Long-chain N-3 Polyunsaturated Fatty Acids Research Articles

Circulating Omega-3 Fatty Acids and Neovascular Age-Related Macular Degeneration

We assessed the associations of serum, red blood cell membranes (RBCM) and dietary long-chain n-3 polyunsaturated fatty acids (LC-PUFAs) with neovascular age-related macular degeneration (AMD). We included 290 patients of the Nutritional AMD Treatment 2 Study (NAT2) with neovascular AMD in one eye and early AMD lesions in the other eye, and 144 normal vision controls without AMD. Dietary intake of seafood was estimated by food frequency questionnaire. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) composition in serum and RBCM were determined by gas chromatography from 12-hour fasting blood samples and was expressed as percentages of total fatty acids profile. Logistic regressions estimated associations of neovascular AMD with dietary intake of seafood and circulating n-3 LC-PUFAs. Dietary oily fish and seafood intake were significantly lower in AMD patients than in controls. After adjustment for all potential confounders (age, sex, CFH Y402H, ARMS2 A69S, and ApoE4 polymorphisms, plasma triglycerides, hypertension, hypercholesterolemia, and family history of AMD), serum EPA was associated significantly with a lower risk for neovascular AMD (odds ratio [OR] = 0.41; 95% confidence interval [CI], 0.22-0.77; P = 0.005). Analysis of RBCM revealed that EPA and EPA+DHA were associated significantly with a lower risk for neovascular AMD (OR = 0.25; 95% CI, 0.13-0.47; P < 0.0001 and OR = 0.52; 95% CI, 0.29-0.94; P = 0.03, respectively). The RBCM EPA and EPA+DHA, as long-term biomarkers of n-3 dietary PUFA status, were associated strongly with neovascular AMD and may represent an objective marker identifying subjects at high risk for neovascular AMD, who may most benefit from nutritional interventions. (http://www.controlled-trials.com/isrctn number, ISRCTN98246501).

Increasing long-chain n-3PUFA consumption improves small peripheral artery function in patients at intermediate–high cardiovascular risk

Dietary long-chain n-3 polyunsaturated fatty acids (LCn-3PUFA) improve endothelial function in medium–large-sized arteries, but effects on small peripheral arteries, responsible for most arterial resistance, are little known. We investigated the effects of increasing LCn-3PUFA intake with the usual diet on small artery reactive hyperemia index (saRHI). Within a clinical trial evaluating the effects of 1 year of intensive lifestyle intervention versus standard care on cardiovascular markers in subjects at risk, we selected 108 participants regardless of treatment allocation (n=47 standard care; n=61 intensive intervention) with complete baseline and follow-up information on dietary, clinical, saRHI and biochemical data, including biomarkers of inflammation and endothelial activation. At the end of follow-up, saRHI increased across tertiles of change in dietary LCn-3PUFA. Subjects in the top tertile (increased LCn-3PUFA intake) increased serum ApoA1 and decreased hs-CRP, serum TNF-α, sICAM-1, sVCAM-1 and oxLDL from baseline. After pooling data, in unadjusted models, changes in saRHI significantly correlated to changes in LCn-3PUFA intake and ApoA1 (directly) and changes in systolic blood pressure, waist circumference, TNF-α, sVCAM-1 and sE-selectin (inversely). In a multivariate model, changes in dietary LCn-3PUFA were significantly associated with changes in saRHI [B=0.08 (95% confidence interval=0.083–0.291) for an increase by 100 mg/day]. Systolic blood pressure was inversely associated with saRHI changes [B=−0.203 (−0.441 to −0.029) for a 9-mmHg increase]. We conclude that increased dietary consumption of LCn-3PUFA might be a cost-effective strategy to improve peripheral vasoactivity.

Long chain n-3 polyunsaturated fatty acids and incidence rate of coronary artery calcification in Japanese men in Japan and white men in the USA: population based prospective cohort study

ObjectiveTo determine whether serum concentrations of long chain n-3 polyunsaturated fatty acids (LCn3PUFAs) contribute to the difference in the incidence rate of coronary artery calcification (CAC) between Japanese men in...

