Subgram daily supplementation with docosahexaenoic acid protects low-density lipoproteins from oxidation in healthy men

ObjectiveTo determine the effect of supplementation with increasing doses of docosahexaenoic acid (DHA), as the only n-3 polyunsaturated fatty acid (PUFA), on low-density lipoprotein (LDL) redox status and oxidizability.MethodsTwelve healthy men aged 53–65 years ingested consecutive doses of DHA (200, 400, 800 and 1600 mg/day), each dose for two weeks.ResultsThe proportions of DHA increased dose-dependently in LDL phospholipids and cholesteryl esters, even after two weeks of supplementation with 200 mg/day DHA. The daily intake of 200, 400 and 800 mg DHA resulted in increased alpha-tocopherol concentrations, decreased MDA concentrations, and a longer lag time for copper-induced LDL oxidation. Supplementation with 1600 mg/day DHA had no effect on the above parameters. In plasma, concentrations of 4-hydroxy-hexenal, specifically derived from the peroxidation of n-3 fatty acids, significanty increased after 800 and 1600 mg DHA, representing 0.01% of plasma n-3 PUFAs, while 4-hydroxy-nonenal concentrations, derived from the peroxidation of n-6 fatty acids, did not change.ConclusionOur results clearly show that an intake of 200–800 mg/day DHA may have protective and antioxidant effects on LDL and could represent optimal doses for cardiovascular disease prevention in a healthy population.     

Dietary fatty acids and peripheral artery disease in adults

BackgroundPeripheral artery disease (PAD) is a debilitating condition involving atherosclerosis. Although saturated, monounsaturated and polyunsaturated fatty acids have strong associations with atherosclerosis, it is unclear if diets high in these fatty acids affect PAD.MethodsWe studied 6352 adults aged 40 years and older who participated in the U.S. National Health and Nutrition Examination Survey between 1999 and 2004. Ankle brachial index (ABI) was assessed by standardized blood pressure measurements, and we defined PAD as an ABI < 0.9. Fatty acid intake was assessed by validated 24-h dietary recall. We used multivariable linear and logistic regression to estimate associations between intakes of dietary saturated fatty acids (SFAs), monounsaturated fatty acids (MFAs), marine omega-3 fatty acids (N-3), linolenic acid (LNA), and omega-6 fatty acids (N-6) and ABI/PAD.ResultsThe prevalence and 95% confidence interval (CI) of PAD was 5.2% (95% CI 4.6–5.8).There were no associations between ABI and intakes of marine N-3 (p = 0.83) or N-6 (p = 0.19) in adjusted models. In contrast, LNA was associated with higher ABI (p = 0.04) and SFA tended to be associated with lower ABI (p = 0.06) in adjusted models. In addition, higher SFA was associated with a higher prevalence of PAD: adjusted odds ratio 1.30 (95% CI 1.01–1.67; p = 0.04) and a trend toward slower gait speed (p = 0.08).ConclusionIn this nationally representative sample, higher dietary intakes of LNA and SFAs were associated with higher and lower ABI, respectively. Prospective studies are needed to confirm the potential protective effects of dietary LNA and detrimental effects of dietary SFAs on PAD.     

Polyunsaturated fatty acids balance affects platelet NOX2 activity in patients with liver cirrhosis

BackgroundNADPH-oxidase-2 up-regulation has been suggested in liver damage perpetuation via an oxidative stress-mediated mechanism. n-6/n-3 polyunsaturated fatty acids ratio derangement has been reported in liver disease.AimTo explore polyunsaturated fatty acids balance and its interplay with platelet oxidative stress in liver cirrhosis.MethodsA cross-sectional study in 51 cirrhotic patients and sex- and age-matched controls was performed. Serum polyunsaturated fatty acids and oxidative stress markers (urinary isoprostanes and serum soluble NADPH-oxidase-2-derived peptide) were measured. The effect on platelet oxidative stress of n-6/n-3 polyunsaturated fatty acids ratio in vitro and in vivo (1-week supplementation with 3 g/daily n-3-polyunsaturated fatty acids) was tested.ResultsCompared to controls, cirrhotic patients had significantly higher n-6/n-3 polyunsaturated fatty acids ratio. n-6/n-3 polyunsaturated fatty acids ratio correlated significantly with disease severity and oxidative stress markers. In vitro experiments showed that in Child–Pugh C patients’ platelets incubation with low n-6/n-3 polyunsaturated fatty acids ratio resulted in dose-dependent decrease of radical oxigen species (−39%), isoprostanes (−25%) and NADPH-oxidase-2 regulation (−51%). n-3 polyunsaturated fatty acids supplemented patients showed significant oxidative stress indexes reduction.ConclusionsIn cirrhosis, n-6/n-3 polyunsaturated fatty acids imbalance up-regulates platelet NADPH-oxidase-2 with ensuing oxidative stress. Further study to evaluate if n-3 supplementation may reduce disease progression is warranted.     

