EPA-rich Oil Research Articles

Optimizing Artemia Enrichment: A Low DHA/High EPA Protocol for Enhanced n-3 LC-HUFA Levels to Support Greater Amberjack (Seriola dumerili) Larval Rearing.

Most commercial products available for Artemia sp. enrichment include high levels of docosahexaenoic acid (DHA) to boost its nutritional value, though with limited success. In this regard, the present study evaluated the alternative utilization of eicosapentaenoic acid (20 : 5n-3; EPA) oils to improve the n-3 long-chain highly unsaturated fatty acid content (n-3 LC-HUFA) in enriched Artemia sp. to feed greater amberjack (Seriola dumerili) larvae. Five experimental emulsions containing increasing levels of EPA from 0.8% to 60% of total fatty acids (TFA) and n-3 LC-HUFA (1.3%-70.6% TFA) were formulated. Each diet was fed to greater amberjack larvae (17-35 days posthatch (dph)) in three replicate 200-L tanks. The dietary EPA supplementation significantly improved larval growth during the feeding trial and survival at 35 dph (P < 0.05). In addition, larval fatty acid profiles showed a positive correlation with dietary EPA. Finally, despite the sum of total skeletal anomalies and column anomalies were not significantly affected by dietary EPA, increasing dietary EPA, and n-3 LC-HUFA tended to reduce the incidence of these types of anomalies in greater amberjack larvae at 35 dph. Based on these results, S. dumerili larvae could be successfully grown with low DHA but high EPA-rich oil enrichment products when n-3 LC-HUFA content in Artemia sp. is maintained in sufficient amounts.

Protective mechanisms of a microbial oil against hypercholesterolemia: evidence from a zebrafish model.

A Western diet elevates the circulating lipoprotein and triglyceride levels which are the major risk factors in cardiovascular disease (CVD) development. Consumption of long-chain omega-3 fatty acids can stall the disease progression. Although these fatty acids can significantly impact the intestine under a hypercholesterolemic condition, the associated changes have not been studied in detail. Therefore, we investigated the alterations in the intestinal transcriptome along with the deviations in the plasma lipids and liver histomorphology of zebrafish offered DHA- and EPA-rich oil. Fish were allocated to 4 dietary treatments: a control group, a high cholesterol group and microbial oil groups with low (3.3%) and high (6.6%) inclusion levels. We quantified the total cholesterol, lipoprotein and triglyceride levels in the plasma. In addition, we assessed the liver histology, intestinal transcriptome and plasma lipidomic profiles of the study groups. The results suggested that higher levels of dietary microbial oil could control the CVD risk factor indices in zebrafish plasma. Furthermore, microbial oil-fed fish had fewer liver vacuoles and higher mRNA levels of genes involved in β-oxidation and HDL maturation. Analyses of the intestine transcriptome revealed that microbial oil supplementation could influence the expression of genes altered by a hypercholesterolemic diet. The plasma lipidomic profiles revealed that the higher level of microbial oil tested could elevate the long-chain poly-unsaturated fatty acid content of triglyceride species and lower the concentration of several lysophosphatidylcholine and diacylglycerol molecules. Our study provides insights into the effectiveness of microbial oil against dyslipidemia in zebrafish.

Eicosapentaenoic acid-rich oil supplementation activates PPAR-γ and delays skin wound healing in type 1 diabetic mice.

Delayed wound healing is a devastating complication of diabetes and supplementation with fish oil, a source of anti-inflammatory omega-3 (ω-3) fatty acids including eicosapentaenoic acid (EPA), seems an appealing treatment strategy. However, some studies have shown that ω-3 fatty acids may have a deleterious effect on skin repair and the effects of oral administration of EPA on wound healing in diabetes are unclear. We used streptozotocin-induced diabetes as a mouse model to investigate the effects of oral administration of an EPA-rich oil on wound closure and quality of new tissue formed. Gas chromatography analysis of serum and skin showed that EPA-rich oil increased the incorporation of ω-3 and decreased ω-6 fatty acids, resulting in reduction of the ω-6/ω-3 ratio. On the tenth day after wounding, EPA increased production of IL-10 by neutrophils in the wound, reduced collagen deposition, and ultimately delayed wound closure and impaired quality of the healed tissue. This effect was PPAR-γ-dependent. EPA and IL-10 reduced collagen production by fibroblasts in vitro. In vivo, topical PPAR-γ-blockade reversed the deleterious effects of EPA on wound closure and on collagen organization in diabetic mice. We also observed a reduction in IL-10 production by neutrophils in diabetic mice treated topically with the PPAR-γ blocker. These results show that oral supplementation with EPA-rich oil impairs skin wound healing in diabetes, acting on inflammatory and non-inflammatory cells.