Long-chain n-3 polyunsaturated fatty acids intake and cardiovascular disease mortality risk in Japanese: A 24-year follow-up of NIPPON DATA80

BackgroundDietary intake of long-chain n-3 PUFA (LCn3FA) among Japanese is generally higher than that in Western populations. However, little is known whether an inverse association of LCn3FA with cardiovascular disease (CVD) risk exists in a population with higher LCn3FA intake. ObjectiveTo investigate the association between LCn3FA intake and the long-term risk of CVDs in a Japanese general population. MethodsWe followed-up a total of 9190 individuals (56.2% women, mean age 50.0 years) randomly selected from 300 areas across Japan and free from CVDs at baseline. Dietary LCn3FA intake was estimated using household weighed food records. Cox models were used to calculate multivariate-adjusted hazard ratios (HR) and confidence intervals (CI) according to sex specific quartiles of LCn3FA intake. ResultsDuring 24-year follow-up (192,897 person-years), 879 cardiovascular deaths were observed. The median daily intake of LCn3FA was 0.37% kcal (0.86 g/day). Adjusted HR for CVD mortality was lower in the highest quartile of LCn3FA intake (HR 0.80; 95% CI 0.66–0.96) compared with the lowest quartile, and the trend was statistically significant (P = 0.038). The similar but statistically non-significant trends were observed for coronary heart disease death and stroke death. In analyses by age groups, the inverse associations of LCn3FA intake with the risk of total CVD death and stroke death were significant in younger individuals (30–59 years at baseline). ConclusionLCn3FA intake was inversely and independently associated the long-term risk of total CVD mortality in a representative sample of Japanese with high LCn3FA intake.

Fish and fish oil intake in relation to risk of asthma: a systematic review and meta-analysis.

Although laboratory studies suggest that long-chain n-3 polyunsaturated fatty acids (LCn3PUFAs) may reduce risk of asthma, epidemiological data remain controversial and inconclusive. We quantitatively reviewed the epidemiological studies published through December 2012 in PubMed and EMBASE by using a fixed-effects or random-effects model. Eleven studies, comprised of 99,093 individuals (3,226 cases), were included in the final dataset. Of them, 7 studies examined associations between intake of fish or LCn3PUFA and risk of asthma: 4 studies in children (996 cases from 12,481 children) and 3 in adults (1,311 cases from 82,553 individuals). Two studies (69 cases from 276 infants) investigated LCn3PUFA levels in mothers’ milk, and two studies assessed maternal fish consumption (786 cases from 2,832 individuals) during lactation and/or plasma LCn3PUFA levels during pregnancy (64 cases from 951 infants) in relation to offspring’s asthma. The pooled relative risk of child asthma were 0.76 (95% CI, 0.61–0.94) for fish consumption and 0.71 (95% CI, 0.52–0.96) for LCn3PUFA intake. No statistically significant association was found in studies among adults. Epidemiological data to date indicate that fish or LCn3PUFA intake may be beneficial to prevent asthma in children. Further studies are needed to establish causal inference and to elucidate the potential mechanisms.

The effect of fatty acid positioning in dietary triacylglycerols and intake of long-chain n-3 polyunsaturated fatty acids on bone mineral accretion in growing piglets

Long-chain n-3 PUFA (LCPUFA) and palmitate (16:0) positioning in the triacylglycerol (TAG) of infant formula may affect calcium-uptake which could affect bone health. We investigated if a human milk fat substitute (HMFS) with a modified TAG structure holding 16:0 predominantly in the sn-2-position compared with a control (CONT) and if increasing n-3LCPUFA intake giving fish oil (FO) compared with sunflower oil (SO) would affect bone parameters in piglets in two sets of controlled 14d-interventions (n=12/group). We assessed this by dual-energy x-ray absorptiometry, and ex vivo peripheral quantitative computed tomography and mechanical strength. Bone mineral content (BMC) was higher in the FO compared to the SO-group (p=0.03). Despite similar weight gain in HMFS- and CONT-groups, body fat accumulation was higher with HMFS (p<0.001), and BMC, bone area (BA) and cortical BA in femur were lower (p=0.002, p=0.005, and p=0.02, respectively), indicating importance of both n-3LCPUFA and 16:0 TAG-positioning in infant formulas.

