Incorporation and washout of orally administered n-3 fatty acid ethyl esters in different plasma lipid fractions

Pharmacokinetic Interaction between Atorvastatin and Omega-3 Fatty Acid in Healthy Volunteers

The interaction between statins and omega-3 fatty acids remains controversial. The aim of this phase 1 trial was to evaluate the pharmacokinetics of drug-drug interaction between atorvastatin and omega-3 fatty acids. Treatments were once-daily oral administrations of omega-3 (4 g), atorvastatin (40 mg), and both for 14 days, 7 days, and 14 days, respectively, with washout periods. The concentrations of atorvastatin, 2-OH-atorvastatin, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) were determined with LC-MS/MS. Parameters of DHA and EPA were analyzed after baseline correction. A total of 37 subjects completed the study without any major violations. The geometric mean ratios (GMRs) and 90% confidence intervals (CIs) of the co-administration of a single drug for the area under the concentration–time curve during the dosing interval at steady state of atorvastatin, 2-OH-atorvastatin, DHA, and EPA were 1.042 (0.971–1.118), 1.185 (1.113–1.262), 0.157 (0.091–0.271), and 0.557 (0.396–0.784), respectively. The GMRs (90% Cis) for the co-administration at steady state of atorvastatin, 2-OH-atorvastatin, DHA, and EPA were 1.150 (0.990–1.335), 1.301 (1.2707–1.1401), 0.320 (0.243–0.422), and 0.589 (0.487–0.712), respectively. The 90% CIs for most primary endpoints were outside the range of typical bioequivalence, indicating a pharmacokinetic interaction between atorvastatin and omega-3.

Associations Between Preconception Plasma Fatty Acids and Pregnancy Outcomes

BACKGROUND

Although fatty acids are involved in critical reproductive processes, the relationship between specific fatty acids and fertility is uncertain. We investigated the relationship between preconception plasma fatty acids and pregnancy outcomes.

METHODS

We included 1,228 women attempting pregnancy with one to two previous pregnancy losses from the EAGeR trial (2007-2011). Plasma fatty acids were measured at baseline. We used log-binomial regression to assess associations between fatty acids and pregnancy, pregnancy loss, and live birth, adjusting for age, race, smoking, BMI, physical activity, income, parity, treatment arm, and cholesterol.

RESULTS

Although total saturated fatty acids (SFAs) were not associated with pregnancy outcomes, 14:0 (myristic acid; relative risk [RR] = 1.10, 95% confidence interval [CI] = 1.02, 1.19, per 0.1% increase) and 20:0 (arachidic acid; RR = 1.05, 95% CI = 1.01, 1.08, per 0.1% increase) were positively associated with live birth. Findings suggested a positive association between total monounsaturated fatty acids (MUFAs) and pregnancy and live birth and an inverse association with loss. Total polyunsaturated fatty acids (PUFAs) were associated with lower probability of pregnancy (RR = 0.97, 95% CI = 0.95, 1.00) and live birth (RR = 0.96, 95% CI = 0.94, 0.99), and increased risk of loss (RR = 1.10, 95% CI = 1.00, 1.20), per 1% increase. Trans fatty acids and n-3 fatty acids were not associated with pregnancy outcomes.

CONCLUSIONS

Preconception total plasma MUFAs were positively associated with pregnancy and live birth. PUFAs were inversely associated with pregnancy outcomes. Specific SFAs were associated with a higher probability of live birth. Our results suggest that fatty acids may influence pregnancy outcomes.

Different metabolism of EPA, DPA and DHA in humans: A double-blind cross-over study

This study aimed to compare eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) incorporated into red blood cells (RBC) phospholipids (PL), plasma PL, plasma triglyceride (TAG), and plasma cholesteryl ester (CE) fractions, and the metabolomics profiles in a double-blind cross-over study. Twelve female healthy subjects randomly consumed 1 g per day for 6 days of pure EPA, DPA, or DHA. The placebo treatment was olive oil. The fasting venous blood was taken at days 0, 3 and 6, and the RBC PL and plasma lipid fractions were separated for fatty acid determination using thin layer chromatography followed by gas chromatography. Plasma metabolites were analyzed by UHPLC-Q-Exactive Orbitrap/MS. Supplemental EPA significantly increased the concentrations of EPA in RBC PL (days 3 and 6). For subjects consuming the DPA supplement, the concentrations of both DPA and EPA were significantly increased in RBC PL over a 6-day period, respectively. For plasma PL fraction, EPA and DPA supplementation significantly increased the concentrations of EPA and DPA at both days 3 and 6, respectively. Supplemental DHA significantly increased the concentrations of DHA in plasma PL at day 6. For plasma TAG fraction, supplementation with EPA and DPA significantly increased the concentrations of EPA and DPA at both days 3 and 6, respectively. After DHA supplementation, significant increases in the concentrations of DHA were found relative to baseline at both days 3 and 6. For plasma CE fraction, EPA supplementation significantly increased the concentrations of EPA (days 3 and 6) and DPA (days 6), respectively. Supplemental DPA significantly increased the concentrations of EPA at day 6. Meanwhile, the concentrations of DHA were significantly increased over a 6-day period of intervention after subjects consuming the DHA supplements. There were a total of 922 plasma metabolites identified using metabolomics analyses. Supplementation with DPA and DHA significantly increased the levels of sphingosine 1-phosphate (P _{for DPA} = 0.025, P _{for DHA} = 0.029) and 15-deoxy-Δ12,14-prostaglandin A1 (P _{for DPA} = 0.034; P _{for DHA} = 0.021) in comparison with olive oil group. Additionally, supplementation with EPA (P = 0.007) and DHA (P = 0.005) significantly reduced the levels of linoleyl carnitine, compared with olive oil group. This study shows that DPA might act as a reservoir of n-3 LCP incorporated into blood lipid fractions, metabolized into DHA, and retro-converted back to EPA. Metabolomics analyses indicate that supplemental EPA, DPA and DHA have shared and differentiated metabolites. The differences of these metabolic biomarkers should be investigated in additional studies.

Pharmacokinetics of omega-3 fatty acids in patients with severe sepsis compared with healthy volunteers: A prospective cohort study

BACKGROUND

Pharmacokinetics (PK) of pharmaceuticals and pharmaconutrients are poorly understood in critically ill patients, and dosing is often based on healthy subject data. This might be particularly problematic with enteral medications due to metabolic abnormalities and impaired gastrointestinal tract absorption common in critically ill patients. Utilizing enteral fish oil, this study was undertaken to better understand and define PK of enteral omega-3 fatty acids (eicospentaenoic acid [EPA] and docosahexaenoic acid [DHA]) in critically ill patients with severe sepsis.

MATERIALS AND METHODS

Healthy volunteers (n = 15) and mechanically ventilated (MV) adults with severe sepsis (n = 10) were recruited and received 9.75 g EPA and 6.75 g DHA daily in two divided enteral doses of fish oil for 7 days. Volunteers continued their normal diet without other sources of fish oil, and sepsis patients received standard enteral feeding. Blood was collected at frequent intervals during the 14-day study period. Peripheral blood mononuclear cells (PMBCs) and neutrophils were isolated and analyzed for membrane fatty acid (FA) content. Mixed linear models and t-tests were used to analyze changes in FA levels over time and FA levels at individual time points, respectively. PK parameters were obtained based on single compartment models of EPA and DHA kinetics.

RESULTS

Healthy volunteers were 41.1 ± 10.3 years; 67% were women. In patients with severe sepsis (55.6 ± 13.4 years, 50% women), acute physiologic and chronic health evaluation (APACHE) II score was 27.2 ± 8.8 at ICU admission and median MV duration was 10.5 days. Serum EPA and DHA were significantly lower in sepsis vs. healthy subjects over time. PBMC EPA concentrations were generally not different between groups over time, while PBMC DHA was higher in sepsis patients. Neutrophil EPA and DHA concentrations were similar between groups. The half-life of EPA in serum and neutrophils was significantly shorter in sepsis patients, whereas other half-life parameters did not vary significantly between healthy volunteers and sepsis patients.

CONCLUSIONS

While incorporation of n-3 FAs into PBMC and neutrophil membranes was relatively similar between healthy volunteers and sepsis patients receiving identical high doses of fish oil for one week, serum EPA and DHA were significantly lower in sepsis patients. These findings imply that serum concentrations and EPA and DHA may not be the dominant driver of leukocyte membrane incorporation of EPA and DHA. Furthermore, lower serum EPA and DHA concentrations suggest that either these n-3 FAs were being metabolized rapidly in sepsis patients or that absorption of enteral medications and pharmaconutrients, including fish oil, may be impaired in sepsis patients. If enteral absorption is impaired, doses of enteral medications administered to critically ill patients may be suboptimal.

