Fish Oil Fatty Acids Research Articles

Chew on This: Persistent Organic Pollutants May Promote Insulin Resistance Syndrome

Animal studies indicate some persistent organic pollutants (POPs) may be endocrine disruptors and suggest similar health risks for humans. Recent studies have further suggested an association between exposure to POPs and the prevalence of type 2 diabetes. Now an experimental animal study reports evidence of a causal link between POP exposure and insulin resistance syndrome, a cluster of metabolic disorders—including type 2 diabetes—that are marked by sustained high blood sugar [EHP 118:465–471; Ruzzin et al.]. POPs accumulate in fatty tissue, where they can remain for years because they are not easily broken down. Fatty fish are a potential source of POP exposure in many human populations. However, n-3 polyunsaturated fatty acids in fish oil may have beneficial health effects, possibly including protective effects on insulin resistance, that could counterbalance any adverse effects of POPs in fatty fish. In the current study, rats were exposed for 28 days to high-fat diets that contained either crude fish oil (from farmed Atlantic salmon) or fish oil that was refined to remove POPs. As expected, the crude fish oil contained much higher levels of POPs than the refined oil. Gene expression profile comparisons of the livers of the 2 treatment groups showed that POP exposure disrupted lipid homeostasis. Rats on the unrefined fish oil diet gained more weight overall and had increased triacylglycerol, diacylglycerol, and total cholesterol levels compared with rats fed refined fish oil. They also showed impaired insulin action in response to the high-fat diet, whereas the high-fat diet did not seem to cause insulin resistance in the rats fed refined fish oil. Further analysis revealed a reduction in the ability of insulin to stimulate glucose uptake in adipocytes treated with a mixture of POPs that was comparable to the mixture of chemicals in crude fish oil. Adipocyte responses to insulin varied with exposures to different mixtures of individual POPs. The authors conclude that dietary exposure to POPs may be a risk factor for insulin resistance and associated metabolic disorders. Furthermore, the metabolic effects of POP exposures exacerbated deleterious effects of a high-fat diet on rats and appeared to negate protective effects of n-3 polyunsaturated fatty acids on insulin resistance.

Rapid quantitation of fish oil fatty acids and their ethyl esters by FT‐NIR models

AbstractConsumption of fish oil and dietary supplements containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has steadily increased because of their reported health benefits. A rapid procedure based on Fourier Transform Near Infrared Spectroscopy (FT‐NIR) models was developed for analysis of fish oil and their ethyl ester derivatives to replace the time consuming GC method. Inclusion of fish oil or ethyl esters containing varied concentrations of OA, EPA, and DHA into the FT‐NIR classification models made possible their classification and quantification. Accurate GC analysis is essential in developing reliable quantitative models since FT‐NIR is matrix dependent. Development of FT‐NIR models based on 30 m PEG capillary GC column results, as recommended by the official GC method for analysis of marine oils, proved problematic, since these columns did not resolve many geometric isomers compared to 100 m highly polar cyanopropyl polysiloxane columns. Depending on the content of geometric isomers in fish oils and ethyl esters, the levels of long‐chain n‐3 PUFA would be overestimated if the model used were based on the results from a 30 m column. The FT‐NIR method was found to be applicable to all fish oil and ethyl ester samples, except when fatty acids were outside the range examined, or contaminants were present. The FT‐NIR method was applicable to analysis of in‐plant intermediates provided contaminants were absent, or identified so they could be incorporated into the model. The FT‐NIR method was suitable to evaluate the shelf life of n‐3 PUFA concentrates.