Consuming a balanced high fat diet for 16 weeks improves body composition,inflammation and vascular function parameters in obese premenopausal women

ObjectiveInflammation, insulin resistance and vascular dysfunction characterize obesity and predict development of cardiovascular disease (CVD). Although women experience CVD events at an older age, vascular dysfunction is evident 10 years prior to coronary artery disease. Questions remain whether replacing SFA entirely with MUFA or PUFA is the optimal approach for cardiometabolic benefits. This study tested the hypotheses that: a) body composition, inflammation and vascular function would improve with a high fat diet (HFD) when type of fat is balanced as 1/3 SFA, 1/3 MUFA and 1/3 PUFA; and b) body composition, inflammation and vascular function would improve more when balanced HFD is supplemented with 18C fatty acids, in proportion to the degree of 18C unsaturation.MethodsObese premenopausal women were stabilized on balanced HFD and randomized to consume 9 g/d of encapsulated stearate (18:0), oleate (18:1), linoleate (18:2) or placebo.ResultsSignificant improvements occurred in fat oxidation rate (↑6%), body composition (%fat: ↓2.5 ± 2.1%; %lean: ↑2.5 ± 2.1%), inflammation (↓ IL-1α, IL-1β, 1 L-12, Il-17, IFNγ, TNFα, TNFβ) and vascular function (↓BP, ↓PAI-1, ↑tPA activity). When compared to HFD + placebo, HFD + stearate had the greatest effect on reducing IFNγ (↓74%) and HFD + linoleate had the greatest effect on reducing PAI-1 (↓31%).ConclusionsBalancing the type of dietary fat consumed (SFA/MUFA/PUFA) is a feasible strategy to positively affect markers of CVD risk. Moreover, reductions in inflammatory molecules involved in vascular function might be enhanced when intake of certain 18C fatty acids is supplemented. Long term effects need to be determined for this approach.     

Gender-specific inhibition of platelet aggregation following omega-3 fatty acid supplementation

Background and AimsIncreased platelet aggregation is a major risk factor for heart attacks, stroke and thrombosis. Long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA; eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA) reduce platelet aggregation; however studies in the published literature involving EPA and/or DHA supplementation have yielded equivocal results. Recent in vitro studies have demonstrated that inhibition of platelet aggregation by LCn-3PUFA is gender specific. We examined the acute effects of dietary supplementation with EPA or DHA rich oils on platelet aggregation in healthy male and females.Methods and ResultsA blinded placebo controlled trial involving 15 male and 15 female subjects. Platelet aggregation was measured at 0, 2, 5 and 24 h post-supplementation with a single dose of either a placebo or EPA or DHA rich oil capsules. The relationship between LCn-3PUFA and platelet activity at each time point was examined according to gender vs. treatment. EPA was significantly the most effective in reducing platelet aggregation in males at 2, 5 and 24 h post-supplementation (?11%, ?10.6%, ?20.5% respectively) whereas DHA was not effective relative to placebo. In contrast, in females, DHA significantly reduced platelet aggregation at 24 h (?13.7%) while EPA was not effective. An inverse relationship between testosterone levels and platelet aggregation following EPA supplementation was observed.ConclusionInteractions between sex hormones and omega-3 fatty acids exist to differentially reduce platelet aggregation. For healthy individuals, males may benefit more from EPA supplementation while females are more responsive to DHA.     