Sustainable production of eicosapentaenoic acid-rich oil from microalgae: Towards an algal biorefinery.

Utilization of sustainable natural resources such as microalgae has been considered for the production of biofuels, aquaculture feed, high-value bioactives such as omega-3 fatty acids, carotenoids, etc. Eicosapentaenoic acid (EPA) is an omega-3 fatty acid present in fish oil, which is of physiological importance to both humans and fish. Marine microalgae are sustainable sources of lipid rich in EPA, and different species have been explored for the production of EPA as a single product. There has been a rising interest in the concept of a multi-product biorefinery, focusing on the maximum valorization of the algal biomass. Targeting one or more value-added compounds in a biorefinery scenario can improve the commercial viability of low-value products such as triglycerides for biofuel. This approach has been viewed by technologists and experts as a sustainable and economically feasible possibility for the large-scale production of microalgae for its potential applications in biodiesel and jet fuel production, nutraceuticals, animal and aquaculture feeds, etc. In this review paper, we describe the recent developments in the production of high-value EPA-rich oil from microalgae, emphasizing the upstream and downstream bioprocess techniques, and the advantages of considering an EPA-rich oil-based biorefinery.

Supplementation with oil rich in eicosapentaenoic acid, but not in docosahexaenoic acid, improves global cognitive function in healthy, young adults: results from randomized controlled trials

ABSTRACTBackgroundEvidence regarding the effects of the omega-3 (ɷ-3) PUFAs (n–3 PUFAs) DHA and EPA on cognition is lacking.ObjectivesWe investigated whether supplementation with oils rich in EPA or DHA improves cognition, prefrontal cortex (PFC) hemoglobin (Hb) oxygenation, and memory consolidation.MethodsHealthy adults (n = 310; age range: 25–49 y) completed a 26-wk randomized controlled trial in which they consumed either 900 mg DHA/d and 270 mg EPA/d (DHA-rich oil), 360 mg DHA/d and 900 mg EPA/d (EPA-rich oil), or 3000 mg/d refined olive oil (placebo). Cognitive performance and memory consolidation were assessed via computerized cognitive test battery. PFC Hb oxygenation was measured using near infrared spectroscopy (NIRS).ResultsBoth global accuracy and speed improved with EPA-rich oil compared with placebo and DHA-rich oil [EPA vs. placebo accuracy: estimated marginal mean (EMM) = 0.17 (95% CI: 0.09, 0.24) vs. EMM = 0.03 (95% CI = −0.04, 0.11); P = 0.044; EPA vs. placebo speed: EMM = −0.15 (95% CI: −0.22, −0.07) vs. EMM = 0.03 (95% CI: −0.05, 0.10); P = 0.003]. Accuracy of memory was improved with EPA compared with DHA [EMM = 0.66 (95% CI: 0.26, 1.06) vs. EMM = −0.08 (95% CI: −0.49, 0.33); P = 0.034]. Both EPA- and DHA-rich oils showed trends towards reduced PFC oxygenated Hb (oxy-Hb) compared with placebo [placebo: EMM = 27.36 µM (95% CI: 25.73, 28.98); DHA: EMM = 24.62 µM (95% CI: 22.75, 26.48); P = 0.060; EPA: EMM = 24.97 µM (95% CI: 23.35, 26.59); P = 0.082].ConclusionsEPA supplementation improved global cognitive function and was superior to the oil enriched with DHA. Interpreted within a neural efficiency framework, reduced PFC oxygenated Hb suggests that n–3 PUFAs may be associated with increased efficiency.These trials were registered in the clinical trials registry (https://clinicaltrials.gov/) as NCT03158545, NCT03592251, NCT02763514.

