Mediator Profile in Subjects with Impaired Glucose Metabolism - A Randomized Controlled Trial.

n-3 and n-6 polyunsaturated fatty acids (PUFAs) and their lipid mediator metabolites are associated with inflammation. We investigated the effect of dietary intake of plant- and animal-derived n-3 PUFAs and fish protein on the circulatory concentrations of lipid mediators. Seventy-nine subjects with impaired fasting glucose who completed the controlled dietary intervention after randomization to the fatty fish (FF, n=20), lean fish (LF, n=21), Camelina sativa oil (CSO, n=18) or control group (n=20) for 12 weeks were studied. Lipid mediator profiling from fasting plasma samples before and after the intervention was performed by liquid chromatography-mass spectrometry (LC-MS/MS). The FF diet increased concentrations of 18-hydroxyeicosapentaenoic acid (18-HEPE) and 4- and 17-hydroxydocosahexaenoic acid (4-, 17-HDoHE) derived from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), respectively. Concentrations of lipid mediators derived from α-linolenic acid (ALA) increased and arachidonic acid (AA) derived 5-iso prostaglandin F2α-VI decreased in the CSO group. There were no significant changes in lipid mediators in the LF group. The dietary intake of both plant and animal-based n-3 PUFAs increased circulatory concentrations of lipid mediators with potential anti-inflammatory properties.

The effect of fatty or lean fish intake on inflammatory gene expression in peripheral blood mononuclear cells of patients with coronary heart disease.

BACKGROUND: Little is known about the effect of fish consumption on gene expression of inflammation-related genes in immune cells in coronary heart disease (CHD). AIM OF THE STUDY: We sought to evaluate the effect of a fatty fish (FF) or a lean fish (LF) diet on the modulation of inflammatory and endothelial function-related genes in peripheral blood mononuclear cells (PBMCs) of subjects with CHD, and its association with serum fatty acid (FA) profile and lipid metabolic compounds. METHODS: Data from 27 patients randomized into an 8-week FF (n = 10; mean +/- SD: 4.3 +/- 0.4 portions of fish per week), LF (n = 11; 4.7 +/- 1.1 portions of fish per week), or control diet (n = 6; 0.6 +/- 0.4 portions of fish per week) were analyzed. The mRNA expression was measured using real-time PCR. RESULTS: The effect of the intervention on the mRNA expression of the genes studied did not differ among groups. In the FF group, however, the decrease in arachidonic acid to eicosapentaenoic acid (AA:EPA) ratio in cholesterol ester and phospholipid fractions strongly correlated with the change in IL1B mRNA levels (r (s) = 0.60, P = 0.06 and r (s) = 0.86, P = 0.002, respectively). In the LF group, the decrease in palmitic acid and total saturated FAs in cholesterol esters correlated with the change in intercellular cell adhesion molecule-1 (ICAM1) expression (r (s) = 0.64, P = 0.04 for both). Circulating levels of soluble ICAM-1 decreased only in the LF group (P < 0.05). CONCLUSIONS: The intake of FF or LF diet did not alter the expression of inflammatory and endothelial function-related genes in PBMCs of patients with CHD. However, the decrease in AA:EPA ratio in serum lipids in the FF group may induce an anti-inflammatory response at mRNA levels in PBMCs. A LF diet might benefit endothelial function, possibly mediated by the changes in serum FA composition.

The effect of different sources of fish and camelina sativa oil on immune cell and adipose tissue mRNA expression in subjects with abnormal fasting glucose metabolism: a randomized controlled trial.