Toxicity of unsaturated fatty acids to the biohydrogenating ruminal bacterium, Butyrivibrio fibrisolvens

BackgroundHealth-promoting polyunsaturated fatty acids (PUFA) are abundant in forages grazed by ruminants and in vegetable and fish oils used as dietary supplements, but only a small proportion of PUFA finds its way into meat and milk, because of biohydrogenation in the rumen. Butyrivibrio fibrisolvens plays a major role in this activity. The aim of this study was to investigate the mechanisms by which PUFA affect the growth of B. fibrisolvens, how PUFA are metabolized and the metabolic response to growth in the presence of PUFA.ResultsLinoleic acid (LA; cis-9, cis-12-18:2) and α-linolenic acid (LNA; cis-9, cis-12, cis-15-18:3) increased the lag phase of B. fibrisolvens JW11, LNA having the greater effect. Growth was initiated only when the PUFA had been converted to vaccenic acid (VA; trans-11-18:1). The major fish oil fatty acids, eicosapentaenoic acid (EPA; 20:5(n-3)) and docosahexaenoic acid (DHA; 22:6(n-3)), were not metabolized and prevented growth. Cellular integrity, as determined fluorimetrically by propidium iodide (PI) ingression, was affected as much by 18:1 fatty acids, including VA, as 18:2 fatty acids. The methyl esters of LNA, LA, EPA and DHA had no effect on growth or other measurements. The ATP pool decreased by 2/3 when LA was added to growing bacteria, whereas most acyl CoA pools decreased by >96%.ConclusionsIt was concluded that biohydrogenation occurs to enable B. fibrisolvens to survive the bacteriostatic effects of PUFA, and that the toxicity of PUFA is probably mediated via a metabolic effect rather than disruption of membrane integrity.

The detection and influence of food soils on microorganisms on stainless steel using scanning electron microscopy and epifluorescence microscopy

A range of food soils and components (complex [meat extract, fish extract, and cottage cheese extract]; oils [cholesterol, fish oil, and mixed fatty acids]; proteins [bovine serum albumin (BSA), fish peptones, and casein]; and carbohydrates [glycogen, starch, and lactose]) were deposited onto 304 2B finish stainless steel surfaces at different concentrations (10–0.001%). Scanning electron microscopy (SEM) and epifluorescence microscopy were used to visualise the cell and food soil distribution across the surface. Epifluorescence microscopy was also used to quantify the percentage of a field covered by cells or soil. At 10% concentration, most soils, with the exception of BSA and fish peptone were easily visualised using SEM, presenting differences in gross soil morphology and distribution. When soil was stained with acridine orange and visualised by epifluorescence microscopy, the limit of detection of the method varied between soils, but some (meat, cottage cheese and glycogen) were detected at the lowest concentrations used (0.001%). The decrease in soil concentration did not always relate to the surface coverage measurement. When 10% food soil was applied to a surface with Escherichia coli and compared, cell attachment differed depending on the nature of the soil. The highest percentage coverage of cells was observed on surfaces with fish extract and related products (fish peptone and fish oil), followed by carbohydrates, meat extract/meat protein, cottage cheese/casein and the least to the oils (cholesterol and mixed fatty acids). Cells could not be clearly observed in the presence of some food soils using SEM. Findings demonstrate that food soils heterogeneously covered stainless steel surfaces in differing patterns. The pattern and amount of cell attachment was related to food soil type rather than to the amount of food soil detected. This work demonstrates that in the study of conditioning film and cell retention on the hygienic properties of surfaces, SEM may not reveal the presence of retained conditioning film, and thus methods such as epifluorescence microscopy should also be used. This is an essential facet to the methodology design of future work carried out in our laboratories on the effectiveness of the removal of cells and conditioning films from surfaces using different cleaning regimes.