Development of a Phaeodactylum tricornutum biorefinery to sustainably produce omega-3 fatty acids and protein

Phaeodactylum tricornutum is a genetically well-studied microalga but commercial production of omega-3 fatty acids and protein had not been established. Here, a biorefinery platform to cost-effectively culture, harvest and process this diatom has been developed. Using a sea salt substitute supplemented with magnesium enabled low-cost land-based cultivation, reaching biomass yields of 0.17 g L−1day−1 and 340 g m−2day−1 in free-standing outdoor photobioreactors. pH-induced auto-flocculation in bioreactors or open ponds followed by solar drying was most cost-effective to harvest dry biomass. Lipids extracted by organic solvents accounted for 27.3% per dry biomass. Ethanol was the safest and most suitable option for a biorefinery yielding 92% of extractable omega-3 eicosapentaenoic acid (EPA) and 40.9% of protein in the defatted biomass. Using Central Composite Design, optimized alkaline extraction recovered 60.4% of total protein. A cost comparison to Nannochloropsis microalgae showed that EPA-rich oil and protein for human consumption are the most viable products with potentially lower EPA production costs. This study demonstrates that land-based P. tricornutum cultivation can provide a sustainable source of omega-3 fatty acid without putting pressures on marine bioresources.

Room Temperature Nanoencapsulation of Bioactive Eicosapentaenoic Acid Rich Oil within Whey Protein Microparticles.

In this study, emulsion electrospraying assisted by pressurized gas (EAPG) has been performed for the first time to entrap ca. 760 nm droplets of the bioactive eicosapentaenoic acid (EPA)-rich oil into whey protein concentrate (WPC) at room temperature. The submicron droplets of EPA oil were encapsulated within WPC spherical microparticles, with sizes around 5 µm. The EPA oil did not oxidize in the course of the encapsulation performed at 25 °C and in the presence of air, as corroborated by the peroxide value measurements. Attenuated Total Reflection—Fourier Transform Infrared spectroscopy and oxygen consumption tests confirmed that the encapsulated EPA-rich oil showed increased oxidative stability in comparison with the free oil during an accelerated oxidation test under ultraviolet light. Moreover, the encapsulated EPA-rich oil showed increased thermal stability in comparison with the free oil, as measured by oxidative thermogravimetric analysis. The encapsulated EPA-rich oil showed a somewhat reduced organoleptic impact in contrast with the neat EPA oil using rehydrated powdered milk as a reference. Finally, the oxidative stability by thermogravimetric analysis and organoleptic impact of mixtures of EPA and docosahexaenoic acid (DHA)-loaded microparticles was also studied, suggesting an overall reduced organoleptic impact compared to pure EPA. The results here suggest that it is possible to encapsulate 80% polyunsaturated fatty acids (PUFAs)-enriched oils by emulsion EAPG technology at room temperature, which could be used to produce personalized nutraceuticals or pharmaceuticals alone or in combination with other microparticles encapsulating different PUFAs to obtain different targeted health and organoleptic benefits.

Differential Effects of DHA- and EPA-Rich Oils on Sleep in Healthy Young Adults: A Randomized Controlled Trial.

Emerging evidence suggests that adequate intake of omega-3 polyunsaturated fatty acids (n-3 PUFAs), which include docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), might be associated with better sleep quality. N-3 PUFAs, which must be acquired from dietary sources, are typically consumed at suboptimal levels in Western diets. Therefore, the current placebo-controlled, double-blind, randomized trial, investigated the effects of an oil rich in either DHA or EPA on sleep quality in healthy adults who habitually consumed low amounts of oily fish. Eighty-four participants aged 25–49 years completed the 26-week intervention trial. Compared to placebo, improvements in actigraphy sleep efficiency (p = 0.030) and latency (p = 0.026) were observed following the DHA-rich oil. However, these participants also reported feeling less energetic compared to the placebo (p = 0.041), and less rested (p = 0.017), and there was a trend towards feeling less ready to perform (p = 0.075) than those given EPA-rich oil. A trend towards improved sleep efficiency was identified in the EPA-rich group compared to placebo (p = 0.087), along with a significant decrease in both total time in bed (p = 0.032) and total sleep time (p = 0.019) compared to the DHA-rich oil. No significant effects of either treatment were identified for urinary excretion of the major melatonin metabolite 6-sulfatoxymelatonin. This study was the first to demonstrate some positive effects of dietary supplementation with n-3 PUFAs in healthy adult normal sleepers, and provides novel evidence showing the differential effects of n-3 PUFA supplements rich in either DHA or EPA. Further investigation into the mechanisms underpinning these observations including the effects of n-3 PUFAs on sleep architecture are required.