BACKGROUND/OBJECTIVES: Molecular mechanisms linking fish and vegetable oil intakes to their healthy metabolic effects may involve attenuation of inflammation. Our primary aim was to examine in a randomized controlled setting whether diets enriched in fatty fish (FF), lean fish (LF) or ALA-rich camelina sativa oil (CSO) differ in their effects on the mRNA expression response of selected inflammation-related genes in peripheral blood mononuclear cells (PBMCs) and subcutaneous adipose tissue (SAT) in subjects with impaired fasting glucose. SUBJECTS/METHODS: Samples from 72 participants randomized to one of the following 12-week intervention groups, FF (n = 19), LF (n = 19), CSO (n = 17) or a control group (n = 17), were available for the PBMC study. For SAT, 39 samples (n = 8, n = 10, n = 9, n = 12, respectively) were available. The mRNA expression was measured at baseline and 12 weeks by TaqMan® Low Density Array. RESULTS: In PBMCs, LF decreased ICAM1 mRNA expression (P < 0.05), which was different (P = 0.06, Bonferroni correction) from the observed increase in the FF group (P < 0.05). Also, compared to the control group, LF decreased ICAM1 mRNA expression (P < 0.05). Moreover, the change in ICAM1 mRNA expression correlated positively with the intake of FF (P < 0.05) and negatively with the intake of LF (P < 0.05), independently of study group. A diet enriched in CSO, a rich source of alpha-linolenic acid (ALA), decreased PBMC IFNG mRNA expression (P < 0.01). The intake of CSO in the CSO group, but not the increase in plasma ALA proportions, correlated inversely with the IFNG mRNA expression in PBMCs (P = 0.08). In SAT, when compared with the control group, the effect of FF on decreasing IL1RN mRNA expression was significant (P < 0.03). CONCLUSION: We propose that CSO intake may partly exert its benefits through immuno-inflammatory molecular regulation in PBMCs, while modulation of ICAM1 expression, an endothelial/vascular-related gene, may be more dependent on the type of fish consumed.

Camelina sativa Oil, Fatty Fish, and Lean Fish Do Not Markedly Affect Urinary Prostanoids in Subjects with Impaired Glucose Metabolism.

Dietary fatty acids are suggested to affect oxidative stress; however, results from interventions have been inconclusive. The aim was to examine if fatty fish, lean fish, and Camelina sativa oil (CSO) affect the urinary prostanoid levels in subjects with impaired glucose metabolism. Altogether 79 participants aged 43-72 years completed a randomized controlled study lasting 12 weeks. There were four parallel groups, fatty fish, lean fish (four fish meals/week in both), CSO providing 10 g/day alpha-linolenic acid (ALA), and control diet with limited fish and ALA containing oil consumption. Urinary prostanoids (prostaglandin F2α , 5-F2t -isoprostanes and 15-F2t -isoprostane metabolites, isofuran, 8-F3t -isoprostanes, and 4-(RS)-4-F4t -neuroprostane) of 72 participants (age: mean (±SD) 58.9 ± 6.5 years; body mass index: 29.3 ± 2.5 kg/m2 ) collected over 12-h were measured using liquid chromatography tandem-mass spectrometry. Plasma phospholipid fatty acids were determined using gas chromatography. Our study showed that the proportion of ALA in plasma phospholipids increased in the CSO group (overall difference among the groups p-value <0.001). In the fatty fish group, proportions of eicosapentaenoic and docosahexaenoic acids increased (overall p-value <0.001 for both). Prostaglandin F2α was higher in the CSO group than in the control group (p < 0.05), however, there were no other significant changes in urinary excretion of other prostanoids among the study groups. At baseline, arachidonic acid in plasma phospholipids was positively (r = 0.247, p < 0.05) and ALA negatively (r = -0.326, p < 0.05) associated with urinary total isoprostanes. In conclusion, CSO, fatty fish, and lean fish consumption do not cause major changes in oxidative stress markers in subjects with impaired glucose tolerance.

Effects of fatty and lean fish intake on blood pressure in subjects with coronary heart disease using multiple medications.