Serum phospholipid omega-3 polyunsaturated fatty acids and insulin resistance in type 2 diabetes mellitus and non-alcoholic fatty liver disease

AimsTo investigate the relationship between serum phospholipid omega-3 polyunsaturated fatty acids (ω-3 PUFAs) and insulin resistance (IR) in patients with type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD).Methods51 patients with T2DM and NAFLD (T2DM + NAFLD group), 50 with T2DM alone (T2DM group), 45 with NAFLD alone (NAFLD group), and 42 healthy control subjects (NC group) were studied. Serum ω-3 PUFA profiles were analyzed by gas chromatography, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyltransferase (GGT), and serum lipid concentrations were measured. Insulin resistance was assessed by the homeostasis model assessment method (HOMA-IR).ResultsHOMA-IR levels were higher in the T2DM + NAFLD group than in the T2DM, NAFLD and NC groups (p < 0.05), as were ALT, AST, GGT, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) concentrations (p < 0.05). Conversely, serum ω-3 PUFA levels were significantly lower in the T2DM + NAFLD group than in the other groups (p < 0.05). The ω-3 PUFA level was negatively correlated with HOMA-IR, TC, LDL-C and TG.ConclusionsSerum phospholipid ω-3 PUFA levels were significantly decreased in patients with T2DM and NAFLD, and were negatively related with insulin resistance. Thus, reduced ω-3 PUFAs may play an important role in the development of T2DM and NAFLD.     

Fatty acid profile of the erythrocyte membrane preceding development of Type 2 diabetes mellitus

Background and aimsThe respective roles of dietary fatty acids in the pathogenesis of diabetes are as yet unclear. Erythrocyte membrane fatty acid (EMFA) composition may provide an estimate of dietary fatty acid intake. This study investigates the relation between EMFA composition and development of Type 2 diabetes mellitus.Methods and resultsIn a nested case-referent design we studied 159 individuals tested as non-diabetic at baseline who after a mean observation time of 5.4 ± 2.6 years were diagnosed with Type 2 diabetes mellitus and 291 sex- and age-matched referents. Higher proportions of pentadecanoic acid (15:0) and heptadecanoic acid (17:0) were associated with a lower risk of diabetes. In accordance with earlier findings, higher proportions of palmitoleic (16:1 n-7), dihomo-γ-linolenic (20:3 n-6) and adrenic (22:4 n-6) acids were associated with increased risk, whereas linoleic (18:2 n-6) and clupanodonic (22:5 n-3) acids were inversely associated with diabetes. After adjustment for BMI, HbA1c, alcohol intake, smoking and physical activity the only significant predictors were 15:0 and 17:0 as protective factors and 22:4 n6 as risk factor.ConclusionIn accordance with previous studies, our results indicate that EMFA-patterns predict development of Type 2 diabetes mellitus. The inverse association with two saturated fatty acids, previously shown to reflect consumption of dairy products, is a new finding.     

Altered colonic mucosal availability of n-3 and n-6 polyunsaturated fatty acids in ulcerative colitis and the relationship to disease activity

Background and AimsThe polyunsaturated fatty acids (PUFA) arachidonic acid (AA, n-6) and eicosapentaenoic acid (EPA, n-3) are precursors of eicosanoids and other lipid mediators which have critical roles in inflammation. The mediators formed from the different PUFA have different potencies. We hypothesised that metabolic changes associated with colonic mucosal inflammation would modify the bioavailability of the eicosanoid precursors AA and EPA.MethodsColonic mucosa biopsies were obtained from patients with ulcerative colitis and from matched controls. Inflammation was graded endoscopically and histologically. Esterified and non-esterified fatty acids were determined within the biopsies using gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry, respectively.ResultsBiopsy samples were collected from 69 UC patients (54 providing both inflamed and non-inflamed mucosa) and 69 controls. Inflamed mucosa had higher AA (p < 0.001) and lower EPA (p < 0.010) contents and a higher AA:EPA ratio (p < 0.001). Inflamed mucosa also had higher docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) and lower linoleic acid (LA) and α-linolenic acid (α-LNA) contents (all p < 0.001), compared to non-inflamed and controls. There were significant correlations between severity of inflammation and contents of AA, DPA and DHA (positive correlations) and of LA, α-LNA and EPA (negative correlations).ConclusionsHigher AA, AA:EPA ratio, DPA and DHA and lower LA, α-LNA and EPA are seen in inflamed mucosa in UC and correlate with severity of inflammation. This suggests an alteration in fatty acid metabolism in the inflamed gut mucosa, which may offer novel targets for intervention and should be considered if nutritional strategies are used.     