Eicosapentaenoic and Docosahexaenoic Acid Supplementations Reduce Platelet Aggregation and Hemostatic Markers Differentially in Men and Women

Although long-chain n3 polyunsaturated fatty acids [n3 PUFAs; eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] have been reported to reduce platelet aggregation, the available evidence on this is equivocal. We previously demonstrated that the acute effects of n3 PUFA supplementation on platelet aggregation are sex specific. We aimed to determine if this gender bias is maintained during long-term n3 PUFA supplementation and whether this translates to other hemostatic markers. A double-blinded, randomized, placebo controlled trial was conducted in 94 healthy men and women. Platelet aggregation, thromboxane (TX) B2, P-selectin (P-sel), von Willebrand factor (vWF), and plasminogen activator inhibitor-1 were measured at baseline and 4 wk postsupplementation with EPA-rich (1000 mg EPA:200 mg DHA) or DHA-rich (200 mg EPA:1000 mg DHA) oil capsules daily. The effects of n3 PUFA on platelet activity were compared between men and women. In men and women combined, EPA and DHA reduced platelet aggregation following 4 wk of supplementation relative to placebo (−11.8%, P = 0.016; and −14.8%, P = 0.001, respectively). In subgroup analyses, in men, only the EPA treatment reduced platelet aggregation by −18.4% compared with placebo (P = 0.005) and women (P = 0.011). In contrast, in women, only the DHA treatment reduced platelet aggregation (−18.9%) compared with placebo (P = 0.001) and men (P = 0.017). Significant sex × treatment interactions were also observed on hemostatic markers and uptake of n3 PUFAs. The significant interactions between sex and specific, supplemental, long-chain n3 PUFAs result in platelet aggregation being differentially affected in men and women. With respect to thrombotic disease risk, men are more likely to benefit from supplementation with EPA, whereas women are more responsive to DHA.

Correlations of n-3 (omega-3) fatty acid levels with lipoproteins: negative correlation with HDL-C after an oral load

Exogenous long-chain n-3 polyunsaturated fatty acids (LC-FA) are mainly incorporated into phospholipids in membranes and to some extent into cholesteryl esters. Limited data have been reported on the relative distribution of n-3 FA in lipoproteins. In the present study, fingertip blood and plasma levels of n-3 fatty acids, both at steady state or after a large intake (12 g of LC-FA as ethyl esters) were correlated to the levels of the major lipoproteins. At steady state there were weak, mainly non-significant correlations between n-3 levels and lipoproteins. However, the correlations became significantly negative between HDL-C levels and peak levels of n-3 or area under the curve after a single large intake of n-3 ethyl esters. These findings may shed light on recent observations indicating that exposure to n-3 can significantly decrease apoA-I, ABCA1, lecithin cholesterol acyltransferase and phospholipid transfer protein mRNA levels and antagonise A-I promoter activity.

Types of Fish Consumed and Fish Preparation Methods in Relation to Pancreatic Cancer Incidence: The VITAL Cohort Study

The associations of types of fish and fish preparation methods with pancreatic cancer risk remain unknown. The authors conducted a prospective cohort study in western Washington State among 66,616 adults, aged 50-76 years, who participated in the VITamins And Lifestyle cohort study. Diet was assessed by a food frequency questionnaire. Pancreatic cancer cases were identified by linkage to the Surveillance, Epidemiology, and End Results cancer registry. During an average follow-up of 6.8 years, 151 participants developed pancreatic cancer (adenocarcinoma). Long-chain (n-3) polyunsaturated fatty acids (LC-PUFAs) and nonfried fish intake were inversely associated with pancreatic cancer incidence. When the highest and lowest tertiles of exposure were compared, the multivariable-adjusted hazard ratio of pancreatic cancer was 0.62 (95% confidence interval: 0.40, 0.98) (P(trend) = 0.08) for LC-PUFAs and 0.55 (95% confidence interval: 0.34, 0.88) (P(trend) = 0.045) for nonfried fish. Docosahexaenoic acid showed a greater inverse association with pancreatic cancer than eicosapentaenoic acid. No statistically significant associations were observed with fried fish and shellfish consumption. The potential health impact of fish consumption may depend on the types of fish consumed and fish preparation methods. LC-PUFAs, particularly docosahexaenoic acid, and nonfried fish, but not shellfish or fried fish, may be beneficial in the primary prevention of pancreatic cancer.