Enhancing Omega-3 Long-Chain Polyunsaturated Fatty Acid Content of Dairy-Derived Foods for Human Consumption

Omega-3 polyunsaturated fatty acids (n-3 PUFA) are termed essential fatty acids because they cannot be synthesized de novo by humans due to the lack of delta-12 and delta-15 desaturase enzymes and must therefore be acquired from the diet. n-3 PUFA include α-linolenic acid (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), docosahexaenoic (DHA, 22:6n-3), and the less recognized docosapentaenoic acid (DPA, 22:5n-3). The three long-chain (≥C20) n-3 PUFA (n-3 LC-PUFA), EPA, DHA, and DPA play an important role in human health by reducing the risk of chronic diseases. Up to the present time, seafood, and in particular, fish oil-derived products, have been the richest sources of n-3 LC-PUFA. The human diet generally contains insufficient amounts of these essential FA due largely to the low consumption of seafood. This issue provides opportunities to enrich the content of n-3 PUFA in other common food groups. Milk and milk products have traditionally been a major component of human diets, but are also among some of the poorest sources of n-3 PUFA. Consideration of the high consumption of milk and its processed products worldwide and the human health benefits has led to a large number of studies targeting the enhancement of n-3 PUFA content in dairy products. The main objective of this review was to evaluate the major strategies that have been employed to enhance n-3 PUFA content in dairy products and to unravel potential knowledge gaps for further research on this topic. Nutritional manipulation to date has been the main approach for altering milk fatty acids (FA) in ruminants. However, the main challenge is ruminal biohydrogenation in which dietary PUFA are hydrogenated into monounsaturated FA and/or ultimately, saturated FA, due to rumen microbial activities. The inclusion of oil seed and vegetable oil in dairy animal diets significantly elevates ALA content, while the addition of rumen-protected marine-derived supplements is the most effective way to increase the concentration of EPA, DHA, and DPA in dairy products. In our view, the mechanisms of n-3 LC-PUFA biosynthesis pathway from ALA and the biohydrogenation of individual n-3 LC-PUFA in ruminants need to be better elucidated. Identified knowledge gaps regarding the activities of candidate genes regulating the concentrations of n-3 PUFA and the responses of ruminants to specific lipid supplementation regimes are also critical to a greater understanding of nutrition-genetics interactions driving lipid metabolism.

Long-chain omega-3 fatty acids in aneurysmal subarachnoid hemorrhage: A randomized pilot trial of pharmaconutrition

Background:

Functional recovery after aneurysmal subarachnoid hemorrhage (SAH) remains a significant problem. We tested a novel therapeutic approach with long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) to assess the safety and feasibility of an effectiveness trial.

Methods:

We conducted a multicentre, parallel, randomized, open-label pilot trial. Patients admitted within 72 hours after SAH with modified Fisher scale scores of 3 or 4 who were selected for scheduled aneurysm clipping were allocated to receive either n-3 PUFA treatment (parenteral perioperative: 5 days; oral: 8 weeks) plus usual care or usual care alone. Exploratory outcome measures included major postoperative intracranial bleeding complications (PIBCs), cerebral infarction caused by delayed cerebral ischemia, shunt-dependent hydrocephalus, and consent rate. The computed tomography evaluator was blinded to the group assignment.

Results:

Forty-one patients were randomized, but one patient had to be excluded after allocation. Twenty patients remained for intention to treat analysis in each trial arm. No PIBs (95% confidence interval [CI]: 0.00 to 0.16) or other unexpected harm were observed in the intervention group (IG). No patient suspended the intervention due to side effects. There was a trend towards improvements in all benefit-related outcomes in the IG. The overall consent rate was 0.91 (95% CI: 0.78 to 0.96), and there was no consent withdrawal.

Conclusions:

Although the balance between the benefit and harm of the intervention appears highly favourable, further testing on SAH patients is required. We recommend proceeding with amendments in a dose-finding trial to determine the optimal duration of parenteral treatment.

Complete assessment of whole-body n-3 and n-6 PUFA synthesis-secretion kinetics and DHA turnover in a rodent model

Previous assessments of the PUFA biosynthesis pathway have focused on DHA and arachidonic acid synthesis. Here, we determined whole-body synthesis-secretion kinetics for all downstream products of PUFA metabolism, including direct measurements of DHA and n-6 docosapentaenoic acid (DPAn-6, 22:5n-6) turnover, and compared n-6 and n-3 homolog kinetics. We infused labeled α-linolenic acid (ALA, 18:3n-3), linoleic acid (LNA, 18:2n-6), DHA, and DPAn-6 as ²H₅-ALA, ¹³C₁₈-LNA, ¹³C₂₂-DHA, and ¹³C₂₂-DPAn-6. Eight 11-week-old Long Evans rats fed a 10% fat diet were infused with the labeled PUFAs over 3 h, and plasma enrichment of labeled products was measured every 30 min. The DHA synthesis-secretion rate (94 ± 34 nmol/day) did not differ from other PUFA products (range, 21.8 ± 4.3 nmol/day to 408 ± 116 nmol/day). Synthesis-secretion rates of n-6 and n-3 PUFA homologs were similar, except 22:4n-6 and DPAn-6 had lower synthesis rates. However, daily turnover from newly synthesized DHA (0.067 ± 0.023%) was 56-fold to 556-fold slower than all other PUFA turnover and was 130-fold slower than that determined directly from the total plasma unesterified DHA pool. In conclusion, n-6 and n-3 PUFA synthesis-secretion kinetics suggest that differences in turnover, not in synthesis-secretion rates, primarily determine PUFA plasma levels.

Metabolism of uniformly labeled 13C-eicosapentaenoic acid and 13C-arachidonic acid in young and old men

Background: Plasma eicosapentaenoic acid (EPA) and arachidonic acid (AA) concentrations increase with age.Objective: The aim of this study was to evaluate EPA and AA metabolism in young and old men by using uniformly labeled carbon-13 (¹³C) fatty acids.Design: Six young (∼25 y old) and 6 old (∼75 y old) healthy men were recruited. Each participant consumed a single oral dose of 35 mg ¹³C-EPA and its metabolism was followed in the course of 14 d in the plasma and 28 d in the breath. After the washout period of ≥28 d, the same participants consumed a single oral dose of 50 mg ¹³C-AA and its metabolism was followed for 28 d in plasma and breath.Results: There was a time × age interaction for ¹³C-EPA (P_{time × age} = 0.008), and the shape of the postprandial curves was different between young and old men. The ¹³C-EPA plasma half-life was ∼2 d for both young and old men (P = 0.485). The percentage dose recovered of ¹³C-EPA per hour as ¹³CO₂ and the cumulative β-oxidation of ¹³C-EPA did not differ between young and old men. At 7 d, however, old men had a >2.2-fold higher plasma ¹³C-DHA concentration synthesized from ¹³C-EPA compared with young men (P_age = 0.03). ¹³C-AA metabolism was not different between young and old men. The ¹³C-AA plasma half-life was ∼4.4 d in both young and old participants (P = 0.589).Conclusions: The metabolism of ¹³C-AA was not modified by age, whereas ¹³C-EPA metabolism was slightly but significantly different in old compared with young men. The higher plasma ¹³C-DHA seen in old men may be a result of slower plasma DHA clearance with age. This trial was registered at clinicaltrials.gov as NCT02957188.

Plasma Phosphatidylethanolamine and Triacylglycerol Fatty Acid Concentrations are Altered in Major Depressive Disorder Patients with Seasonal Pattern

Disturbances in peripheral and brain lipid metabolism, including the omega-3 fatty acid docosahexaenoic acid (DHA), have been reported in major depressive disorder (MDD). However, these changes have yet to be confirmed in MDD with seasonal pattern (MDD-s), a subtype of recurrent MDD. The present exploratory study quantified plasma plasmalogen and diacyl-phospholipid species, and fatty acids within total phospholipids, cholesteryl esters, triacylglycerols and free fatty acids in non-medicated MDD-s participants (n = 9) during euthymia in summer or fall, and during depression in winter in order to screen for potential high sensitivity lipid biomarkers. Triacylglycerol alpha-linolenic acid concentration was significantly decreased, and myristoleic acid concentration was significantly increased, during winter depression compared to summer-fall euthymia. 1-stearyl-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine, a diacyl-phospholipid containing stearic acid and DHA, was significantly decreased in winter depression. Concentrations of cholesteryl ester oleic acid and several polyunsaturated fatty acids between summer/fall and winter increased in proportion to the increase in depressive symptoms. The observed changes in lipid metabolic pathways in winter-type MDD-s offer new promise for lipid biomarker development.