Effects of soybean D-LeciVita product on serum lipids and fatty acid composition in type 2 diabetic patients with hyperlipidemia

Background and aimHyperlipidemia is one of the major risk factors of cardiovascular complication in diabetes. High intake of soy product has been suggested to prevent cardiovascular disease. The purpose of this study was to evaluate if dietary supplement of soybean D-LeciVita product, rich in polyunsaturated phospholipids (with 12% lecithin, 35% soy protein) affects serum lipids and serum and erythrocyte phospholipid fatty acid composition in type 2 diabetic patients.Methods and resultsForty-seven patients (men and post-menopausal women) with isolated hypertriglyceridemia (IHTG) and combined hyperlipidemia (CHL), aged 43–70 years, were given 15 g of D-LeciVita powder as a water suspension in a single evening dose during the follow-up period of 12 weeks. Patients kept their diabetic diet relatively constant. Treatment was associated with a significant (p ≤ 0.001) decrease in serum total cholesterol and triglyceride levels by 12% and 22%, respectively. LDL-cholesterol decreased by 16% and HDL-cholesterol increased by 11% (p ≤ 0.001). Our study shows a 27% decrease in LDL-cholesterol (p ≤ 0.001) and a 12% increase in HDL-cholesterol (p ≤ 0.01) in CHL type 2 diabetic patients. Triglyceride levels decreased in type 2 diabetic patients with IHTG and CHL by 29% and 13%, respectively (p ≤ 0.01 and p ≤ 0.05). Our results show decrease in SFA and increase in n-6 and n-3 PUFA in serum and erythrocyte phospholipids. SFA decreased and n-3 PUFA increased in serum and erythrocyte phospholipids in IHTG and CHL groups.ConclusionThe present study indicated that added to a regular diet, soybean D-LeciVita product (combination of soy protein and lecithin) is associated not only with lipid-lowering effects but also with more favorable serum phospholipids fatty acid profile in type 2 diabetic patients with hyperlipidemia.     

Effects of dietary saturated,monounsaturated and n-3 fatty acids on fasting lipoproteins,LDL size and post-prandial lipid metabolism in healthy subjects

BACKGROUND: The influence of the quality of dietary fat on some aspects of lipid metabolism-i.e. lipoprotein concentrations, post-prandial lipids and LDL size-is not completely understood, especially in healthy individuals. OBJECTIVES: Aim of this study was to evaluate the effects of different types of dietary fat (monounsaturated vs. saturated fatty acids, and n-3 or placebo supplementation) on fasting lipoproteins, LDL size and post-prandial lipids in healthy people. DESIGN: One hundred and sixty-two individuals were randomly assigned to follow two isoenergetic diets, one rich in saturated fatty acids (SFA diet) and the other in monounsaturated fatty acids (MUFA diet). Each group was further randomised to receive supplementation with fish oil (3.6 g/day) or placebo. RESULTS: The type of diet significantly affected LDL cholesterol and triacylglycerol content, which was higher with the SFA diet and lower with the MUFA diet. The changes between the two diets were statistically significant for cholesterol (P<0.01) and triacylglycerol (P<0.03). VLDL cholesterol and triacylglycerol were significantly reduced and LDL cholesterol significantly increased by fish oil supplementation. Plasma triacylglycerol was significantly lower in those taking n-3 fatty acids, also 1 and 3 h after a test-meal. Neither type of diet nor n-3 supplementation affected LDL size. CONCLUSIONS: A moderate substitution of saturated fatty acids with monounsaturated fatty acids has beneficial effects on lipid metabolism also in healthy individuals. A moderate supplementation of long-chain n-3 fatty acids in healthy individuals reduces both fasting and post-prandial triacylglycerol concentrations but increases LDL cholesterol, irrespective of the type of diet.     