Fish or Long-Chain (n-3) PUFA Intake Is Not Associated with Pancreatic Cancer Risk in a Meta-Analysis and Systematic Review1–3

Long-chain (n-3) PUFA (LC-PUFA) have been hypothesized to be beneficial in preventing pancreatic carcinogenesis, but the associations of fish or LC-PUFA intake with pancreatic cancer found in epidemiologic studies have been controversial and inconclusive. To estimate the overall association of LC-PUFA or fish intake with pancreatic cancer, we performed a systematic literature search of English-language articles using PubMed and EMBASE through February 2012 and reviewed the reference lists from retrieved articles. Prospective cohort or case-control studies that reported ratio estimates and corresponding 95% CI for the associations of fish or LC-PUFA intake and pancreatic cancer were selected. Independent data extraction was performed by 2 of the authors. The pooled associations were obtained by using a random-effects model. A database was derived from 9 independent cohorts that included 1,209,265 participants (3082 events) with a mean follow-up of 9 y and 10 independent case-control studies that included 2514 cases and 18,779 controls. Compared with those having the lowest fish consumption, the pooled RR of pancreatic cancer was 0.98 (95% CI: 0.86, 1.12) for those who had the highest fish intake from 8 cohort studies and was 0.96 (95% CI: 0.76, 1.21) from 9 case-control studies. We found similar results for LC-PUFA intake by combining data from 4 cohorts or 2 case-control studies. Our results do not support an overall inverse association of fish or LC-PUFA intake with risk of pancreatic cancer. Further studies that consider different species and preparation methods of fish, and additional adjustment for contaminants in fish, are warranted.

Fish oil positively regulates anabolic signalling alongside an increase in whole-body gluconeogenesis in ageing skeletal muscle

Fish oil, containing mainly long-chain n-3 polyunsaturated fatty acids (LCn-3PUFA), has been found to acutely stimulate protein synthesis and insulin-mediated glucose metabolism. However, the underlying mechanism and more prolonged effect of fish oil during ageing remain to be determined. Fish oil (EPAX6000; 49.6 % eicosapentaenoic acid, 50.4 % docosahexaenoic acid) or control oil (60 % olive, 40 % soy) supplementation was delivered, via chocolate-derived sweets, to rats for 8 weeks. Throughout the study, food intake and body weight were recorded and body composition was investigated using EchoMRI. During the last 40 min of a 6 h infusion, with labelled dextrose ([U-(13)C]glucose) and amino acids ([1-(13)C]phenylalanine), blood samples were collected to assess glucose and phenylalanine kinetics. Soleus and longissimus dorsi muscles were extracted for protein and mRNA analyses. Fish oil had no effect on food intake or body composition. An increased whole-body glucose turnover, mainly accounted for via an increase in endogenous glucose production, was observed with fish oil feeding. No effects on whole-body phenylalanine turnover were observed. In longissimus dorsi, fish oil augmented the phosphorylation of phosphoinositide 3-kinase (PI3K)([Tyr458]) (P = 0.04) and 70 kDa ribosomal protein S6 kinase (p70s6k)([Thr389]) (P = 0.04). There were no differences in protein kinase B (Akt)([Ser473]), mammalian target of rapamycin (mTOR)([Ser2448]), protein phosphatase 2A (PP2A) 56 kDa regulatory B subunit γ (PP2A-B56-γ), forkhead box containing proteins O-subclass 3a (FOX03a)([Ser253]) or inflammatory markers (Interleukin-6, Interleukin-1 β, tumour necrosis factor-α, and cyclooxygenase-2). Our data suggest that the fish oil may stimulate endogenous glucose production and increase anabolic signalling in ageing rats.

Dietary supplementation withn-3 PUFA does not promote weight loss when combined with a very-low-energy diet