Interfacial tension of marine lipids in contact with high pressure carbon dioxide

Abstract Interfacial tension (IFT) of fish oil triglycerides (TG) and fatty acid ethyl esters (FAEE) in contact with carbon dioxide (CO2) was measured according to the pendant drop method at 40, 55 and 70 °C and pressures up to 25 MPa. The IFT of both TG and FAEE decreased substantially with CO2 pressure. The IFT of FAEE vanished at elevated pressures, whereas that of TG decreased to a fairly constant level of about 2 mN/m. The IFT was correlated using a model taking into account the density, pressure and temperature of CO2, thereby facilitating the calculation of the ideal pendant drop volume as well as the surface excess concentration of CO2. In the pressure range studied, the pendant drop volume for FAEE decreased with pressure, whereas for TG it increased at elevated presssures due to the predominant effect of buoyancy. Furthermore, the change in IFT over time was determined at 55 °C for TG in contact with CO2 at pressures up to 11.4 MPa showing a decrease of IFT over time at low pressures, whereas at higher pressures it remained nearly constant. IFT influences drop formation as well as the disintegration of falling films thereby affecting the performance of separation processes.

Incorporated Fish Oil Fatty Acids Prevent Action Potential Shortening Induced by Circulating Fish Oil Fatty Acids

Increased consumption of fatty fish, rich in omega-3-polyunsaturated fatty acids (ω3-PUFAs) reduces the severity and number of arrhythmias. Long-term ω3-PUFA-intake modulates the activity of several cardiac ion channels leading to cardiac action potential shortening. Circulating ω3-PUFAs in the bloodstream and incorporated ω3-PUFAs in the cardiac membrane have a different mechanism to shorten the action potential. It is, however, unknown whether circulating ω3-PUFAs in the bloodstream enhance or diminish the effects of incorporated ω3-PUFAs. In the present study, we address this issue. Rabbits were fed a diet rich in fish oil (ω3) or sunflower oil (ω9, as control) for 3 weeks. Ventricular myocytes were isolated by enzymatic dissociation and action potentials were measured using the perforated patch-clamp technique in the absence and presence of acutely administered ω3-PUFAs. Plasma of ω3 fed rabbits contained more free eicosapentaenoic acid (EPA) and isolated myocytes of ω3 fed rabbits contained higher amounts of both EPA and docosahexaenoic acid (DHA) in their sarcolemma compared to control. In the absence of acutely administered fatty acids, ω3 myocytes had a shorter action potential with a more negative plateau than ω9 myocytes. In the ω9 myocytes, but not in the ω3 myocytes, acute administration of a mixture of EPA + DHA shortened the action potential significantly. From these data we conclude that incorporated ω3-PUFAs into the sarcolemma and acutely administered ω3 fatty acids do not have a cumulative effect on action potential duration and morphology. As a consequence, patients with a high cardiac ω3-PUFA status will probably not benefit from short term ω3 supplementation as an antiarrhythmic therapy.

Potential Effects of Omega-3 Fatty Acid Supplements in the Prevention of Type 2 Diabetes: A Critical Appraisal of Data from Randomized Clinical Trials

Emerging evidence has suggested favorable effects of marine omega-3 fatty acids on glucose homeostasis, lipid metabolism, endothelial function, and chronic inflammation, which could contribute individually or synergistically to the development of type 2 diabetes (T2D). With increasing prevalence of use of fish oil supplements and increasing fortification of the food supply with marine omega-3 fatty acids in the general population, it will be critically important to assess the overall balance of benefits and risks of omega-3 fatty acid supplements on glucose tolerance and diabetes. This article aims to summarize the evidence from available randomized clinical trials on the potential effects of fish oil and/or omega-3 fatty acid supplements among both nondiabetic and diabetic participants. Overall, the evidence for the beneficial or deleterious effects of fish oil supplements on insulin sensitivity has been inconsistent, with limited randomized trial data involving small trials of short duration. However, dietary recommendation of taking omega-3 fatty acids for prevention of T2D or diabetic complications may ultimately only be resolvable by definitive data from future large-scale clinical trials that include T2D as a primary outcome in a general

The impact of age on the postprandial vascular response to a fish oil-enriched meal