Apolipoprotein E enrichment of immuno-separated chylomicron and chylomicron remnants following saturated fatty acids

AimWe examined the effect of meal fatty acids on lipid and apolipoprotein concentrations of very low density lipoprotein (VLDL) and chylomicron/chylomicron remnants in lipid fractions with a Svedberg flotation rate (S_f) 60–400 and S_f 20–60.Methods and resultsSix healthy middle-aged men received in random order mixed meals enriched with saturated (SFA), polyunsaturated (PUFA) or monounsaturated (MUFA) fatty acids on 3 occasions. VLDL and chylomicron/chylomicron remnants in the lipid fractions were separated by immunoaffinity chromatography against apo B-100. In the S_f 60–400 chylomicron/chylomicron remnants, triacylglycerol and cholesterol concentrations were significantly lower following PUFA compared with SFA and MUFA (P ≤ 0.05). Apolipoprotein (apo) E responses were significantly higher after SFA in chylomicron/chylomicron remnants and VLDL compared with PUFA and MUFA (P < 0.007). However, apo B responses (particle number) were higher following MUFA than SFA (P = 0.039 for chylomicron/chylomicron remnants). Composition of the chylomicron/chylomicron remnants (expressed per particle) revealed differences in their triacylglycerol and apo E contents; in the S_f 60–400 fraction, SFA-rich chylomicron/chylomicron remnants contained significantly more triacylglycerol than MUFA (P = 0.028), more apo E than PUFA- and MUFA-rich particles (P < 0.05) and in the S_f 20–60 fraction, more apo E than MUFA (P = 0.009).ConclusionThere are specific differences in the composition of chylomicron/chylomicron remnants formed after saturated compared with unsaturated fatty acid-rich meals which could determine their metabolic fate in the circulation and subsequent atherogenicity.     

Body mass interacts with fat quality to determine the postprandial lipoprotein response in healthy young adults

Background and aimsPostprandial lipemia predicts the evolution of cardiovascular disease. Obesity is associated with an increase in the magnitude of postprandial lipemia. Our objective was to evaluate the influence of body mass index (BMI) on the effects of acute ingestion of different types of fat on the postprandial lipemic response.Methods and resultsTwenty-one healthy men followed a 4-week baseline diet and then consumed three fat-loaded meals that included 1 g fat/kg body wt (65%fat) according to a randomized crossover design. The compositions of the three meals were olive oil meal (22% saturated fatty acids (SFA), 38% monounsaturated fatty acids (MUFA), 4% polyunsaturated fatty acids (PUFA)); butter meal (35% SFA, 22% MUFA, 4% PUFA); walnuts meal (20% SFA, 24% MUFA, 16% PUFA, and 4% α-linolenic acid). Higher-weight (HW) subjects (BMI greater than the median 26.18 kg/m², n = 11) presented higher incremental area under the curve (iAUC) for triglycerides (TG), both in large- and small-TG rich lipoproteins (TRL) than lower-weight (LW) subjects (BMI < 26.18 kg/m², n = 10) (p < 0.05), and a similar trend for plasma TG (p = 0.084). Moreover, HW subjects presented higher concentrations for small TRL-cholesterol and small TRL-TG in different timepoints of the postprandial lipemia after the intake of enriched walnuts or butter meals compared with the olive oil-enriched meal (p < 0.05) No significant differences were observed between the three types of meals in the postprandial response of LW subjects.ConclusionHW subjects present a greater postprandial response than LW subjects, and they benefit from the consumption of monounsaturated fatty acids from olive oil, to lower their levels of TRL particles during the postprandial state.     