A Novel NF-κB Inhibitor, Edasalonexent (CAT-1004), in Development as a Disease-Modifying Treatment for Patients With Duchenne Muscular Dystrophy: Phase 1 Safety, Pharmacokinetics, and Pharmacodynamics in Adult Subjects

In Duchenne muscular dystrophy (DMD), NF‐κB is activated in skeletal muscle from infancy regardless of the underlying dystrophin mutation and drives inflammation and muscle degeneration while inhibiting muscle regeneration. Edasalonexent (CAT‐1004) is a bifunctional orally administered small molecule that covalently links 2 compounds known to inhibit NF‐κB, salicylic acid and docosahexaenoic acid (DHA). Edasalonexent is designed to inhibit activated NF‐κB upon intracellular cleavage to these bioactive components. Preclinical data demonstrate disease‐modifying activity in DMD animal models. Three placebo‐controlled studies in adult subjects assessed the safety, pharmacokinetics, and pharmacodynamics of single or multiple edasalonexent doses up to 6000 mg. Seventy‐nine adult subjects received edasalonexent, and 25 received placebo. Pharmacokinetic results were consistent with the intracellular cleavage of edasalonexent to its active components. Food increased plasma exposures of edasalonexent and salicyluric acid, an intracellularly formed metabolite of salicylic acid. The NF‐κB pathway and proteosome gene expression profiles in peripheral mononuclear cells were significantly decreased (P = .02 and P = .002, respectively) after 2 weeks of edasalonexent treatment. NF‐κB activity was inhibited following a single dose of edasalonexent but not by equimolar doses of salicylic acid and DHA. Edasalonexent was well tolerated, and the most common adverse events were mild diarrhea and headache. In first‐in‐human studies, edasalonexent was safe, well tolerated, and inhibited activated NF‐κB pathways, suggesting potential therapeutic utility in DMD regardless of the causative dystrophin mutation, as well as other NF‐κB–mediated diseases.

Balancing the benefits and costs of traditional food substitution by indigenous Arctic women of childbearing age: Impacts on persistent organic pollutant, mercury, and nutrient intakes

For indigenous Arctic Canadians, traditional food consumption represents a key source of nutrients and environmental contaminants. Particularly, ingestion of marine mammal blubber and meat may lead to persistent organic pollutant levels and mercury intakes that exceed regulatory thresholds for sensitive populations. We investigated whether temporary adjustments to the consumption of traditional food derived from marine mammals appreciably impacted contaminant exposure and nutrient intakes among indigenous women of childbearing age. Such adjustments can be motivated by the desire to lower contaminant exposure or to increase nutrition, or by the diminishing availability of other traditional food sources. We combined the contaminant fate and transport model GloboPOP with the food chain bioaccumulation model ACC-Human Arctic to simulate polychlorinated biphenyl exposures in female 2007-08 Inuit Health Survey participants. We also calculated daily mercury and nutrient intake rates. Our results suggest that a temporary decrease in marine mammal consumption is largely ineffective at reducing exposure to polychlorinated biphenyls, because of their long elimination half-lives. In contrast, substitution of marine mammals was highly efficient at reducing mercury intake, but also appreciably lowered intakes of iron, manganese, selenium, and ω-3 polyunsaturated fatty acids. The impact of increasing intake of traditional food derived from marine mammals during childbearing age greatly depended on baseline consumption rates; replacement is ill-advised for those who already consume a lot of traditional food due to greater polychlorinated biphenyl and mercury exposures, while replacement was potentially beneficial for those with very limited marine mammal consumption due to increased nutrient intakes. Our calculations primarily suggest that considering baseline traditional food intake rates is critical to devising reproductive dietary adjustment strategies that maximize nutrient intake while minimizing environmental contaminant exposure.

Plasma n-3 fatty acids and clinical outcomes in recent-onset rheumatoid arthritis

A randomised controlled trial (RCT) of high-dose v. low-dose fish oil in recent-onset rheumatoid arthritis (RA) demonstrated that the group allocated to high-dose fish oil had increased remission and decreased failure of disease-modifying anti-rheumatic drug (DMARD) therapy. This study examines the relationships between plasma phospholipid levels of the n-3 fatty acids in fish oil, EPA and DHA, and remission and DMARD use in recent-onset RA. EPA and DHA were measured in blood samples from both groups of the RCT. The data were analysed as a single cohort, and Cox proportional hazards models were used to examine relationships between plasma phospholipid (PL) EPA and DHA and various outcome measures. When analysed as a single cohort, plasma PL EPA was related to time to remission, with a one unit increase in EPA (1% total fatty acids) associated with a 12% increase in the probability of remission at any time during the study period (hazard ratio (HR)=1.12; 95% CI 1.02, 1.23; P=0.02). Adjustment for smoking, anti-cyclic citrullinated peptide antibodies and 'shared epitope' HLA-DR allele status did not change the HR. Plasma PL EPA, adjusted for the same variables, was negatively related to time to DMARD failure (HR=0.85; 95% CI 0.72, 0.99; P=0.047). The HR for DHA and time to remission or DMARD failure were similar in magnitude to those for EPA, but not statistically significant. Biomarkers of n-3 status, such as plasma PL EPA, have the potential to predict clinical outcomes relevant to standard drug treatment of RA patients.

Eicosapentaenoic acid suppression of systemic inflammatory responses and inverse up-regulation of 15-deoxyΔ(12,14) prostaglandin J2 production

BACKGROUND AND PURPOSE

Eicosapentaenoic acid (EPA) has been shown to suppress immune cell responses, such as cytokine production and downstream PG production in vitro. Studies in vivo, however, have used EPA as a minor constituent of fish oil with variable results. We investigated the effects of EPA on systemic inflammatory responses as pure EPA has not been evaluated on immune/inflammatory responses in vivo.

EXPERIMENTAL APPROACH

Rabbits were administered polyinosinic: polycytidylic acid (poly I:C) i.v. before and after oral treatment with EPA for 42 days (given daily). The responses to IL-1β and TNF-α were also studied. Immediately following administration of poly I:C, body temperature was continuously monitored and blood samples were taken. Plasma levels of IL-1β, PGE2 (PGE2), and 15-deoxy-Δ(12,14)-PGJ2 (15d-PGJ2) were measured by enzyme immunoassay.

KEY RESULTS

Following EPA treatment, the fever response to poly I:C was markedly suppressed compared with pretreatment responses. This was accompanied by a parallel reduction in the poly I:C-stimulated elevation in plasma levels of IL-1β and PGE2. Paradoxically, the levels of 15d-PGJ2 were higher following EPA treatment. EPA treatment did not significantly alter the fever response or plasma levels of PGE2 in response to either IL-1β or TNF-α.

CONCLUSION AND IMPLICATIONS

Oral treatment with EPA can suppress immune/inflammatory responses in vivo via a suppression of upstream cytokine production resulting in a decreased fever response and indirectly reducing circulating levels of PGE2. EPA also enhances the production of the cytoprotective prostanoid 15d-PGJ2 indicating the therapeutic benefit of EPA.

Maternal PUFA status and offspring allergic diseases up to the age of 18 months

Studies have suggested that maternal PUFA status during pregnancy may influence early childhood allergic diseases, although findings are inconsistent. We examined the relationship between maternal PUFA status and risk of allergic diseases in early childhood in an Asian cohort. Maternal plasma samples from the Growing Up in Singapore Towards Healthy Outcomes mother–offspring cohort were assayed at 26–28 weeks of gestation for relative abundance of PUFA. Offspring (n 960) were followed up from 3 weeks to 18 months of age, and clinical outcomes of potential allergic diseases (rhinitis, eczema and wheezing) were assessed by repeated questionnaires. Skin prick testing (SPT) was also performed at the age of 18 months. Any allergic disease with positive SPT was defined as having any one of the clinical outcomes plus a positive SPT. The prevalence of a positive SPT, rhinitis, eczema, wheezing and any allergic disease with positive SPT was 14·1 % (103/728), 26·5 % (214/808), 17·6 % (147/833), 10·9 % (94/859) and 9·4 % (62/657), respectively. After adjustment for confounders, maternal total n-3, n-6 PUFA status and the n-6:n-3 PUFA ratio were not significantly associated with offspring rhinitis, eczema, wheezing, a positive SPT and having any allergic disease with positive SPT in the offspring (P>0·01 for all). A weak trend of higher maternal n-3 PUFA being associated with higher risk of allergic diseases with positive SPT in offspring was observed. These findings do not support the hypothesis that the risk of early childhood allergic diseases is modified by variation in maternal n-3 and n-6 PUFA status during pregnancy in an Asian population.

The importance of choosing the appropriate matrix to validate a bioanalytical method according to the study needs

Sylvain Lachance is a Bioanalytical Scientific Expert in the Bioanalytical Division of inVentiv Health Clinical Quebec City's (Canada) site, a CRO offering clinical, commercial and consulting services to the healthcare industry. He is responsible for following up on the conduct of bioanalytical method development activities by enhancing the scientific and technical knowledge of the researchers, bioanalytical project coordinators and of the laboratory technicians. He assists bioanalytical project coordinators in investigations during bioanalyses and method validations. He has been working in the Bioanalytical Division of inVentiv Health Clinical for over 16 years, working as a Research Scientist, Chromatographic Specialist and Scientific Expert. He has worked on multiple method developments in HPLC and LC–MS/MS, specifically on troubleshooting. He has been involved in more than 70 posters and publications in the bioanalytical field for different scientific meetings.