BACKGROUND: Intake of fish and long-chain n-3 fatty acids has been of wide interest due to their beneficial effects on cardiovascular risk factors and lower coronary heart disease (CHD) risk. AIM OF THE STUDY: The aim of this pilot study was to examine the effects of fatty fish and lean (white) fish on fatty acid composition of serum lipids and cardiovascular risk factors in subjects with CHD using multiple drugs for this condition. METHODS: The study was an 8-week controlled, parallel intervention. Inclusion criteria were myocardial infarction or unstable ischemic attack, age under 70 years, use of betablockers and presence of sinus rhythm. The subjects were randomized to one of the following groups: 4 meals/week fatty fish (n = 11), 4 meals/week lean fish (n = 12) and control diet including lean meat (n = 10). RESULTS: The mean (+/-SD) of reported fish meals per week was 4.3 +/- 0.4, 4.7 +/- 1.1 and 0.6 +/- 0.4 in the groups, respectively. The proportions of eicosapentaenoic and docosahexaenoic acids in serum lipids increased in the fatty fish group only (P < 0.05). Systolic and diastolic blood pressure levels decreased in the lean fish group (0 vs. 8 week: 3.5 +/- 3.2 and 4.6 +/- 3.6%, respectively, P < 0.05). Serum total triglyceride concentration did not significantly change. HDL cholesterol concentration change differed among groups but without significant post hoc differences. Apolipoprotein A-1 concentration decreased in the control group (0 vs. 8 week, P < 0.05). Coagulation factors, 25-hydroxy vitamin D, and heart rate variability (24 h Holter) did not change among the groups. CONCLUSIONS: Our results suggest that intake of lean fish at least four times per week could reduce blood pressure levels in CHD patients.

Intake of Fatty Fish Alters the Size and the Concentration of Lipid Components of HDL Particles and Camelina Sativa Oil Decreases IDL Particle Concentration in Subjects with Impaired Glucose Metabolism.

SCOPE: Intake of long-chain n-3 PUFAs affects the lipoprotein subclass profile, whereas the effect of shorter chain n-3 PUFAs remains unclear. We investigated the effect of fish and camelina sativa oil (CSO) intakes on lipoprotein subclasses. METHODS AND RESULTS: Altogether, 79 volunteers with impaired glucose metabolism were randomly assigned to CSO, fatty fish (FF), lean fish (LF), or control group for 12 weeks. Nuclear magnetic resonance spectroscopy was used to determine lipoprotein subclasses and their lipid components. The average HDL particle size increased in the FF group (overall p = 0.032) as compared with the control group. Serum concentrations of cholesterol in HDL and HDL2 (overall p = 0.024 and p = 0.021, respectively) and total lipids and phospholipids in large HDL particles (overall p = 0.012 and p = 0.019, respectively) increased in the FF group, differing significantly from the LF group. The concentration of intermediate-density lipoprotein (IDL) particles decreased in the CSO group (overall p = 0.033) as compared with the LF group. CONCLUSION: Our study suggests that FF intake causes a shift toward larger HDL particles and increases the concentration of lipid components in HDL, which may be associated with the antiatherogenic properties of HDL. Furthermore, CSO intake decreases IDL particle concentration. These changes may favorably affect cardiovascular risk.

Camelina Sativa Oil, but not Fatty Fish or Lean Fish, Improves Serum Lipid Profile in Subjects with Impaired Glucose Metabolism-A Randomized Controlled Trial.

SCOPE: The aim of the study is to examine whether lean fish (LF), fatty fish (FF), and camelina sativa oil (CSO), a plant-based source of alpha-linolenic acid (ALA), differ in their metabolic effects in subjects with impaired glucose metabolism. METHODS AND RESULTS: Altogether 79 volunteers with impaired fasting glucose, BMI 25-36 kg m-2 , age 43-72 years, participated in a 12-week randomized controlled trial with four parallel groups, that is, the FF (four fish meals/week), LF (four fish meals/week), CSO (10 g d-1 ALA), and control (limited intakes of fish and sources of ALA) groups. The proportions of eicosapentaenoic acid and DHA increase in plasma lipids in the FF group, and the proportion of ALA increase in the CSO group (p < 0.0001 for all). In the CSO group, total and LDL-cholesterol (C) concentrations decrease compared with the FF and LF groups; LDL-C/HDL-C and ApoB/ApoA-I ratios decrease compared with the LF group. There are no significant changes in glucose metabolism or markers of low-grade inflammation. CONCLUSIONS: A diet enriched in CSO improves serum lipid profile as compared with a diet enriched in FF or LF in subjects with impaired fasting glucose, with no differences in glucose metabolism or concentrations of inflammatory markers.