A protein-enriched low glycemic index diet with omega-3 polyunsaturated fatty acid supplementation exerts beneficial effects on metabolic control in type 2 diabetes

AimsThe current study aims to investigate practicability and effects of a combined dietary intervention with increased relative protein content supplemented with omega-3 polyunsaturated fatty acids (PUFA) on metabolic control and inflammatory parameters in a real life situation in type 2 diabetes patients.MethodsIn this observational study we advised thirty mostly obese patients with type 2 diabetes to follow a protein-enriched diet with carbohydrates of low glycemic index (low GI) and moderate fat reduction supplemented with omega-3 PUFA for 24 weeks. Primary efficacy parameter was the change in HbA1c; secondary parameters included changes in systemic inflammation (measured by ultrasensitive C-reactive protein, usCRP), body weight, waist circumference, fat mass. The study is registered at clinicaltrials.gov (NCT01474603).ResultsThe dietary intervention significantly reduced the primary efficacy variable HbA1c from a baseline value of 63 ± 11 mmol/mol to 59 ± 14 mmol/mol (P = 0.033) and 56 ± 12 mmol/mol (P = 0.001) after 12 and 24 weeks, respectively. In addition, usCRP decreased significantly at 24 weeks (P = 0.039). Waist circumference, an important indicator for cardiometabolic-risk and silent inflammation, decreased from baseline 116.0 ± 14.1 cm to 114.9 ± 13.5 cm (P = 0.019), 114.0 ± 14.4 cm (P = 0.001), and 112.7 ± 13.4 cm (P = 0.049), after 3, 12 and 24 weeks, respectively.ConclusionCounseling a protein enriched and low glycemic index diet supplemented with long-chain omega-3 PUFA in a real-life clinical setting improves glycemic control and also reduces waist circumference and silent inflammation in overweight or obese patients with type 2 diabetes.     

Short term effects of energy restriction and dietary fat sub-type on weight loss and disease risk factors

Background and aimsDecreasing energy intake relative to energy expenditure is the indisputable tenet of weight loss. In addition to caloric restriction modification of the type of dietary fat may provide further benefits. The aim of the present study was to examine the effect of energy restriction alone and with dietary fat modification on weight loss and adiposity, as well as on risk factors for obesity related disease.Methods and resultsOne-hundred and fifty overweight men and women were randomized into a 3 month controlled trial with four low fat (30% energy) dietary arms: (1) isocaloric (LF); (2) isocaloric with 10% polyunsaturated fatty acids (LF-PUFA); (3) low calorie (LF-LC) (?2 MJ); (4) low calorie with 10% PUFA (LF-PUFA-LC). Primary outcomes were changes in body weight and body fat and secondary outcomes were changes in fasting levels of leptin, insulin, glucose, lipids and erythrocyte fatty acids. Changes in dietary intake were assessed using 3 day food records. One-hundred and twenty-two participants entered the study and 95 completed the study. All groups lost weight and body fat (P < 0.0001 time effect for both), but the LC groups lost more weight (P = 0.026 for diet effect). All groups reduced total cholesterol levels (P < 0.0001 time effect and P = 0.017 intervention effect), but the LC and PUFA groups were better at reducing triacylglycerol levels (P = 0.056 diet effect). HDL increased with LF-LC and LF-PUFA but not with LF-PUFA-LC (0.042 diet effect). The LF and LF-LC groups reported greater dietary fat reductions than the two PUFA groups (P = 0.043).ConclusionEnergy restriction has the most potent effect on weight loss and lipids, but fat modification is also beneficial when energy restriction is more modest.     

Effet des acides gras polyinsaturés N-3 sur la modulation in vitro des lymphocytes T et le statut redox chez les femmes obèses hypertendues

ObjectivesDeepen our knowledge of the immune system alterations associated with obesity-related hypertension and demonstrate that polyunsaturated fatty acids can enhance the proliferation and their profile oxidant/antioxidant and subsequently involved in the strategy prevention and treatment in obese hypertensives.MethodsT cells are isolated from the blood of the control and obese women with hypertension the University Hospital of Tlemcen (Algeria), these cells are incubated in the presence of a synthetic mixture of PUFA to 30 μM (DHA/EPA/LA) and stimulated by mitogens for 48 hours. The cells are counted and used to assess intracellular oxidative status. The biochemical parameters are determined by the use of plasma.ResultsIn obese women with hypertension, a significant increase in plasma levels of (glucose, uric acid, creatinine, urea, total cholesterol and triglycerides) compared to controls. In addition, decreased cell proliferation, basal or stimulated by Con A was observed in obese women with hypertension compared with controls. The mixture of PUFA to 30 μM reduced lymphoproliferation as well in obese women with hypertension than in controls. The rates in malondialdéhyde (MDA) and protein carbonyl lymphocytes are elevated in hypertensive obese women. PUFA supplementation to 30 μM seems correct this redox status in hypertensive obese since rates in protein carbonyl, are similar to those of controls.ConclusionThe mixture of PUFA (n-3 and n-6) can modulate the activity of T lymphocyte proliferation and correct the intracellular redox status in hypertensive obese women.     