Ann Lévesque obtained her PhD in Biochemistry at the Université Laval in Québec City in 1994 studying the biological actions of peptide analogs of the gastrin releasing peptide in the growth inhibition of cancer cells. Prior to joining inVentiv Health Clinical, she held management positions at other Contract Research Organizations. Her publications include over 100 posters, 17 scientific articles and book chapters in the clinical biochemistry and bioanalytical fields. Within inVentiv Health, Dr. Lévesque is responsible for managing the R&D and sample analysis teams performing bioanalytical analysis of small molecules and peptides. She is also acting as the Biomedical Laboratory Director accountable for the oversight of all activities related to the safety testing of samples from subjects enrolled in early stage clinical trials. Since joining the Bioanalytical Division, Dr. Lévesque has been instrumental in the great success of the laboratory by developing a culture of quality, innovation and value.

Validation guidelines from different agencies mainly recommend that matrix effect should be studied with hemolyzed and hyperlipidemic samples, while the European agency requires also to investigate matrix effect on special population. When studies are done in countries with different dietary habits, or when a medication is administered to decrease the concentration of the endogenous compounds, should the matrix effect in these conditions be evaluated? Herein, three case studies are described to show the importance of choosing the appropriate matrix for the bioanalytical method validations and for their use to analyze the study samples according to the conditions required by the clinical trials. The case studies presented are related to the use of the testosterone, Omega-3 and cortisol methods.

Incorporation and washout of n-3 PUFA after high dose intravenous and oral supplementation in healthy volunteers

BACKGROUND & AIMS

Although the physiological effects of n-3 polyunsaturated fatty acids (n-3PUFA) are generally thought to require several weeks of exposure to allow their incorporation into plasma membranes, intravenous (IV) n-3PUFA attenuate the cardiovascular and neuroendocrine response to stress within 3 h. Whether oral n-3 PUFA exert similar early effects remains unknown.

OBJECTIVE

To assess whether acute IV or short term oral n-3PUFA administration reproduces the metabolic effects of long term oral supplements during exercise, and how it relates to their incorporation into platelets and red blood cells (RBC) membranes.

DESIGN

Prospective single center open label study in 8 healthy subjects receiving a 3-h infusion of 0.6 g/kg body weight n-3PUFA emulsion, followed one week later by an oral administration of 0.6 g/kg over 3 consecutive days. Maximal power output (cycling exercise), maximal heart rate (HR), blood lactate at exhaustion, and platelet function were measured at baseline and after IV or 3-day oral supplementation; platelet and RBC membrane composition were assessed until 15 days after n-3PUFA administration.

RESULTS

Both IV and oral n-3PUFA significantly decreased maximal HR (-6% and -5%), maximal power output (-10%) and peak blood lactate (-47% and -52%) Platelet function tests were unchanged. The EPA and DHA membrane contents of RBC and platelets increased significantly, but only to 1.7-1.9% of fatty acid content.

CONCLUSION

The cardiovascular and metabolic effects of n-3 PUFA during exercise occur already within 1-3 days of exposure, and may be unrelated to changes in membranes composition. Effects occur within hours of administration and are unrelated to lipid membrane composition. Trial registered at clinicaltrials.gov as NCT00516178.

Treatment with omega-3 fatty acid ethyl-ester alters fatty acid composition of lipoproteins in overweight or obese adults with insulin resistance

INTRODUCTION

The effects of dietary fatty acid supplementation on lipoprotein fatty acid composition have rarely been described.

PATIENTS AND METHODS

Sixty-one overweight and obese adults with dyslipidemia and insulin resistance were randomized to placebo, 2g/day extended-release nicotinic acid (ERN), 4g/day prescription omega-3 fatty acid ethyl ester (P-OM3), or combination therapy for 16 weeks. Lipoprotein fatty acid composition was analyzed by gas chromatography pre- and post-treatment.

RESULTS

Treatment with P-OM3 or combination, but not ERN, increased proportions of eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid, and reduced those for arachidonic acid in all lipoprotein fractions, with greatest impact in the high-density lipoprotein fraction. P-OM3-induced changes in eicosapentaenoic acid within low-density lipoproteins and very low-density lipoproteins were associated with beneficial effects on mean arterial pressure and pulse pressure.

CONCLUSIONS

P-OM3 supplementation, with or without ERN, was associated with differentially altered lipoprotein fatty acid composition and improved blood pressure parameters.

Pharmacokinetics of Eicosapentaenoic Acid in Plasma and Red Blood Cells After Multiple Oral Dosing With Icosapent Ethyl in Healthy Subjects

Objective

Icosapent ethyl (IPE) is a prescription form of eicosapentaenoic acid (EPA) ethyl ester. This randomized, open-label study characterized EPA pharmacokinetics.

Methods

Four healthy subject groups received IPE for 28 days: three received 2 g/day (1 × 1,000 mg BID, 2 × 1,000 mg QD, or 2 × 500 mg BID); one received 4 g/day (2 × 1,000 mg BID) administered with meals. Blood sampling was before the morning dose on days 1, 14, 26, 28, and at specified intervals during an 18-day pharmacokinetic period. EPA was measured in plasma (total and unesterified) and red blood cells (RBCs) by liquid chromatography/tandem mass spectrometry.

Results

Mean plasma total EPA increased from 19 µg/mL to a peak (C_max) of 366 µg/mL at 5 hours postdosing 4 g/day IPE on Day 28. Mean RBC EPA C_max after 4 g/day was 89 µg/mL (baseline, 12 µg/mL). Mean steady state (SD) for half-life, clearance, and volume of distribution of total EPA were 79 (47) hours, 757 (283) mL/h, and 82 (56) L, respectively. Steady state for total and unesterified plasma EPA was reached by Day 28, whereas RBC levels were still increasing.

Conclusions

EPA pharmacokinetic profile demonstrated a slowly cleared, extensively distributed molecule with dose linearity and comparable exposures with BID and QD regimens.

Pretreatment with an intravenous lipid emulsion increases plasma eicosapentanoic acid and downregulates leukotriene b4, procalcitonin, and lymphocyte concentrations after open heart surgery in infants

BACKGROUND

The effect of providing a lipid emulsion containing medium-chain triglyceride (MCT), soybean oil, and fish oil in critically ill infants is not widely studied. This study investigated lipid emulsion effects on plasma phospholipids and immune biomarkers.

MATERIALS AND METHODS

Thirty-two infants undergoing cardiopulmonary bypass (CPB) and dependent on parenteral nutrition (PN) were randomized to receive either soybean oil (control, n = 16) or a 50:40:10 mixture of MCT, soybean oil, and fish oil (treatment, n = 16). PN was administered for 3 days preoperatively and 10 days postoperatively. Fatty acids, procalcitonin (PCT), leukotriene B4 (LTB4), and lymphocytes were quantified at baseline, before surgery, and days 1, 7 and 10 after surgery.

RESULTS

PCT was significantly lower in the treatment vs control group 1 day postoperatively (P = .01). The treatment group exhibited a lower ω-6 to ω-3 ratio (P = .0001) and a higher ω-3 concentration at all postoperative study periods (P = .001). Treatment resulted in higher (P < .05) plasma phospholipid eicosapentaenoic acid (EPA) on days 7 and 10, while α-linolenic acid, arachidonic acid, and docosahexaenoic acid remained constant. An increase in plasma phospholipid EPA concentration was associated with a decrease in plasma phospholipid LTB4 concentration (P < .05). On postoperative day 10, treatment infants with high Pediatric Risk of Mortality III scores exhibited a 45% lower lymphocyte concentration (P < .05).

CONCLUSION

These findings suggest that treating infants undergoing CPB with a lipid emulsion containing ω-3 improves fatty acid status and results in a lower inflammatory response after surgery. Overall, this alternative ω-3-enriched lipid emulsion may benefit clinical outcomes of critically ill infants after cardiac surgery.

Lipid mediator serum profiles in asthmatics significantly shift following dietary supplementation with omega-3 fatty acids

SCOPE

In contrast to well-characterized PUFA levels in serum, little is known regarding their downstream metabolic products. However, many of these compounds are lipid mediators with prominent roles during pro- and antiinflammatory processes.

METHODS AND RESULTS

In this double blind crossover study on asthmatics, shifts in serum levels of ω-3 and ω-6 PUFA-derived oxidized fatty acids (e.g. eicosanoids, oxylipins) were quantified following dietary fish oil supplementation. Serum was obtained from subjects following fasting at three occasions; (i) prior to supplementation, (ii) following a 3-week supplement intake of either placebo or fish oil, and (iii) following a 3-week washout period with a subsequent 3-week period of either fish oil or placebo supplement. A total of 87 oxylipins representing cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) metabolic pathways were screened via LC-MS/MS. The primary alterations observed were in CYP- and 15-LOX-derived EPA- and CYP-derived DHA oxylipins.