Although chronic fish oil intervention had been shown to have a positive impact on vascular reactivity, very little is known about their acute effects during the postprandial phase. Our aim was to examine the impact of a fish oil-enriched test meal on postprandial vascular reactivity in healthy younger ( < 50 years) v. older ( > or = 50 years) men. Vascular reactivity was measured at baseline (0 h), 2 and 4 h after the meal by laser Doppler iontophoresis and blood samples taken at 0 and 4 h for the measurement of plasma lipids, total nitrite, glucose and insulin. Acetylcholine- (ACh, endothelial-dependent vasodilator) and sodium nitroprusside (SNP, endothelial-independent vasodilator)-induced reactivities were greater at 4 h than at baseline or 2 h in the younger men (P < 0.04). These changes were not observed in the older men. Comparison of the male groups revealed significantly greater responses to ACh (P = 0.006) and SNP (P = 0.05) at 4 h in the younger compared with the older males. Postprandial NEFA concentrations were also greater at 4 h in the younger compared with the older men (P = 0.005), with no differences observed for any of the other analytes. Multiple regression analysis revealed age to be the most significant predictor of both ACh and SNP induced reactivity 4 h after the meal. In conclusion, the ingestion of a meal enriched in fish oil fatty acids was shown to improve postprandial vascular reactivity at 4 h in our younger men, with little benefit evident in our older men.

Density of marine lipids in equilibrium with carbon dioxide

The density of marine lipids in equilibrium with carbon dioxide (CO 2) was determined using a view cell equipped with a novel spring balance based on Archimedes’ principle. The densities of fish oil triglycerides (TG) and fish oil fatty acid ethyl esters (FAEE) were measured at pressures ranging from 0.1 to about 25 MPa and temperatures of 40, 55 and 70 °C. In the pressure and temperature ranges investigated, the density increased with pressure and decreased with temperature. The density increase from atmospheric pressure to about 25 MPa at temperatures of 40, 55 and 70 °C was 4.1, 3.2, 2.7% and 5.3, 4.0, 3.6% for TG and FAEE, respectively. Volumetric expansion of fish oil TG and FAEE saturated with CO 2 was determined at 40 °C and pressures ranging from 0.1 to 22 MPa. With increasing pressure a relative volume change of up to 38 and 67% was observed for TG and FAEE, respectively. The density and volumetric expansion of lipids in equilibrium with CO 2 are important for optimal design of high pressure processes involving mass and momentum transfer.

Acute Fish Oil and Soy Isoflavone Supplementation Increase Postprandial Serum (n-3) Polyunsaturated Fatty Acids and Isoflavones but Do Not Affect Triacylglycerols or Biomarkers of Oxidative Stress in Overweight and Obese Hypertriglyceridemic Men

Chronic consumption of fish and fish oil high in (n-3) PUFA reduces triacylglycerols (TG) but may increase oxidative stress, whereas consumption of soy isoflavones may reduce oxidative stress. Elevated serum TG and oxidative stress are considered cardiovascular disease (CVD) risk factors, but the effects of acute (n-3) PUFA and soy isoflavones on these CVD risk factors are unknown. The purpose of the study was to determine the effects of acutely supplementing a high-fat, high-fructose meal with fish oil and isoflavone placebo (FO) and fish oil placebo and soy isoflavones (ISO). In a randomized, double-blind, placebo-controlled, crossover study, 10 overweight or obese men consumed a high-fat, high-fructose meal with 4 dietary supplement combinations: fish oil placebo and isoflavone placebo (placebo); fish oil and isoflavone placebo (FO); fish oil placebo and isoflavones (ISO); and fish oil and isoflavones (FO + ISO). Serum collected at baseline and at 2, 4, and 6 h postprandially was analyzed for fatty acids, isoflavones, TG, and oxidative stress biomarkers (lipid hydroperoxides, oxidized-LDL, total antioxidant status). FO significantly increased serum (n-3) PUFA and ISO increased serum isoflavones. The study meal significantly increased serum total fatty acids and TG without affecting oxidative stress biomarkers. Serum TG and oxidative stress biomarkers did not differ between treatments. The FO and ISO were bioavailable but did not attenuate the postprandial rise in serum TG. Neither the study meal nor the FO or ISO induced significant changes in oxidative stress biomarkers. The current study adds to a limited literature on the acute effects of FO and ISO interventions on postprandial biomarkers of CVD risk.