Gene-diet interaction of a common FADS1 variant with marine polyunsaturated fatty acids for fatty acid composition in plasma and erythrocytes among men.

SCOPE: Limited information exists on how the relationship between dietary intake of fat and fatty acids in erythrocytes and plasma is modulated by polymorphisms in the FADS gene cluster. We examined gene-diet interaction of total marine PUFA intake with a known gene encoding Δ-5 desaturase enzyme (FADS1) variant (rs174550) for fatty acids in erythrocyte membranes and plasma phospholipids (PL), cholesteryl esters (CE), and triglycerides (TG). METHODS AND RESULTS: In this cross-sectional study, fatty acid compositions were measured using GC, and total intake of polyunsaturated fat from fish and fish oil was estimated using a food frequency questionnaire in a subsample (n = 962) of the Metabolic Syndrome in Men Study. We found nominally significant gene-diet interactions for eicosapentaenoic acid (EPA, 20:5n-3) in erythrocytes (pinteraction = 0.032) and for EPA in plasma PL (pinteraction = 0.062), CE (pinteraction = 0.035), and TG (pinteraction = 0.035), as well as for docosapentaenoic acid (22:5n-3) in PL (pinteraction = 0.007). After excluding omega-3 supplement users, we found a significant gene-diet interaction for EPA in erythrocytes (pinteraction < 0.003). In a separate cohort of the Kuopio Obesity Surgery Study, the same locus was strongly associated with hepatic mRNA expression of FADS1 (p = 1.5 × 10(-10) ). CONCLUSION: FADS1 variants may modulate the relationship between marine fatty acid intake and circulating levels of long-chain omega-3 fatty acids.

Effect of a 2-y dietary and physical activity intervention on plasma fatty acid composition and estimated desaturase and elongase activities in children: the Physical Activity and Nutrition in Children Study.

BACKGROUND: Evidence on the effects of lifestyle interventions on plasma fatty acid composition in children is limited. OBJECTIVE: We investigated the effects of a dietary and physical activity intervention on plasma fatty acid composition of cholesteryl esters (CEs) and phospholipids and estimated desaturase and elongase activities in children. DESIGN: We conducted a 2-y controlled dietary and physical activity intervention based on Finnish nutrition and physical activity recommendations in a population sample of 506 children aged 6-8 y. We assessed plasma fatty acid composition by gas chromatography and estimated desaturase and elongase activities as the ratio of product fatty acids to precursor fatty acids. We analyzed data by using linear mixed models adjusted for age and sex. RESULTS: The proportion of total polyunsaturated fatty acids (PUFAs) in CEs tended to increase in the intervention group compared with the control group (P = 0.007 for group × time interaction). The proportion of total PUFAs in phospholipids (P = 0.019 for group × time interaction) and the proportion of linoleic acid in CEs (P = 0.038 for group × time interaction) decreased in the control group. The proportion of α-linolenic acid in CEs (P < 0.001 for group × time interaction) increased and in phospholipids (P = 0.015 for group × time interaction) tended to increase in the intervention group. The proportion of stearic acid in CEs decreased in the intervention group (P = 0.001 for group × time interaction). The proportion of oleic acid in CEs (P = 0.002 for group × time interaction) increased and in phospholipids (P = 0.023 for group × time interaction) tended to increase in the control group. Estimated elongase activity in CEs decreased in the control group (P = 0.050 for group × time interaction). Intervention had no effect on estimated desaturase activities. CONCLUSIONS: Dietary and physical activity intervention had a beneficial effect on plasma fatty acid composition in children by preventing the decrease in the proportion of total PUFAs and linoleic acid and by increasing the proportion of α-linolenic acid. This study was registered at clinicaltrials.gov as NCT01803776.

Black currant seed oil and fish oil supplements differ in their effects on fatty acid profiles of plasma lipids, and concentrations of serum total and lipoprotein lipids, plasma glucose and insulin.