CONCLUSION

The results indicate that intake of an ω-3 rich diet alters not only the PUFA ratio, but also the ratio of downstream oxylipins. These data further support that dietary manipulation with ω-3 PUFAs affects not only PUFA levels, but importantly also the downstream metabolic profile.

Omega-3 polyunsaturated fatty acid profiling using fingertip-prick whole blood does not require overnight fasting before blood collection

Fatty acid profiling through the rapid analysis of capillary blood collected by fingertip prick could enable economical screening for omega-3 polyunsaturated fatty acid (PUFA) status, although the typical requirement of fasting prior to sample collection may limit application. We hypothesize that moderate changes in omega-3 biomarkers determined from fingertip-prick blood will occur and correspond to omega-3 PUFA content of the meals. Eight participants consumed a single breakfast with high fat, high fat with omega-3 functional foods, and low fat and low fat with fish oil capsules in a cross-over design. The fatty acid composition of fingertip-prick blood total lipid and venous blood erythrocyte total lipid, plasma total lipid, plasma triacylglycerol, and plasma phospholipids were analyzed at baseline and 1, 2, 3 and 4 hours after each single breakfast consumption. Omega-3 blood biomarkers; % of omega-3 highly unsaturated fatty acid (HUFA) in total HUFA, weight % of eicosapentaenoic acid+docosahexaenoic acid, weight % of eicosapentaenoic acid+omega-3 docosapentaenoic acid+docosahexaenoic acid, and the ratio of total omega-6 PUFA to total omega-3 PUFA in fingertip-prick blood, did not change from baseline during the postprandial period (P > .05). However, meal type yielded lower (P < .05) % omega-3 HUFA in total HUFA in the low fat meal (22.8 ± 3.9) as compared with the low fat with omega-3 (24.2 ± 3.9) and, the high fat (23.8 ± 4) meals. The ratio of total omega-6 PUFA to total omega-3 PUFA was generally higher in meals without omega-3 compared with omega-3. In conclusion, determinations of omega-3 status by fingertip-prick blood sampling may not require prior overnight fasting.

Comparison of the incorporation of orally administered DHA into plasma, erythrocyte and cheek cell glycerophospholipids

Adequate intake of n-3 fatty acids plays an important role in human health. The analysis of various blood lipids is used as a measure of fatty acid status in humans. Cheek cell phospholipids (PL) have also been proposed as biological markers, but are rarely used in clinical studies due to limitations in sample quality and quantity. An improved method for the analysis of cheek cell glycerophospholipid fatty acids is applied in a 29 d supplementation trial with 510 mg DHA daily. The DHA increases in cheek cell, plasma and erythrocyte glycerophospholipids are compared. High correlations are shown for glycerophospholipid DHA between cheek cells and plasma (r 0·88) and erythrocytes (r 0·76) before study commencement. After the daily supplementation of DHA, the half-maximal glycerophospholipid DHA level is reached after about 4 d in plasma, 6 d in erythrocytes and 10 d in cheek cells. The mean DHA increase (mol%) relative to baseline was most prominent in plasma (186 %), followed by cheek cells (180 %) and erythrocytes (130 %). Considering a lag phase of about 5 d, cheek cells reflect short-term changes in dietary fat uptake. Based on the data of the present study, they can be used alternatively to plasma and erythrocyte PL as non-invasive n-3 fatty acid status markers.

A short-term n-3 DPA supplementation study in humans

PURPOSE

Despite the detailed knowledge of the absorption and incorporation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into plasma lipids and red blood cells (RBC) in humans, very little is known about docosapentaenoic acid (DPA, 22:5 n-3). The aim of this study was to investigate the uptake and incorporation of pure DPA and EPA into human plasma and RBC lipids.

METHODS

Ten female participants received 8 g of pure DPA or pure EPA in randomized crossover double-blinded manner over a 7-day period. The placebo treatment was olive oil. Blood samples were collected at days zero, four and seven, following which the plasma and RBC were separated and used for the analysis of fatty acids.

RESULTS

Supplementation with DPA significantly increased the proportions of DPA in the plasma phospholipids (PL) (by twofold) and triacylglycerol (TAG) fractions (by 2.3-fold, day 4). DPA supplementation also significantly increased the proportions of EPA in TAG (by 3.1-fold, day 4) and cholesterol ester (CE) fractions (by 2.0-fold, day 7) and of DHA in TAG fraction (by 3.1-fold, day 4). DPA proportions in RBC PL did not change following supplementation. Supplementation with EPA significantly increased the proportion of EPA in the plasma CE and PL fractions, (both by 2.7-fold, day 4 and day 7) and in the RBC PL (by 1.9-fold, day 4 and day 7). EPA supplementation did not alter the proportions of DPA or DHA in any lipid fraction. These results showed that within day 4 of supplementation, DPA and EPA demonstrated different and specific incorporation patterns.

CONCLUSION

The results of this short-term study suggest that DPA may act as a reservoir of the major long-chain n-3 fatty acids (LC n-3 PUFA) in humans.

Determinants of DHA levels in early infancy: differential effects of breast milk and direct fish oil supplementation

INTRODUCTION

Although omega (n)-3 long-chain polyunsaturated fatty acids (LCPUFA), particularly docosahexaenoic acid (DHA), intakes are important during infancy, the optimal method of increasing infant status remains unclear. We hypothesized that high-dose infant fish oil supplementation would have greater relative effects upon n-3 LCPUFA status at six months of age than breast milk fatty acids.

PATIENTS AND METHODS

Infants (n=420) were supplemented daily from birth to six months with fish oil or placebo. In a subset of infants, LCPUFA levels were measured in cord blood, breast milk and in infant blood at 6 months.

RESULTS

DHA levels increased in the fish oil group relative to placebo (p<05). Breast milk DHA was the strongest predictor of infant erythrocyte DHA levels (p=<001). This remained significant after adjustment for cord blood DHA, supplementation group and adherence.

CONCLUSION

In this cohort, breast milk DHA was a greater determinant of infant erythrocyte n-3 LCPUFA status, than direct supplementation with fish oil.

Dietary methods and biomarkers of omega 3 fatty acids: a systematic review

The aims of the present study were to review the validity of dietary methods used to measure the usual long chain (LC) omega-3 polyunsaturated fatty acid (n-3 PUFA) intake of a population and to assess the usefulness of different biomarkers of n-3 PUFA in healthy humans. Two systematic literature searches were conducted until May 2011 to update previous systematic reviews. The first literature search aimed to find studies validating the methodology used for measuring the dietary intake of n-3 PUFA. The second search aimed to find human intervention studies in which n-3 PUFA status changed after 2 weeks of n-3 PUFA supplementation. Sixteen studies were identified for inclusion in the first review. Correlation coefficients between fatty acids in subcutaneous fat or blood lipids and dietary intake of n-3 PUFA from different questionnaires were similar. Subcutaneous fat has been reported as the best reference method for some authors, and these studies showed moderate correlation coefficients with no dietary intake method being superior to any other. As for the evaluation of biomarkers of docosahexaenoic acid (DHA, 22 : 6 n-3) and eicosapentaenoic acid (EPA, 20 : 5n-3) status in response to supplementation, the new search reaffirmed and reinforced the evidence supporting that plasma phospholipid DHA, erythrocyte DHA, and platelet DHA were all effective and robust biomarkers of DHA status. Our findings only confirmed earlier studies and did not provide evidence for reaching new conclusions.

Assessment of blood measures of n-3 polyunsaturated fatty acids with acute fish oil supplementation and washout in men and women

Changes in n-3 highly unsaturated fatty acids (HUFA, > or =20 carbons and > or =3 carbon-carbon double bonds) at baseline, during fish oil supplementation (4 weeks) and during washout (8 weeks) were compared in venous plasma, erythrocytes, whole blood and fingertip prick blood (weeks 0, 4, 8 and 12) with additional weekly fingertip prick samples. Correlations between the various blood fractions were slightly stronger when n-3 HUFA status was expressed as the percentage of n-3 HUFA in total HUFA as compared with the sum of EPA and DHA. Increases and decreases in n-3 HUFA were more dramatic in plasma, and EPA responded rapidly (within 1 week) with fish oil supplementation and cessation. Sex differences in the proportions of n-3 HUFA in blood were also apparent at baseline with females (n=7) having a tendency for higher docosahexaenoic acid (DHA, 22:6n-3) relative to eicosapentaenoic acid (EPA, 20:5n-3) and n-3 docosapentaenoic acid (DPAn-3, 22:5n-3) as compared with males (n=9). Further n-3 biomarker research in larger populations is required.

Methods of assessment of n-3 long-chain polyunsaturated fatty acid status in humans: a systematic review

BACKGROUND

The availability of reliable biomarkers of n-3 (omega-3) long-chain polyunsaturated fatty acid (LCPUFA) status is a prerequisite for linking dietary n-3 LCPUFA status to clinical outcomes.

OBJECTIVE

The objective of this meta-analysis was to assess the usefulness of different biomarkers of n-3 LCPUFA status in healthy humans.