Omega-3 Fatty Acids in Metabolism, Health, and Nutrition and for Modified Animal Product Foods

<h2>ABSTRACT</h2> Fatty acids, n-3 as well as n-6, are essential for normal physiological functioning and for the health of humans and all domestic species. It is important to emphasize an adequate linolenic acid (LNA) intake; the n-6:n-3 fatty acid ratio is not a useful concept, and it detracts from increasing absolute intakes of n-3 PUFA. In humans, when LNA is consumed in adequate amounts and without excessive n-6 fatty acids, conversion to eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids can maintain normal physiological functioning and health. However, conversion of LNA to EPA is more limited in humans than in rodent models, and conversion to DHA is even more limited. Stearidonic acid bypasses the limiting step in synthesis of EPA, but not DHA, from LNA. Therefore, development of gene-modified oil crops to increase content of stearidonic acid supply holds promise to increase EPA synthesis in humans. Quantitative synthesis of EPA and DHA from LNA in domestic animals has not been reported, but conversion is limited in these as well, although perhaps not for some aquatic species. In humans, evidence is clear that increased intake of the fish oil fatty acids, especially DHA, will improve physiological and health outcomes during pregnancy and lactation, stresses of the immune system, cardiovascular disease, cancer, and some mental and emotional conditions. At least 200 mg DHA should be consumed daily by pregnant and lactating women. Certain feed supplements increase the n-3 fatty acid content of animal products, including eggs, meat from major domestic species, and milk. Feeding flax (linseed or linseed oil) increases LNA content of products 2- to 3-fold, and in some products, EPA is also increased, with the exception of eggs, in which DHA, but not EPA, is increased. The increase is adequate to have a positive effect on the n-3 fatty acid intake of the general public. To change EPA, and especially DHA, significantly in animal products, fish oil or marine algae products must be fed. To achieve 2- to 3-fold increases in ruminant tissues and milk, supplementation with rumen-protected linseed or marine oil products is necessary. At higher levels of n-3 PUFA incorporation, effects on product quality (oxidative stability, sensory characteristics) and costs of production and segregation of modified from conventional products in the production and distribution streams must be considered. It seems possible that niche markets for products containing greater amounts of n-3 fatty acids can be developed without expensive protection processes and risks of decreased product quality.

Apparent digestibility of lipid and fatty acids in fish oil, poultry fat and vegetable oil diets by Atlantic halibut, Hippoglossus hippoglossus L.

An experiment was conducted to determine the apparent digestibility coefficients (ADC) of lipid and fatty acids of 5 experimental diets containing 18% lipid from the following sources: herring oil (HO), poultry fat (PF), flaxseed (FxO), canola (CO) and sunflower (SO) oils. Cholestane and chromic oxide were used as inert digestibility markers. Juvenile halibut (109.5±27.6 g) were held in tanks equipped with fecal collection columns and fed the experimental diets for 2 weeks. The average lipid ADC (%) of FxO, CO, and SO diets were 94.8±0.7, 93.4±0.5 and 93.3±0.2, respectively, and these values were higher than the ADC of HO (89.7±0.1) and PF (89.8±1.5) diets. The apparent digestibility of saturated fatty acids was lower than that of unsaturated fatty acids. The ADC of monoenoic fatty acids was lowest in groups fed PF diet (88.0±1.3%) and highest with FxO diet (96.1±0.3%), followed by groups fed CO and SO diets. Polyunsaturated fatty acids were better digested from the FxO diet and the PF diet showed the lowest values. The FxO and SO diets, which contained higher amounts of n-6 fatty acids, also showed relatively high ADC values of these fatty acids. These results suggest that vegetable oils are well utilized by juvenile halibut, and particularly FxO shows good potential to replace HO in commercial halibut feeds.