Effects of omega-3 polyunsaturated fatty acids on metabolically active hormones in patients post-myocardial infarction

BackgroundLong-chain omega-3 polyunsaturated fatty acids (PUFA) supplementation is used as a therapeutic secondary prevention strategy among post-myocardial infarction (MI) patients. The effects of omega-3 PUFA on markers of energy homeostasis among post-MI patients are unclear.MethodsWe investigated the effects of Omacor (a pharmaceutical capsule formulation of highly refined, concentrated omega-3 PUFA; Solvay Healthcare, Southampton, UK; 1 g/day) in addition to usual care (cardiovascular therapy) in a pilot randomised study of 35 post-MI men. Following randomisation to Omacor (n = 16), or ‘usual care’ controls (n = 19), fasting levels of insulin, non-esterified fatty acids (NEFA), triglycerides, glucose and adipocytokines (adiponectin, leptin and tumour necrosis factor (TNF)-α), as indices of markers of energy homeostasis, were measured at baseline and after 3-month treatment.ResultsThere were no baseline differences in age, body mass index, blood pressure, fasting triglycerides, plasma glucose, NEFA and adipocytokines between the two treatment arms (P = 0.07). There were no significant changes in metabolically active hormones within groups after 3-month treatment. Across arms, the direction of baseline to follow-up changes in insulin levels were significantly different (P =  0.03), with a mean increase with Omacor (+ 3.39 mU/ml) and a decrease among controls (− 17.6 mU/ml), without associated deteriorating changes in triglycerides, NEFA or plasma glucose.ConclusionThis pilot study suggests that Omacor had little effect on glycaemic control among male post-MI patients. However, Omacor was associated with raised insulin levels, compared to usual care; thus, a metabolic basis for the cardioprotective action of Omacor, outside of its lipid lowering effects, merits further investigation.     

The G-250A polymorphism in the hepatic lipase gene promoter is associated with changes in hepatic lipase activity and LDL cholesterol: The KANWU Study

Background and aimsHepatic lipase (HL) catalyzes the hydrolysis of triglycerides and phospholipids from lipoproteins, and promotes the hepatic uptake of lipoproteins. A common G-250A polymorphism in the promoter of the hepatic lipase gene (LIPC) has been described. The aim was to study the effects of the G-250A polymorphism on HL activity, serum lipid profile and insulin sensitivity.Methods and resultsAltogether 151 healthy subjects (age 49 ± 8 years, BMI 26.5 ± 3.0 kg/m²) were randomly assigned for 3 months to an isoenergetic diet containing either a high proportion of saturated fatty acids (SFA diet) or monounsaturated fatty acids (MUFA diet). Within groups there was a second random assignment to supplements with fish oil (3.6 g n-3 FA/day) or placebo. At baseline, the A-250A genotype was associated with high serum LDL cholesterol concentration (P = 0.030 among three genotypes). On the MUFA diet carriers of the A-250A genotype presented a greater decrease in LDL cholesterol concentration than subjects with other genotypes (P = 0.007 among three genotypes). The rare -250A allele was related to low HL activity (P < 0.001 among three genotypes). The diet did not affect the levels of HL activity among the genotypes.ConclusionThe A-250A genotype of the LIPC gene was associated with high LDL cholesterol concentration, but the MUFA-enriched diet reduced serum LDL cholesterol concentration especially in subjects with the A-250A genotype.     