Oral administration of EPA-rich oil impairs collagen reorganization due to elevated production of IL-10 during skin wound healing in mice

Wound healing is an essential process for organism survival. Some fatty acids have been described as modulators of wound healing. However, the role of omega-3 fatty acids is unclear. In the present work, we investigate the effects of oral administration of eicosapentaenoic acid (EPA)-rich oil on wound healing in mice. After 4 weeks of EPA-rich oil supplementation (2 g/kg of body weight), mice had increased serum concentrations of EPA (20:5ω-3) (6-fold) and docosahexaenoic acid (DHA; 22:6ω-3) (33%) in relation to control mice. Omega-3 fatty acids were also incorporated into skin in the EPA fed mice. The wound healing process was delayed at the 3rd and 7th days after wounding in mice that received EPA-rich oil when compared to control mice but there was no effect on the total time required for wound closure. Collagen reorganization, that impacts the quality of the wound tissue, was impaired after EPA-rich oil supplementation. These effects were associated with an increase of M2 macrophages (twice in relation to control animals) and interleukin-10 (IL-10) concentrations in tissue in the initial stages of wound healing. In the absence of IL-10 (IL-10−/− mice), wound closure and organization of collagen were normalized even when EPA was fed, supporting that the deleterious effects of EPA-rich oil supplementation were due to the excessive production of IL-10. In conclusion, oral administration of EPA-rich oil impairs the quality of wound healing without affecting the wound closure time likely due to an elevation of the anti-inflammatory cytokine IL-10.

Differential effects of EPA versus DHA on postprandial vascular function and the plasma oxylipin profile in men

Our objective was to investigate the impact of EPA versus DHA on arterial stiffness and reactivity and underlying mechanisms (with a focus on plasma oxylipins) in the postprandial state. In a three-arm crossover acute test meal trial, men (n = 26, 35–55 years) at increased CVD risk received a high-fat (42.4 g) test meal providing 4.16 g of EPA or DHA or control oil in random order. At 0 h and 4 h, blood samples were collected to quantify plasma fatty acids, long chain n-3 PUFA-derived oxylipins, nitrite and hydrogen sulfide, and serum lipids and glucose. Vascular function was assessed using blood pressure, reactive hyperemia index, pulse wave velocity, and augmentation index (AIx). The DHA-rich oil significantly reduced AIx by 13% (P = 0.047) with the decrease following EPA-rich oil intervention not reaching statistical significance. Both interventions increased EPA- and DHA-derived oxylipins in the acute postprandial state, with an (1.3-fold) increase in 19,20-dihydroxydocosapentaenoic acid evident after DHA intervention (P < 0.001). In conclusion, a single dose of DHA significantly improved postprandial arterial stiffness as assessed by AIx, which if sustained would be associated with a significant decrease in CVD risk. The observed increases in oxylipins provide a mechanistic insight into the AIx effect.

Recent developments in the commercial production of DHA and EPA rich oils from micro-algae

The regular intake of marine omega 3’s DHA and EPA has been scientifically established as providing a wide range of health benefits. This paper reviews recent developments in the commercial production of DHA and EPA rich oils from micro-algae. The selection of suitable micro-algae species is discussed. The complexities of producing algal oil rich in marine omega 3’s is examined in terms of both upstream and downstream production.