Fish Oil Supplementation Lowers C‐Reactive Protein Levels Independent of Triglyceride Reduction in Patients With End‐Stage Renal Disease

Inflammation has been identified as a marker for cardiovascular disease. The purpose of this study is to examine the effects of fish oil fatty acid supplementation on C-reactive protein (CRP) levels. The study uses a double-blind, permuted-randomized, and placebo-controlled experimental protocol. Patients are randomly placed into a fish oil group or a control group. Thirty-three patients in the experimental and control groups ingest 2 soft-gel pills (1 g each) of fish oil supplements containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) or placebo at each meal. Patients follow the supplementation protocol for 6 months. Analysis of variance (ANOVA) is used to measure pretest and posttest differences in the variable of interest. A Kolmogorov-Smirnov test for normality is used to test whether CRP levels are normally distributed. The Kolmogorov-Smirnov test for CRP finds a P value of .273 (KS = .997), revealing that the distribution is normal. ANOVA reveals no statistically significant difference between groups at baseline for CRP (F = 4.118, P = .053). ANOVA reveals a significant main effect (F = 4.29, P = .048) for CRP, with the EPA/DHA group having a significant change in values from pretest (16 mg/dL, standard deviation [SD] = 13.80) to posttest (10.22 mg/dL, SD = 7.87). The placebo group's CRP levels do not change significantly from pretest (13.37, standard deviation [SD] = 7.94) to posttest (13.67, SD = 7.07). An observed power calculation using Cohen's D with a computed alpha of .05 is .588. The study demonstrates that consuming 960 mg/d of EPA and 600 mg/d of DHA can lower CRP.

Marine phospholipids—a promising new dietary approach to tumor-associated weight loss

Advanced tumor disease very often evokes excessive loss of body weight. Among others, fish oil or marine fatty acid ethyl esters were investigated for treatment of cancer cachexia with controversial results. In this study, a new formulation of marine fatty acids was investigated, the marine phospholipids, with more than 50% of phospholipid-bound fatty acids being eicosapentaenoic and docosahexaenoic acid. Thirty-one tumor patients with various tumor entities suffering from weight loss were asked to take marine phospholipids (1.5 g/day) as softgel capsules for a period of 6 weeks. Compliance, body weight, appetite, and quality of life as well as the fatty acid profile in plasma and blood cells were monitored; 17 patients could be analyzed. Marine phospholipids were very well accepted; low-dose supplementation resulted in a significant increase of eicosapentaenoic and docosahexaenoic acid in plasma phospholipids; therefore, significantly reducing the n-6 to n-3 fatty acid ratio. A stabilization of body weight was achieved (median weight change of +0.6% after 6 weeks), while appetite and quality of life improved. These promising first results encourage further investigation of marine phospholipids in cancer care.

Omega-3 fatty acids alter soluble markers of endothelial function in coronary heart disease patients.

Several studies have indicated that omega-3 poly-unsaturated fatty acids in fish oil have protective effects on cardiovascular disease by reducing vascular endothelial inflammation in atherosclerosis. In a recent study, supplementation of patients with fish oil following coronary angioplasty elevated levels of lipid peroxides and two adhesion molecules in plasma suggesting a proinflammatory action of fish oil. However, decreases in several plasma markers of endothelial hemostatic activity indicated a healthier and better vasculature associated with fish oil supplementation.

The Response to Fish Oil in Patients with Heart Disease Depends on the Predominant Arrhythmia Mechanism