The Mediterranean and CHO diets decrease VCAM-1 and E-selectin expression induced by modified low-density lipoprotein in HUVECs

Background and AimThe oxidative modifications of low-density lipoprotein (LDL) are crucial for the atherosclerosis process. The aim of this study was to determine if the minimally modified LDL, obtained after the ingestion of three different diets, produce differential effects on the vascular cell adhesion molecule-1 (VCAM-1) and E-selectin expression in human umbilical endothelial cells (HUVECs).Methods and ResultsTwenty healthy young males were exposed to three dietary periods. Each period lasted four weeks. During the first period, all subjects consumed a saturated fat (SFA) enriched diet (38% fat, 20% SFA). The second and third dietary periods were administered following a randomized crossover design: a low fat high carbohydrates diet (CHO diet) and a Mediterranean diet. LDL particles, isolated during each dietary period, were oxidized by exposure to UV light and incubated for 48 h with HUVEC. Thereafter, 100 U/mL of TNF-α was added and incubation continued for 6 h. Cellular ELISA determined adhesion molecules expression. Lag time, propagation rate and total amounts of formed conjugated dienes were calculated in LDL incubated with 10 μmol/L Cu²⁺. When compared to the SFA diet, LDL isolated from the Mediterranean and CHO diets induced a lower expression of VCAM-1 and E-selectin in HUVECS (P < 0.007). There were no differences between both lipid lowering diets. However, lag time of LDL from the Mediterranean diet was higher than with the CHO diet (P < 0.042). This parameter was inversely correlated with E-selectin expression (r = − 0.497; P < 0.04).ConclusionOur results suggest that both the Mediterranean and CHO diets may decrease the pro-inflammatory environment induced by modified LDL in endothelial cells.     

Progressing Insights into the Role of Dietary Fats in the Prevention of Cardiovascular Disease

Dietary fats have important effects on the risk of cardiovascular disease (CVD). Abundant evidence shows that partial replacement of saturated fatty acids (SAFA) with unsaturated fatty acids improves the blood lipid and lipoprotein profile and reduces the risk of coronary heart disease (CHD). Low-fat diets high in refined carbohydrates and sugar are not effective. Very long-chain polyunsaturated n-3 or omega-3 fatty acids (n-3 VLCPUFA) present in fish have multiple beneficial metabolic effects, and regular intake of fatty fish is associated with lower risks of fatal CHD and stroke. Food-based guidelines on dietary fats recommend limiting the consumption of animal fats high in SAFA, using vegetable oils high in monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), and eating fatty fish. These recommendations are part of a healthy eating pattern that also includes ample intake of plant-based foods rich in fiber and limited sugar and salt.     

The efficacy of omega-3 fatty acid supplementation on plasma homocysteine and malondialdehyde levels of type 2 diabetic patients

Background and aimsCardiovascular diseases are the major cause of mortality among diabetic patients. The concentration of malondialdehyde (MDA) and homocysteine is believed to play a role in cardiovascular diseases. Omega-3 fatty acid supplementation could be effective in some diabetes complications and in the control of the glycemic index. However, it may increase lipid peroxidation. The objective of this study was to determine the effect of omega-3 fatty acids on the concentration of homocysteine and MDA in diabetic patients.Methods and resultsA randomized double-blind, placebo-controlled clinical trial was conducted on 81 patients with type 2 diabetes. The patients were randomly assigned to either the treatment or control groups. Each subject received three capsules of omega-3 fatty acids or a placebo every day for a period of 2 months. The two groups were similar in terms of body mass index and food intake. At the beginning of the study and after 2 months of supplementation their levels of HbA₁c, homocysteine, MDA, C-reactive protein (CRP), total cholesterol, LDL-cholesterol and fasting blood sugar (FBS) were determined. Due to omega-3 fatty acid supplementation, homocysteine was changed significantly in both treatment and control groups up to ?3.10 μmol/L and 0.10 μmol/L respectively, and HbA₁c decreased by 0.75% in the treatment group and increased by 0.26% in the control group. However, the changes in fasting blood sugar (FBS), malondialdehyde (MDA), C-reactive protein (CRP), total cholesterol and LDL-cholesterol levels were not significant.ConclusionThe consumption of omega-3 fatty acid supplements (3 g/day) for 2 months decreases the levels of homocysteine in diabetic patients with no change in FBS, MDA and CRP levels.