European diets provide a suboptimal intake of eicosapentaenoic (20:5n3) and docosahexaenoic (22:6n3) acids, which are derived mainly from fish oils. The present study indicates that black currant seed oil, which contains 14.5% alpha-linolenic (18:3n3), 12.6% gamma-linolenic (18:3n6), 47.5% linoleic (18:2n6) and 2.7% stearidonic (18:4n3) acids, could potentially serve as alternative to fish oil as a n3 fatty acid source. Fifteen healthy females participated in a randomized, double-blind, crossover study including two 4-week periods with either 3 g/day of black currant seed oil or 2.8 g/day of fish oil separated by a 4-week washout period. The results show that black currant seed oil supplementation increased the proportion of 18:3n6 in triacylglycerols (TAG) and cholesteryl esters (CE), and that of dihomo-gamma-linolenic (20:3n6) in TAGs, CEs and glycerophospholipids (GPL) (P<.05). Proportion of 18:3n6 was higher (P<.05) after black currant seed oil than after fish oil in TAGs and CEs, and that of 20:3n6 in TAGs, CEs and GPLs. Black currant seed oil supplementation caused only minor changes in the proportions of 20:5n3 or 22:6n3. Serum levels of LDL cholesterol were lower (P<.05) after black currant seed oil compared to fish oil. Plasma glucose concentration decreased during the fish oil supplementation (P<.05).

Association of the fatty acid profile of serum lipids with glucose and insulin metabolism during 2 fat-modified diets in subjects with impaired glucose tolerance.

BACKGROUND: Both the amount and quality of dietary fat can modify glucose and insulin metabolism. OBJECTIVE: The objective was to examine the relation between serum lipid fatty acids and glucose metabolism before and after the consumption of a diet enriched in either monounsaturated (Mono diet) or polyunsaturated (Poly diet) fatty acids. DESIGN: After consuming a high-saturated-fat run-in diet for 3 wk, 31 subjects with impaired glucose tolerance were randomly counseled to consume the Mono [40% fat; 11%, 19%, and 8% of energy as saturated, monounsaturated, and polyunsaturated fatty acids (S:M:P), respectively] or the Poly (34% fat; S:M:P of 11%:10%:10%) diet for 8 wk. Serum lipid fatty acids were measured, and an intravenous-glucose-tolerance test was performed at baseline and at 8 wk. RESULTS: At baseline, a higher glucose effectiveness (S(G)) was associated with higher proportions of oleic (r = 0.57, P = 0.04) and alpha-linolenic (r = 0.64, P = 0.01) acids in phospholipids. An increase in the proportions of oleic and alpha-linolenic acids in phospholipids was associated with a decrease in fasting plasma glucose [r = -0.53 (P = 0.002) and r = -0.47 (P = 0.009), respectively]. An increase in the S(G) was associated with an increase in the proportion of oleic acid (r = 0.55, P = 0.004) and with a decrease in that of arachidonic acid (r = -0.40, P = 0.04) in phospholipids. CONCLUSIONS: The beneficial changes in fasting plasma glucose and in the S(G) during the Mono diet were associated with alterations in the proportions of oleic, alpha-linolenic, and arachidonic acids in phospholipids.

Influence of hydrogenated fat and butter on CVD risk factors: remnant-like particles, glucose and insulin, blood pressure and C-reactive protein.