Dear sir, We have read with interest the paper by Nodari et al [1] and the editorial by Dr. Raitt [2] on fish oil fatty acids and arrhythmic risk in heart failure patients caused by idiopathic dilated cardiomyopathy. In both publications, the mechanism by which fish oils may be both pro- and antiarrhythmic are mentioned but remain un-clarified. The heterogeneous response to fish oil in patients with heart disease may be explained by the arrhythmia mechanism. The GISSI Trial showed that long-term supplementation with fish oil reduced cardiovascular mortality following a myocardial infarction [3]. This could be attributed to a 45% reduction in sudden death, suggesting a direct antiarrhythmic effect of fish oil in these patients [4]. Subsequently, the effect of fish oil on arrhythmias was studied in patients with implanted cardiac defibrillators that suffered from a variety of cardiac pathologies [5–7]. The results were controversial; proarrhythmic and antiarrhythmic effects as well as absence of effects were documented. The recent meta-analysis by Jenkins and co-workers [8] confirmed heterogeneous outcomes in fish oil trials and concludes that fish oils need to be prescribed with caution. The question remains: Why is the response to fish oil heterogeneous? One possibility is that the diverse patient populations have different arrhythmogenic substrates (heart failure, acute ischemia, infarcted myocardium). Circulating and membrane-bound fish oils shorten the cardiac action potential duration by modulating several ion channels (for review see [9]). Shortening of the action potential, as seen in fish oil fed pigs [10], is proarrhythmic during acute myocardial ischemia [11]. Blockade of the cardiac sodium channel by fish oil may slow conduction, and favor reentrant activation. In contrast, the cardiac action potential is prolonged during heart failure, leading to triggered arrhythmias [12]. Action potential or repolarization time shortening in this setting is antiarrhythmic. In the patients with idiopathic dilated cardiomyopathy that were studied by Nodari and coworkers [1], the predominant arrhythmia mechanism likely is triggered activity. These triggered arrhythmias are inhibited by fish oil in isolated myocytes of patients with end-stage heart failure as a result of cardiac action potential shortening in combination with lower diastolic calcium levels and a reduced response to β-adrenergic stimulation [13]. Fish oils also affect heart rate, lipoprotein levels, inflammatory pathways and hypertrophy and thus also indirectly may determine whether the heart develops arrhythmia. Altogether this leads to a complex situation; fish oil is antiarrhythmic under conditions of heart failure, and proarrhythmic under condition of acute myocardial ischemia. Patients, especially those with heart disease, may have both types of arrhythmia mechanisms. This makes the outcome of dietary supplementation with fish oil difficult to predict. The paper of Nodari [1] nicely demonstrates that the effect of fish oil can be best studied in a well defined patient population. We are of the opinion that fish oil supplementation can be safely administered in these patients with idiopathic dilated cardiomyopathy. Whether or not this is the case for other heart disease patients depends on the main arrhythmia mechanism.

Comprehensive supercritical fluid chromatography × reversed phase liquid chromatography for the analysis of the fatty acids in fish oil

The separation of the phenacyl esters of the fatty acids originating from a fish oil extract by means of a comprehensive analysis using silver-ion (SI) supercritical fluid chromatography (SFC) and reversed phase liquid chromatography (RP-LC) in the first and second dimensions, respectively, is described. The combination ensured a high orthogonality and peak capacity, particularly when compared to the comprehensive RP-LC × 2RP-LC separation achieved by using a configuration with two columns in parallel in the second dimension. The construction of the SI-SFC × RP-LC interface consists of two two-position/ten-port switching valves, of which one is equipped with two loops packed with octadecyl silica (ODS) particles. Compared to the SFC × RP-LC configuration described in an earlier publication, the peak capacity in the second dimension was increased. Water was not only added as make-up fluid to the SFC effluent to ensure analyte focusing, but also as rinsing medium of the loops prior to the transfer of the fractions to the second dimension. In the SFC dimension, high efficiency and loadability were obtained by coupling two wide-bore columns (4.6 mm ID) in series. Evaporative light scattering (ELSD) and ultraviolet (UV) detection with standard and high-pressure flow cells were evaluated in terms of data acquisition speed and suppression of signal interferences originating from the supercritical carbon dioxide (CO 2) expansion.