The bioaccessibility of eicosapentaenoic acid was higher from phospholipid food products than from mono- and triacylglycerol food products in a dynamic gastrointestinal model.

The bioaccessibility of eicosapentaenoic acid (EPA) in the forms of monoacylglycerol (EPA-MAG), triacylglycerol (EPA-TAG), and phospholipid (EPA-PL) during gastrointestinal passage was compared in this study using a dynamic gastrointestinal model (TIM system). The TIM system simulated the average upper gastrointestinal tract conditions of healthy human adults after intake of a meal (fed state conditions). In this study, the three EPA-rich oils were separately homogenized with full fat milk to obtain oil-in-water emulsions. Plain yogurt was added into the mixture at an emulsion/yogurt ratio of 4:1 (w/w) as the food matrix of the test products. The results show that the test meals containing EPA-PL left the stomach compartment most efficiently in comparison with the gastric emptying of EPA-MAG and EPA-TAG. The PLs also showed a significantly (P < 0.05) higher bioaccessibility of EPA (75–80%) in comparison with MAG (30%) and TAG (38%). The better gastric emptying of EPA-PL was likely related to the more stable emulsion of EPA-PL in the test meal. EPA-PL was delivered within the meal matrix into the duodenum instead of floating on the top of the test meal matrix. EPA-MAG had the highest amount of EPA that did not leave the stomach (68% of the test meal). The results from this work indicate that EPA-PL is a more effective form of EPA for a higher lipid bioaccessibility than MAG and TAG under the test conditions.

Comparative study of gastrointestinal absorption of EPA & DHA rich fish oil from nano and conventional emulsion formulation in rats

In our present study, we worked on the preparation of oil-in-water nanoemulsion (NE) and conventional emulsion (CE) with EPA and DHA rich fish lipid oil and comparison of their in vivo intestinal absorption in the single-pass perfusion rat model. Oil-in-Water (O/W) NE and CE using fish lipid oil and Tween 20 and Span 80 as emulsifier/ coemulsifier combination have been successfully prepared by high energy emulsification techniques- high speed homogenization and ultrasonication. The cumulative average droplet diameter of the NEs has been found to be ranged between 78.96nm and 94.20nm, with PdI ranging from 0.174 to 0.344, whereas the average droplet diameter of the CEs is 1.58±0.31μm. The viscosity and refractive index of the emulsions have been determined. In situ absorption efficiency of the emulsions is measured in laboratory acclimatized adult Sprague–Dawley rats. A comparative study of lipid absorption from NE and CE of similar dilution level, in cannulated small intestine of rats, at time gradient, has been done. Subsequent analysis (e.g. percent volume absorption, percent lipid absorption) have shown that the NE has significantly enhanced the absorption of lipids from the emulsion system, in the small intestine of the rats. This finding about absorption of lipid nanoformulations could be useful for designing lipid-based enteral nutrition therapy for the lipid mal-nutrient patients in future.

Regulation of inflammatory and lipid metabolism genes by eicosapentaenoic acid-rich oil

Omega-3-PUFAs, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), are associated with prevention of various aspects of metabolic syndrome. In the present studies, the effects of oil rich in EPA on gene expression and activation of nuclear receptors was examined and compared with other ω3-PUFAs. The EPA-rich oil (EO) altered the expression of FA metabolism genes in THP-1 cells, including stearoyl CoA desaturase (SCD) and FA desaturase-1 and -2 (FASDS1 and -2). Other ω3-PUFAs resulted in a similar gene expression response for a subset of genes involved in lipid metabolism and inflammation. In reporter assays, EO activated human peroxisome proliferator-activated receptor α (PPARα) and PPARβ/γ with minimal effects on PPARγ, liver X receptor, retinoid X receptor, farnesoid X receptor, and retinoid acid receptor γ (RARγ); these effects were similar to that observed for purified EPA. When serum from a 6 week clinical intervention with dietary supplements containing olive oil (control), DHA, or two levels of EPA were applied to THP-1 cells, the expression of SCD and FADS2 decreased in the cells treated with serum from the ω3-PUFA-supplemented individuals. Taken together, these studies indicate regulation of gene expression by EO that is consistent with treating aspects of dyslipidemia and inflammation.