DESIGN

We searched Ovid MEDLINE, EMBASE (Ovid), and Cochrane databases from inception to September 2007 for human intervention studies in which n-3 LCPUFA status changed after > or =2 wk of n-3 LCPUFA supplementation. We used formal inclusion/exclusion criteria and applied standard procedures for data extraction, validity assessment, and meta-analysis.

RESULTS

We included 41 studies (34 randomized controlled trials and 7 before-after studies) reporting on 18 different biomarkers. The data allowed specific evaluation of biomarkers of docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) status in response to supplementation. There were sufficient data to determine that plasma DHA, plasma phospholipid DHA, plasma triacylglycerol DHA, plasma cholesteryl ester DHA, plasma nonesterified DHA, erythrocyte DHA, erythrocyte phospholipid DHA, and platelet DHA were all effective biomarkers of DHA status and that plasma phospholipid EPA was an effective marker of EPA status. Plasma phospholipid DHA appears to be a good marker of DHA status in adult men and women irrespective of DHA baseline status or supplementation dose, but its usefulness in other population subgroups is unclear.

CONCLUSION

There appears to be a range of useful biomarkers of DHA status in humans, but further research is needed to characterize which work best in particular population subgroups.

Plasma n-3 fatty acid response to an n-3 fatty acid supplement is modulated by apoE ɛ4 but not by the common PPAR-α L162V polymorphism in men

The risk of Alzheimer's disease is increased for carriers of apoE4 (E4) or the PPAR-α L162V polymorphism (L162V), but it is decreased in fish and seafood consumers. The link between high fish intake and reduced risk of cognitive decline in the elderly appears not to hold in carriers of E4, possibly because better cognition is linked to EPA+DHA in the blood, but only in non-carriers of E4. As yet, no such studies exist in carriers of L162V. Our objective was to determine whether the plasma fatty acid response to a dietary supplement of EPA+DHA was altered in carriers of L162V and/or E4. This was an add-on project; in the original study, men were selected based on whether or not they were carriers of L162V (n 14 per group). E4 status was determined afterwards. All subjects received an EPA+DHA supplement for 6 weeks. L162V polymorphism did not interact with the supplement in a way to alter EPA and DHA incorporation into plasma lipids. However, when the groups were separated based on the presence of E4, baseline EPA and DHA in plasma TAG were 67 and 60 % higher, respectively, in E4 carriers. After the supplementation, there were significant gene × diet interactions in which only non-carriers had increased EPA and DHA in plasma NEFA and TAG, respectively.

Effect of the dietary fat quality on insulin sensitivity

Recent evidence shows that specific fatty acids affect cell metabolism, modifying the balance between fatty acid oxidation and lipogenesis. These effects may have important implications in addressing the present epidemic of nutrition-related chronic disease. Intake of dietary saturated and n-6 PUFA have increased while n-3 fatty acid intake has decreased. Obesity, type 2 diabetes and insulin resistance are highly prevalent, and both are strongly related to disorders of lipid metabolism characterized by an increased plasma and intracellular fatty acid availability. Thus, it has been hypothesized that change in the quality of dietary fat supply is able to modify the degree of insulin sensitivity. Animal studies provide support for this notion. However, there is limited human data either from normal or diabetic subjects. This review aims to analyse human studies that address this question. To this purpose, the experimental design, dietary compliance, insulin-sensitivity method used and confounding variables are discussed in order to identify the role of dietary fat quality as a risk factor for insulin resistance. Most studies (twelve of fifteen) found no effect relating to fat quality on insulin sensitivity. However, multiple study design flaws limit the validity of this conclusion. In contrast, one of the better designed studies found that consumption of a high-saturated-fat diet decreased insulin sensitivity in comparison to a high-monounsaturated-fat diet. We conclude that the role of dietary fat quality on insulin sensitivity in human subjects should be further studied, using experimental designs that address the limitations of existing data sets.

Incorporation and washout of n-3 polyunsaturated fatty acids after diet supplementation in clinical studies

Current evidence suggests that at least part of the cardioprotective benefits of consumption of long-chain n-3 polyunsaturated fatty acids (PUFAs) relates to their incorporation into the phospholipids of cardiac cell membranes. Dietary supplementation with purified extracts of n-3 PUFAs derived from fish oil rapidly alters the composition of fatty acids in blood cell membranes and in other tissues. The present review summarises the time-course and dose-dependent incorporation and washout of n-3 PUFAs in the clinical setting and discusses the implications of these pharmacokinetic data in terms of biological effects.

The effect of altering the 20:5n-3 and 22:6n-3 content of a meal on the postprandial incorporation of n-3 polyunsaturated fatty acids into plasma triacylglycerol and non-esterified fatty acids in humans

Previous studies suggest that consuming meals containing large amounts of fish oil is associated with selective postprandial incorporation of 20:5n-3 and 22:6n-3 into plasma non-esterified fatty acids (NEFA). We investigated the effect of consuming meals containing different amounts of 20:5n-3 and 22:6n-3 comparable to dietary habits of western populations on the postprandial incorporation of 18:3n-3, 20:5n-3 and 22:6n-3 into plasma triacylglycerol (TAG) and NEFA over 6h in middle aged subjects. 20:5n-3 incorporation into plasma TAG was greater than 22:6n-3 irrespective of the test meal. Conversely, 22:6n-3 incorporation into plasma NEFA was greater than 20:5n-3, irrespective of the test meal. There was no effect of the amount of 20:5n-3+22:6n-3 in the test meal on the 18:3n-3 incorporation into plasma TAG or NEFA. These findings suggest differential metabolism of 20:5n-3 and 22:6n-3 in the postprandial period when consumed in amounts typical of western dietary habits.

Eicosapentaenoic acid and docosahexaenoic acid from fish oils: differential associations with lipid responses

Fish-oil supplementation can reduce circulating triacylglycerol (TG) levels and cardiovascular risk. This study aimed to assess independent associations between changes in platelet eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and fasting and postprandial (PP) lipoprotein concentrations and LDL oxidation status, following fish-oil intervention. Fifty-five mildly hypertriacylglycerolaemic (TG 1·5–4·0 mmol/l) men completed a double-blind placebo controlled cross over study, where individuals consumed 6 g fish oil (3 g EPA+DHA) or 6 g olive oil (placebo)/d for two 6-week intervention periods, with a 12-week wash-out period in between. Fish-oil intervention resulted in a significant increase in the platelet phospholipid EPA (+491 %,P<0·001) and DHA (+44 %,P<0·001) content and a significant decrease in the arachidonic acid (-10 %,P<0·001) and γ-linolenic acid (-24 %,P<0·001) levels. A 30 % increase inex vivoLDL oxidation (P<0·001) was observed. In addition, fish oil resulted in a significant decrease in fasting and PP TG levels (P<0·001), PP non-esterified fatty acid (NEFA) levels, and in the percentage LDL as LDL-3 (P=0·040), and an increase in LDL-cholesterol (P=0·027). In multivariate analysis, changes in platelet phospholipid DHA emerged as being independently associated with the rise in LDL-cholesterol, accounting for 16 % of the variability in this outcome measure (P=0·030). In contrast, increases in platelet EPA were independently associated with the reductions in fasting (P=0·046) and PP TG (P=0·023), and PP NEFA (P=0·015), explaining 15–20 % and 25 % of the variability in response respectively. Increases in platelet EPA+DHA were independently and positively associated with the increase in LDL oxidation (P=0·011). EPA and DHA may have differential effects on plasma lipids in mildly hypertriacylglycerolaemic men.

Sources of the very-long-chain unsaturated omega-3 fatty acids: eicosapentaenoic acid and docosahexaenoic acid

PURPOSE OF REVIEW

We assess the toxicological, environmental and economic aspects of sources of fish oil and omega-3 fatty acids (n-3 fatty acids).

RECENT FINDINGS

Fish oils are the most common source of the very-long-chain n-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid, which have protective and beneficial effects on conditions such as cardiovascular, inflammatory, or neurological diseases. Fish oils can also be potential hazards for human health, because of external pollutants bio-accumulating in fish. Wild and farmed fish are generally both similar in n-3 fatty acid content but may vary in terms of potential toxins. Reports on aquaculture and fish oil production, and other sources of n-3 fatty acids, are reviewed to assess which may be more suitable economically and ecologically for higher fish oil production and availability.

SUMMARY

Although today's fish oil production meets demand, it is likely that this will not be able to increase without adversely affecting the world's wild stock of fish. Neither wild nor farmed fish constitute a sustainable source of n-3 fatty acids for supplementation. Solutions may be found through the evolution of the current aquaculture system or the utilization of alternative manufacturing sources for increasing intakes of n-3 fatty acids.