CARDIOPROTECTIVE EFFECT OF FISH OIL ON ISOPROTERENOL‐INDUCED MYOCARDIAL INFARCTION IN RATS

ABSTRACT Epidemiological studies indicate a low incidence of cardiac diseases in populations that consume large amounts of seafood. This effect is attributed to the presence of n‐3 polyunsaturated fatty acids in fish oil. In this study, the protective effect of fish oil against isoproterenol induced changes in histopathology; hematology and lysosomal membrane integrity were evaluated in male wistar rats. The rats were fed fish oil for 45 days prior to isoproterenol treatment. The animals were sacrificed by cervical decapitation method 12 h after the second injection of isoproterenol hydrochloride. The results suggest that pretreatment with fish oil prevented isoproterenol‐induced hematological changes. Lysosomal membrane integrity was also protected in fish oil pretreated rats, as indicated by significantly lowered activities of lysosomal hydrolases in serum and concomitant increase in their activity in the lysosomal fraction of heart. The histopathology studies further confirmed the cardioprotective effect of fish oil. PRACTICAL APPLICATIONSFish oil consumption offers cardioprotection by its ability to modulate biological membranes. This study demonstrates the ability of fish oil to modulate hematological parameters and maintain lysosomal membrane integrity, thereby offering multifaceted protection to the heart. Hence, fish oils, especially those of marine origin, have excellent potential as cardioprotective agents.

Reduction in Oxidation Index Value of Fish Oils Using Hydrophobic Nonporous Denser Membrane Process

Attempts were made to remove the oxidation products from fish oil with membrane process as an improved refining method. A study was conducted with hexane-diluted fish oils of Engraulis japonicus and Maurolicus japonicus in a batch membrane cell using hydrophobic nonporous denser membrane. Peroxide, anisidine and TOTOX values were reduced by 58-72%, 45-75% and 53-73%, respectively. During the membrane process, fatty acids compositions of both fish oils were not changed. The membrane process has an effect in the removal of oxidation products such as toxicity, off-flavor, and color compounds maintaining the beneficial function arising from polyunsaturated fatty acids of fish oils. In the fish oilhexane systems, when the oil contents of feeds were 25-33%, the oil fluxes were obtained in the range of 1.0-2.0 kg/(m2 h). In addition, preferential permeations of hexane over fish oils through the membrane were observed.

魚油バイオディーゼルに含まれる脂肪酸メチルエステルの酸化挙動および部分水素化処理による酸化安定性の改善

Waste cooking oil contaminated with fish oil has potential uses as a biodiesel fuel feedstock. The changes in properties of fish oil fatty acid methyl ester (FAME) caused by oxidation were first evaluated, and the oxidation stability of fish oil FAME was improved by partial hydrogenation using a noble metal catalyst.Oxidation of fish oil FAME resulted in many decomposition products such as aldehydes, carboxylic acids and ketones, and large amounts of sludge. The oxidation propensity of FAME was proportional to the degree of unsaturation, and polyunsaturated FAMEs with more than 4 double bonds, the main components of fish oil FAME, were almost completely oxidized. Elemental analysis and FT-IR analysis showed that the sludge contained large amounts of oxygen compounds assigned as ketones, esters and carboxylic acids. Gel permeation chromatography (GPC) indicated that the sludge seemed to be formed by polymerization of about ten molecules of FAME, especially polyunsaturated FAME molecules. To improve the oxidation stability of fish oil contaminated biodiesel fuel, partial hydrogenation of fish oil FAME was carried out over Pd-Pt/Yb-USY-Al2O3 catalyst, with the fish oil FAME mixed with rapeseed oil to simulate the waste cooking oil contaminated with fish oil. Unsaturated FAMEs with more than 2 double bonds were selectively hydrogenated to monounsaturated and saturated FAMEs. Hydrogenated mixed FAME did not form any sludge and the oxidation stability was significantly improved compared with the untreated FAME. The oxidation stability of hydrogenated FAME blended with petroleum diesel was almost equivalent to that of petroleum diesel. Reduction of polyunsaturated FAME by partial hydrogenation is effective for improving the oxidation stability as well as suppression of sludge formation.