Regulation of inflammatory and lipid metabolism genes by eicosapentaenoic acid‐rich oil

Omega‐3 polyunsaturated fatty acids (ω3‐PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are associated with prevention of various aspects of metabolic syndrome. In the present studies, the effects of oil rich in EPA on gene expression and activation of nuclear receptors was examined and compared to other ω3‐PUFAs. The EPA‐rich oil (EO) altered the expression of fatty acid metabolism genes in THP‐1 cells including stearoyl CoA desaturase (SCD) and fatty acid desaturase 1 and 2 (FASDS1 and 2). Other ω3‐PUFAs resulted in a similar gene expression response for a subset of genes involved in lipid metabolism and inflammation. In reporter assays, EO activated human PPARα and PPARβ/γ with minimal effects on PPARγ, LXR, RXR, FXR and RARγ; these effects were similar to that observed for purified EPA. When serum from a six week clinical intervention with dietary supplements containing olive oil (control), DHA or two levels of EO were applied to THP‐1 cells, the expression of SCD and FADS2 decreased in the cells treated with serum from the ω3‐PUFA supplemented individuals. Taken together these studies indicate regulation of gene expression by the EPA‐rich oil that is consistent with treating aspects of dyslipidemia and inflammation. (Supported by DuPont Central Research and Development).

Safety assessment of EPA-rich oil produced from yeast: Results of a 90-day subchronic toxicity study

The safety of eicosapentaenoic acid (EPA) oil produced from genetically modified Yarrowia lipolytica yeast was evaluated following 90 days of exposure. Groups of rats received 0 (olive oil), 98, 488, or 976 mg EPA/kg/day, or GRAS fish oil or deionized water by oral gavage. Rats were evaluated for in-life, neurobehavioral, anatomic and clinical pathology parameters. Lower serum cholesterol (total and non-HDL) was observed in Medium and High EPA and fish oil groups. Lower HDL was observed in High EPA and fish oil males, only at early time points. Liver weights were increased in High EPA and Medium EPA (female only) groups with no associated clinical or microscopic pathology findings. Nasal lesions, attributed to oil in the nasal cavity, were observed in High and Medium EPA and fish oil groups. No other effects were attributed to test oil exposure. Exposure to EPA oil for 90 days produced no effects at 98 mg EPA/kg/day and no adverse effects at doses up to 976 mg EPA/kg/day. The safety profile of EPA oil was comparable to that of GRAS fish oil. These results support the use of EPA oil produced from yeast as a safe source for use in dietary supplements.

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.

Contribution of apolipoprotein E genotype and docosahexaenoic acid to the LDL-cholesterol response to fish oil

ObjectivesTo investigate the impact of apolipoprotein E (apoE) genotype on the response of the plasma lipoprotein profile to eicosapentaenoic acid (EPA) versus docosahexaenoic acid (DHA) intervention in humans. Methods and results38 healthy normolipidaemic males, prospectively recruited on the basis of apoE genotype (n=20 E3/E3 and n=18 E3/E4), completed a double-blind placebo-controlled cross-over trial, consisting of 3×4 week intervention arms of either control oil, EPA-rich oil (ERO, 3.3g EPA/day) or DHA-rich oil (DRO, 3.7g DHA/day) in random order, separated by 10 week wash-out periods. A significant genotype-independent 28% and 19% reduction in plasma triglycerides in response to ERO and DRO was observed. For total cholesterol (TC), no significant treatment effects were evident; however a significant genotype by treatment interaction emerged (P=0.045), with a differential response to ERO and DRO in E4 carriers. Although the genotype×treatment interaction for LDL-cholesterol (P=0.089) did not reach significance, within DRO treatment analysis indicated a 10% increase in LDL (P=0.029) in E4 carriers with a non-significant 4% reduction in E3/E3 individuals. A genotype-independent increase in LDL mass was observed following DRO intervention (P=0.018). Competitive uptake studies in HepG2 cells using plasma very low density lipoproteins (VLDL) from the human trial, indicated that following DRO treatment, VLDL2 fractions obtained from E3/E4 individuals resulted in a significant 32% (P=0.002) reduction in LDL uptake relative to the control. ConclusionsHigh dose DHA supplementation is associated with increases in total cholesterol in E4 carriers, which appears to be due to an increase in LDL-C and may in part negate the cardioprotective action of DHA in this population subgroup.