Dietary trans fatty acids/partially-hydrogenated fat has been associated with increased risk of developing cardiovascular disease (CVD), possibly greater than predicted from changes in lipoprotein levels. To explore this issue further potential risk factors were assessed in subjects provided with each of six diets in randomized order containing as the major source of fat: soybean oil, semi-liquid margarine, soft margarine, shortening, traditional stick margarine or butter. Plasma fatty acid profiles reflected diet, with triglyceride and phospholipid subfractions affected to a greater extent than cholesteryl ester. Non-fasting LDL-cholesterol levels were 144+/-27, 141+/-27, 146+/-26, 148+/-30, 151+/-29 and 165+/-31 mg/dl (P<0.001) and total cholesterol/HDL-cholesterol ratios were 5.50+/-1.25, 5.54+/-1.50, 5.69+/-1.29, 5.82+/-1.40, 6.11+/-1.30 and 5.94+/-1.43 (P=0.011), respectively, whereas other lipoprotein levels were not significantly different. Remnant-like particles levels were unaffected by dietary fat, either in the fasting or non-fasting state. Differences in fasting insulin and glucose levels were small and would not be predicted to have a large impact on glucose homeostasis. There was no significant effect of dietary fat type on C-reactive protein levels or blood pressure. These data suggest that, as previously demonstrated, the major CVD risk factor adversely affected by dietary trans fatty acids/partially-hydrogenated fat is LDL-cholesterol levels and total cholesterol/HDL-cholesterol ratios.

Positional distribution of decanoic acid: effect on chylomicron and VLDL TAG structures and postprandial lipemia.

Although medium-chain FA (MCFA) are mainly absorbed via the portal venous system, they are also incorporated into chylomicron TAG; therefore, the positional distribution of MCFA in TAG is likely to affect their metabolic fate. We studied chylomicron and VLDL TAG structures, as well as the magnitude of postprandial lipemia, after two oral fat loads containing decanoic acid (10:0) predominantly at the sn-1(3),2 (MML) or at the sn-1,3 positions (MLM) of TAG in a randomized, double-blind, crossover clinical trial with 10 healthy, normal-weight volunteers. An MS-MS method was used to analyze TAG regioisomers. The position of decanoic acid in chylomicron TAG reflected its position in the TAG ingested, and TAG with none, one, two, or three decanoic acid residues were detected after ingestion of both fats. More (P < 0.05) 30:0 and 38:1 TAG (acyl carbons:double bonds) and fewer 46:5, 54:5, and 54:4 TAG were found in chylomicrons after ingestion of MML than after MLM. The VLDL TAG composition did not differ between the fat loads but did change (P < 0.05) 2 to 6 h after ingestion of both fats. No statistical differences were seen between the fat loads in areas under the plasma, chylomicron, or VLDL TAG response curves or in FFA concentrations. Thus, the positional distribution of MCFA in TAG affects their metabolic fate, but the magnitude of postprandial lipemia does not seem to be dependent on the positional distribution of MCFA in the ingested fat.

Chylomicron and VLDL TAG structures and postprandial lipid response induced by lard and modified lard.

Alterations in chylomicron and VLDL TAG and the magnitude of postprandial lipemia were studied in healthy volunteers after two meals of equal FA composition but different TAG FA positional distribution. Molecular level information of individual lipoprotein TAG regioisomers was obtained with a tandem MS method. The incremental area under the response curve of VLDL TAG was larger (P = 0.021) after modified lard than after lard. In plasma TAG, the difference did not quite reach statistical significance (P = 0.086). In general, there were less TAG with palmitic acid in the sn-2 position and more TAG with oleic acid in the sn-2 position in chylomicrons than in fat ingested. From 1.5 to 8 h postprandially, the proportion of individual chylomicron TAG was constant or influenced by TAG M.W. VLDL TAG regioisomerism was similar regardless of the positional distribution of fat ingested. Significant alterations were seen in VLDL TAG FA, in M.W. fractions, and in individual regioisomers with respect to time. The TAG sn-14:0-18:1-18:1 + sn-18:1-18:1-14:0, sn-16:0-16:1-18:1 + sn-18:1-16:1-16:0, and sn-16:1-18:1-18:1 + sn-18:1-18:1-16:1 decreased (P < 0.05); and sn-16:0-16:0-18:2 + sn-18:2-16:0-16:0, sn-16:0-16:0-18:1 + sn-18:1-16:0-16:0, sn-16:0-18:1-16:0, and sn-16:0-18:1-18:2 + sn-18:2-18:1-16:0 increased (P < 0.05) after both meals. In conclusion, positional distribution of TAG FA was found to affect postprandial lipid metabolism in healthy normolipidemic subjects.