Distribution, interconversion, and dose response of n-3 fatty acids in humans

n-3 Fatty acids have important visual, mental, and cardiovascular health benefits throughout the life cycle. Biodistribution, interconversion, and dose response data are reviewed herein to provide a basis for more rational n-3 dose selections. Docosahexaenoic acid (DHA) is the principal n-3 fatty acid in tissues and is particularly abundant in neural and retinal tissue. Limited storage of the n-3 fatty acids in adipose tissue suggests that a continued dietary supply is needed. A large proportion of dietary alpha-linolenic acid (ALA) is oxidized, and because of limited interconversion of n-3 fatty acids in humans, ALA supplementation does not result in appreciable accumulation of long-chain n-3 fatty acids in plasma. Eicosapentaenoic acid (EPA) but not DHA concentrations in plasma increase in response to dietary EPA. Dietary DHA results in a dose-dependent, saturable increase in plasma DHA concentrations and modest increases in EPA concentrations. Plasma DHA concentrations equilibrate in approximately 1 mo and then remain at steady state throughout supplementation. DHA doses of approximately 2 g/d result in a near maximal plasma response. Both dietary DHA and EPA reduce plasma arachidonic acid concentrations. Tissue contents of DHA and EPA also increase in response to supplementation with these fatty acids. Human milk contents of DHA are dependent on diet, and infant DHA concentrations are determined by their dietary intake of this fatty acid. We conclude that the most predictable way to increase a specific long-chain n-3 fatty acid in plasma, tissues, or human milk is to supplement with the fatty acid of interest.

Plasma lipids and fatty acid composition in parrots in relation to the intake of alpha-linolenic acid from two feed mixtures

The main objective of this study was to find out whether the content of alpha-linolenic acid (ALA) in plasma cholesteryl-esters (CE) or triglycerides (TG) in parrots might serve as an index of ALA intake. The intake of ALA might be a risk factor for atherosclerosis, but on the basis of the fatty acid composition of seed mixtures the intake is difficult to assess due to selective eating of seeds. Parrots were fed two seed mixtures that differed in ALA content according to a cross over design. The macronutrient composition of the diets supplied differed from that of the diets consumed. The diets consumed had higher levels of dry matter, crude protein, crude fat and energy, and lower levels of crude fibre and crude ash. The ALA content, expressed as g/kg diet, was similar for the diet supplied and that consumed, irrespective of the type of diet. The diets had no systematic effect on plasma lipid concentrations. There were marked differences in plasma cholesterol concentrations between parrot species. When the diet with the low ALA content was fed (0.8% ALA of total fatty acids consumed, 1.1 g ALA/kg of diet consumed), the plasma CE and TG did not contain detectable ALA amounts. When the diet with the high ALA content was fed (4.2% ALA of total fatty acids consumed, 6.1 g ALA/kg of diet consumed), the plasma CE and TG contained about 1% ALA of total fatty acids. It is suggested that the content of ALA in plasma CE and TG might be used as an indicator of ALA intake.

Tissue accretion and milk content of docosahexaenoic acid in female rats after supplementation with different docosahexaenoic acid sources

BACKGROUND

Docosahexaenoic acid (DHA) is highly concentrated in the mammalian nervous and visual system. The fatty acid, which is required by the fetus and the newborn, is supplied by the mother from their tissue reservoirs. It has been suggested that mother's supplementation with DHA during pregnancy and even before pregnancy. Different sources of DHA are available for supplementation such as: single-cell algae triglycerides (TG), egg's yolk phospholipids (PL), DHA ethyl esther (EE), and sn-2 DHA monoacylglyceride (MG). We evaluated comparatively the effectiveness of these different DHA sources to produce tissue DHA accretion and to increase milk DHA content.

METHODS

Female Wistar rats fed a diet which provided no DHA, were daily supplemented by 40 days before mating (BM) and during the pregnancy with either TG, PL, EE, or MG to an amount which provided 8 mg/kg b.w. of DHA. Samples of blood plasma, erythrocytes, hepatic and adipose tissue were obtained from rats at the BM condition and after the delivery (AD), and milk samples were also obtained from the gastric content of the pups nursed by the rats at day 3, 11 and 20 of suckling. Samples were processed to assess DHA and arachidonic acid (AA) content by gas-chromatography.

RESULTS

TG, PL, EE, and MG supplementation produced a similar intestinal absorption of DHA as estimated from the plasma DHA at the BM condition. However, PL and MG supplementation produced a higher accretion of DHA into erythrocytes, hepatic, and adipose tissue than TG and EE supplementation at the BM condition. AA content was not modified by the different supplementing oils. A reduction of the DHA content of plasma, erythrocytes, hepatic and adipose tissue at the AD condition was observed, and a reduction of AA for the hepatic and adipose tissues was also observed, suggesting the importance of these tissues as DHA and AA reservoirs. Milk secretion from PL and MG supplemented rats showed a higher DHA content than secretion from TG- and EE-supplemented rats.

CONCLUSIONS

We conclude that PL and MG supplementation provides higher tissue DHA accretion and higher milk DHA content than TG and EE supplementation. However, we were not able to visualize the comparative advantages derived from PL vs. MG supplementation.

Effect of supplementation with docosahexaenoic acid ethyl ester and sn-2 docosahexaenyl monoacylglyceride on plasma and erythrocyte fatty acids in rats

BACKGROUND/AIMS

Docosahexaenoic acid (C22:6, DHA) is an omega-3 fatty acid required for the normal development of the mammalian nervous and visual system. DHA is provided by the mother during pregnancy and lactating period. Mother's DHA supplementation during pregnancy, and even before pregnancy, has been suggested. DHA can be provided by marine oils, egg's yolk phospholipids, single cell algae oils, the pure fatty acid, or by the ethyl ester derivative (DHA-EE). Another way to provide DHA can be by sn-2 docosahexaenyl monoacylglyceride (DHA-MG), obtained by the treatment of fish oil with stereospecific lipases. sn-2 Fatty acid monoacylglycerides can be more easily absorbed at the intestine than other fatty acid derivatives.

METHODS

Female rats fed with a synthetic, which provided essentially no DHA, received a 40-day supplementation of either DHA-EE or DHA-MG. Plasma and erythrocyte fatty acid composition were assessed by gas chromatography at day 0 and 40 of supplementation.

RESULTS

DHA-EE increased plasma and erythrocyte DHA by 15 and 11.9%, respectively, with no modification of arachidonic acid (AA) content. DHA-MG supplementation increased plasma and erythrocyte DHA by 24 and 23.8%, respectively, but reduced AA by 5.5 and 3%, respectively.

CONCLUSIONS

We conclude that in the rat, DHA-MG supplementation allows a higher plasma and erythrocyte DHA content than DHA-EE with minor modification of AA content.

Moderate fish-oil supplementation reverses low-platelet, long-chain n-3 polyunsaturated fatty acid status and reduces plasma triacylglycerol concentrations in British Indo-Asians

BACKGROUND

The mechanisms involved in the increased mortality from coronary artery disease in British Indo-Asians are not well understood.

OBJECTIVES

This study aimed to investigate whether British Indo-Asian Sikhs have higher plasma triacylglycerol concentrations, lower platelet phospholipid levels, and lower dietary intakes of long-chain n-3 polyunsaturated fatty acids (PUFAs) than do age- and weight-matched Europeans and whether moderate dietary fish-oil intake can reverse these differences.

DESIGN

A randomized, double-blind, placebo-controlled, parallel, fish-oil intervention study was performed. After a 2-wk run-in period, 44 Europeans and 40 Indo-Asian Sikhs were randomly assigned to receive either 4.0 g fish oil [1.5 g eicosapentaenoic acid (EPA) and 1.0 g docosahexaenoic acid (DHA)] or 4.0 g olive oil (control) daily for 12 wk.

RESULTS

At baseline, the Indo-Asians had significantly higher plasma triacylglycerol, small dense LDL, apolipoprotein B, and dietary and platelet phospholipid n-6 PUFA values and significantly lower long-chain n-3 PUFAs (EPA and DHA) than did the Europeans. A significant decrease in plasma triacylglycerol, plasma apolipoprotein B-48, and platelet phospholipid arachidonic acid concentrations and a significant increase in plasma HDL concentrations and platelet phospholipid EPA and DHA levels were observed after fish-oil supplementation. No significant effect of ethnicity on the responses to fish-oil supplementation was observed.

CONCLUSIONS

Moderate fish-oil supplementation contributes to a reversal of lipid abnormalities and low n-3 PUFA levels in Indo-Asians and should be considered as an important, yet simple, dietary manipulation to reduce CAD risk in Indo-Asians with an atherogenic lipoprotein phenotype.

Short term effects of dietary medium-chain fatty acids and n-3 long-chain polyunsaturated fatty acids on the fat metabolism of healthy volunteers

BACKGROUND

The amount and quality of dietary fatty acids can modulate the fat metabolism.

OBJECTIVE

This dietary intervention is based on the different metabolic pathways of long-chain saturated fatty acids (LCFA), which are mostly stored in adipocytic triacylglycerols, medium-chain fatty acids (MCFA) which are preferentially available for hepatic mitochondrial beta-oxidation and n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) suggested to modulate fat oxidation and storage by stimulating the peroxisomal beta-oxidation. Combined dietary MCFA and n-3 LCPUFA without LCFA may synergistically stimulate fatty acid oxidation resulting in blood lipid clearance and LCFA release from adipocytes.