Limited effect of eicosapentaenoic acid on T-lymphocyte and natural killer cell numbers and functions in healthy young males

Objective Greatly increasing the amount of long-chain ω-3 polyunsaturated fatty acids in the diet has been reported in some studies to decrease T-lymphocyte and natural killer functions. However, dose-response relations have not been identified. The objective of this study was to determine the effect of supplementing the diet of young male subjects with different amounts of an oil rich in eicosapentaenoic acid (EPA) on T-lymphocyte proliferation, cytokine production by T lymphocytes, and natural killer cell activity. Methods In a placebo-controlled, double-blind, parallel study, healthy young (18 to 42 y) males were randomized to one of four supplements. These were placebo (no additional ω-3 polyunsaturated fatty acids) or different amounts of an EPA-rich oil that provided 1.35, 2.7, or 4.05 g/d of EPA for 12 wk. Blood samples were taken at baseline and after 12 wk. Results Eicosapentaenoic acid was incorporated in a linear dose-response fashion into mononuclear cell phospholipids. EPA did not alter the proportions of T lymphocytes, helper T lymphocytes, cytotoxic T lymphocytes, B lymphocytes, or natural killer cells in the bloodstream. T-lymphocyte proliferation in response to concanavalin A and the production of the cytokines interleukin-2, interferon-γ, and interleukin-10 were not affected by the different treatments. However, interleukin-4 production was increased with increasing intake of EPA. Natural killer cell activity was little affected by the treatments, although there was a trend for EPA to increase activity at a low effector-to-target cell ratio. Conclusion T-lymphocyte and natural killer cell numbers and function in healthy young males are little affected by supplemental EPA intakes up to 4 g/d.

Production of structured lipids by acidolysis of an EPA-enriched fish oil and caprylic acid in a packed bed reactor: analysis of three different operation modes.

Structured triacylglycerols (ST) enriched in eicosapentaenoic acid (EPA) in position 2 of the triacylglycerol (TAG) backbone were synthesized by acidolysis of a commercially available EPA-rich oil (EPAX4510, 40% EPA) and caprylic acid (CA), catalyzed by the 1,3-specific immobilized lipase Lipozyme IM. The reaction was carried out in a packed bed reactor (PBR) operating in two ways: (1) by recirculating the reaction mixture from the exit of the bed to the substrate reservoir (discontinuous mode) and (2) in continuous mode, directing the product mixture leaving the PBR to a product reservoir. By operating in these two ways and using a simple kinetic model, representative values for the apparent kinetic constants (kX) for each fatty acid (native, Li or odd, M) were obtained. The kinetic model assumes that the rate of incorporation of a fatty acid into TAG per amount of enzyme, rX (mole/(h g lipase)) is proportional to the extent of the deviation from the equilibrium for each fatty acid (i.e., the difference of concentration between the fatty acid in the triacylglycerol and the concentration of the same fatty acid in the triacylglycerol once the equilibrium of the acidolysis reaction is reached). The model allows comparing the two operating modes through the processing intensity, defined as mLt/(V[TG]0) and mL/(q[TG]0), for the discontinuous and continuous operation modes, respectively. In discontinuous mode, ST with 59.5% CA and 9.6% EPA were obtained. In contrast, a ST with 51% CA and 19.6% EPA were obtained when using the continuous operation mode. To enhance the CA incorporation when operating in continuous mode, a two-step acidolysis reaction was performed (third operation mode). This continuous two-step process yields a ST with a 64% CA and a 15% EPA. Finally, after purifying the above ST in a preparative silica gel column, impregnated with boric acid, a ST with 66.9% CA and 19.6% EPA was obtained. The analysis by reverse phase and Ag+ liquid chromatography of the EPA-enriched ST demonstrated that the CA was placed in positions 1 and 3 and the EPA was occupying position 2 of the final ST.