DESIGN

In a short term, parallel, randomized, double-blind trial effects on the fatty acid metabolism of 10 healthy volunteers (Body Mass Index 25-30) of a formula containing 72% MCFA and 22% n-3 LCPUFA without LCFA (intake: 1.500 kcal/day; fat: 55.5% of energy) were measured in comparison to an isoenergetic formula with equal fat amount and LCFA dominated lipid profile.

RESULTS

The plasma triacylglycerol (p < 0.1) and cholesterol (p < 0.05) content decreased in the test group. The n-3/n-6 LCPUFA (> or = C 20) ratio increased (p < 0.0001) after 4 days treatment. The LCFA content was similar in both groups despite missing LCFA in the test formula indicating LCFA release from adipocytes into the plasma. Both groups significantly reduced body weight considerably 4 kg (p < 0.01) and fat mass up to 50% of weight loss (p < 0.05).

CONCLUSION

Combined dietary 72% MCFA and 22% n-3 LCPUFA without LCFA stimulate the fatty acid oxidation and release from adipocytes without affecting any safety parameters measured.

Selective partitioning of dietary fatty acids into the VLDL TG pool in the early postprandial period

Circulating triacylglycerol (TG) arises mainly from dietary fat. However, little is known about the entry of dietary fat into the major TG pool, very low-density lipoprotein (VLDL) TG. We used a novel method to study the specific incorporation of dietary fatty acids into postprandial VLDL TG in humans. Eight healthy volunteers (age 25.4 +/- 2.2 years, body mass index 22.1 +/- 2.3 kg/m2) were fed a mixed meal containing 30 g fish oil and 600 mg [1-13C]palmitic acid. Chylomicrons and VLDL were separated using immunoaffinity against apolipoprotein B-100. The fatty acid composition of lipoproteins was analyzed by gas chromatography/mass spectrometry. [1-13C]palmitic acid started to appear in VLDL TG 3 h after meal intake, and a similar delay was observed for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Approximately 20% of dietary fatty acids entered the VLDL TG pool 6 h after meal intake. DHA was clearly overincorporated into this pool compared with [1-13C]palmitic acid and EPA. This seemed to depend on a marked elevation of this fatty acid in the nonesterified fatty acid pool. In summary, the contribution of dietary fatty acids to early postprandial VLDL TG is substantial. The role of DHA in VLDL TG production will require further investigation.

Serum fatty acid levels, dietary style and coronary heart disease in three neighbouring areas in Japan: the Kumihama study

CHD mortality is extremely low in Japan, particularly in rural districts, when compared with that in Western countries. This has been partly attributed to the difference in dietary lifestyle. We investigated the factors influencing CHD mortality in a rural coastal district of Japan, comprising mercantile, farming, and fishing areas with distinct dietary habits. We prospectively examined the incidence of CHD from 1994 to 1998, as well as coronary risk factors and serum fatty acid concentrations. The incidence of angina pectoris was significantly (P=0.01) lower in the fishing area than in the mercantile and farming areas. Blood pressure, physical activity, prevalence of diabetes, serum levels of uric acid and HDL-cholesterol were similar between the three areas. Total- and LDL-cholesterol levels were significantly lower but the smoking rate was markedly higher in the fishing area than in the other two areas. Serum levels of saturated fatty acids and n-6 polyunsaturated fatty acids (PUFA) were lowest in the fishing area, but n-3 PUFA did not differ significantly. The n-6:n-3 PUFA ratio was lowest and eicosapentaenoic:arachidonic acid was highest in the fishing area. Although many previous studies have emphasized the beneficial effect of n-3 PUFA in preventing CHD, the present study indicated that a lower intake of n-6 PUFA and saturated fatty acids has an additional preventive effect on CHD even when the serum level of n-3 PUFA is high because of high dietary fish consumption.

Fish oil containing phytosterol esters alters blood lipid profiles and left ventricle generation of thromboxane a(2) in adult guinea pigs

This study was designed to investigate the lipid-lowering ability of a novel dietary ingredient composed of phytosterols esterified to (n-3) polyunsaturated fatty acids (PUFA) [PS(n-3)]. Adult guinea pigs were fed a test diet supplemented with PS(n-3) (25 g/kg) and corn oil (CO, 5 g/kg), whereas the diet fed to control guinea pigs was supplemented with CO only (30 g/kg). Cholesterol was added to both diets (0.8 g/kg). After 3-4 wk of consuming the diets, serum total cholesterol (TC) and triacylglycerol (TAG) in the PS(n-3) group were 36 and 29% lower, respectively, than levels in controls (P < 0.05). The lower TC levels in the PS(n-3) group reflected a 38% reduction in non-HDL cholesterol (non-HDL-C), whereas the HDL-C concentration was unaffected. Analysis of cardiac left ventricle indicated that generation of the proaggregatory, arrhythmic eicosanoid, thromboxane A(2), was >60% lower in the PS(n-3)-supplemented guinea pigs than in CO controls (P < 0.001). This study demonstrates that the TAG-lowering and eicosanoid-modifying properties of the fish oil (n-3) PUFA are retained when they are provided in the diet in ester linkage with hypocholesterolemic phytosterols.

Fatty acid composition of plasma lipids in patients with pancreatic, lung and oesophageal cancer in comparison with healthy subjects

BACKGROUND & AIMS

Despite the general notion of impaired nutritional status in cancer patients, studies on fatty acid status in cancer patients are limited. The aim of the present study was to investigate whether plasma n-3 fatty acids concentrations are reduced in patients with different tumour types.

METHODS

We measured fatty acid composition in plasma phospholipids (PLs) and cholesteryl esters (CEs) in 71 newly diagnosed, untreated cancer patients of three tumour types: oesophageal or cardia cancer (n = 35), non-small cell lung cancer (n = 22) and pancreatic cancer (n = 15) and in 45 healthy subjects.

RESULTS

In pancreatic cancer, plasma n-3 fatty acids showed a substantial reduction in both plasma PLs and CES. Although n-3 fatty acids in lung cancer also tended to be reduced, this difference failed to reach statistical significance. n-3 Fatty acid levels were especially reduced in pancreatic cancer patients without diabetes mellitus, and in lung cancer patients with weight loss. In oesophageal cancer, n-3 fatty acid concentrations were comparable to those in healthy subjects.

CONCLUSION

We conclude that plasma n-3 fatty acid levels were reduced in pancreatic cancer, tended to be reduced in lung cancer, but were not altered in oesophageal cancer. Further studies are needed to assess the mechanisms underlying the observed changes in n-3 fatty acid concentrations.

Eicosapentaenoic acid and arachidonic acid: collaboration and not antagonism is the key to biological understanding

Much of the literature on omega-3 and omega-6 fatty acids suggests that desirable effects of omega-3 fatty acids are in part related to depletion of arachidonic acid (AA). However, in rats and humans, we have found that low doses of EPA actually elevate membrane AA phospholipid concentrations. In patients with schizophrenia, treatment with eicosapentaenoic acid (EPA) produced clinical improvement, but that improvement was greater at a dose of 2 g/day than at 4 g/day. The improvement was not significantly correlated with changes in either EPA or docosahexaenoic acid (DHA) but was highly significantly positively correlated with rises in red cell membrane AA. We suggest that elevation of concentrations of both AA and EPA in cell membranes may be important for health.

Reversibility of the changes induced by n-3 fatty acids in mouse plasma, liver and blood cell lipids

The changes induced by dietary n-3 fatty acids (FA) in the lipids and FA of plasma, liver and blood cells, and their reversibility, was studied in mice given a diet containing 9% fish oil (FO) for 2 weeks and then returned to, and kept for another 2 weeks on, the usual standard lab chow diet. In plasma, the concentrations of phospholipids (PL), mostly phosphatidylcholine (PC), triacylglycerols (TG), cholesterol and cholesterol esters (CE) decreased rapidly after starting the FO diet, and remained low from day 3 onwards. This decrease was concomitant with a remarkable reduction in the n-6 FA, especially 18:2n-6, not compensated for by the relative enrichment in n-3 FA induced by FO. In liver, TG and CE decreased and PL slightly increased, all of them showing reduced n-6/n-3 ratios. Sphingomyelin, which lacks polyunsaturated FA other than small amounts of 18:2 and 24:2n-6, showed altered ratios between its very long chain monoenes and saturates. In the washout phase, the most rapid event was an immediate increase in 18:2n-6 and after a few days in 20:4n-6 in plasma and liver, where most of the lipid and FA changes were reversed completely in about 10 days. In the case of blood cells even 2 weeks were insufficient for a reversal to the initial n-6/n-3 ratios. The lipid class responsible for this lack of reversibility was phosphatidylethanolamine, PC having returned to the initial fatty acid composition during the stated period.