Obesity is associated with elevated levels of inflammation and metabolic abnormalities which are linked to CVD. The aim of the present study was to investigate whether long-chain n-3 PUFA (LCn-3PUFA), combined with a very-low-energy diet (VLED), facilitated weight loss and weight maintenance, and improvements in blood lipids and inflammatory mediators. This was a double-blind, randomised, controlled trial with two parallel groups. For 14 weeks, one group consumed 6 × 1 g capsules/d of monounsaturated oil (placebo group, PB), and the other group consumed 6 × 1 g capsules/d of LCn-3PUFA (fish oil group, FO), each comprising 70 mg EPA and 270 mg DHA. Both groups were on VLED for 4 weeks (n 14 PB, n 18 FO), which was then followed by 10 weeks of weight maintenance (n 12 PB, n 17 FO). Fasting blood samples, anthropometric measurements and 3 d food diaries were collected at baseline, at 4 and 14 weeks. A greater-than-2-fold increase occurred in plasma levels of EPA and DHA in the FO group (P < 0·001). At 4 weeks, the mean weight loss was -6·54 (SD 2·08) kg (-6·9%) for PB and -6·87 (SD 1·83) kg (-7·7%) for FO. At week 14, after the maintenance phase, there was a further mean decrease in weight, -1·57 (SD 3·7) kg (1·85%) for PB and -1·69 (SD 2·32) kg (-1·9%) for FO. Both groups experienced improved metabolic profiles and there was a significant reduction in fat mass for the FO group at week 14 but not for PB. However, it would appear that supplementation with LCn-3PUFA had no significant effect on weight loss or weight maintenance over the 14 weeks.

Fish, n-3 Fatty Acids, and Cardiovascular Diseases in Women of Reproductive Age

Previous studies have indicated a protective effect of long-chain n-3 polyunsaturated fatty acids (LCn3FAs) against cardiovascular disease; however, women are underrepresented in cardiovascular research. The aim of this study was to explore the association between intake of LCn3FAs and the risk of cardiovascular disease in a large prospective cohort of young women (mean age at baseline: 29.9 years [range: 15.7-46.9]). Exposure information on 48 627 women from the Danish National Birth Cohort was linked to the Danish National Patients Registry for information on events of hypertensive, cerebrovascular, and ischemic heart disease used to define a combined measure of cardiovascular diseases. Intake of fish and LCn3FAs was assessed by a food-frequency questionnaire and telephone interviews. During follow-up (1996-2008; median: 8 years), 577 events of cardiovascular disease were identified. Low LCn3FA intake was associated with an increased risk of cardiovascular disease (adjusted hazard ratio for women in lowest versus highest LCn3FA intake group: 1.91 [95% CI: 1.26-2.90]). Restricting the sample to women who had consistently reported similar frequencies of fish intake across 3 different dietary assessment occasions tended to strengthen the relationship (hazard ratio for lowest versus highest intake: 2.91 [95% CI: 1.45-5.85]). Furthermore, the observed associations were consistent in supplementary analyses where LCn3FA intake was averaged across the 3 dietary assessment occasions, and the associations were persistent for all 3 of the individual outcomes. Our findings based on a large prospective cohort of relatively young and initially healthy women indicated that little or no intake of fish and LCn3FAs was associated with an increased risk of cardiovascular disease.

Growth, flesh adiposity and fatty acid composition of Atlantic salmon ( Salmo salar) families with contrasting flesh adiposity: Effects of replacement of dietary fish oil with vegetable oils

The present study compared the effects of diets formulated with reduced fishmeal (FM) content and either 100% fish oil (FO) or 100% of a vegetable oil (VO) blend in post-smolts of three family groups of Atlantic salmon. Two groups were selected as being either “Lean” or “Fat” based on estimated breeding values (EBV) for flesh adiposity of their parents derived from a breeding programme, while the third group (CAL) was a mix of non-pedigreed commercial families unrelated to the two groups above. The VO blend comprised rapeseed, palm and a new product, Camelina oil in a ratio of 5/3/2, and diets were fed to duplicate pens of each salmon group. After an ongrowing period of 55 weeks, to reach a mean weight of 3 kg, the fish from all treatments were switched to a decontaminated FO for a further 24 weeks to follow restoration of long-chain n−3 polyunsaturated fatty acids (LC-PUFA) in the fish previously fed VO. Final weights were significantly affected by family group and there was also an interaction between diet and group with Fat and Lean FO fish being larger than the same fish fed VO. Specific growth rate (SGR) was highest in CAL fish (1.01), feed conversion ratio (FCR) was highest in the Lean fish but there were no significant effects on thermal growth coefficient (TGC). Condition Factor (CF) was lowest in CAL fish while the hepato-somatic index (HSI) was highest in Lean fish and viscero-somatic index (VSI) highest in Fat fish. Flesh and viscera lipid content was affected by both family group and diet with a significant interaction between the two. Flesh lipid in fish fed FO was in the order Fat > CAL > Lean although this order was Fat = Lean > CAL when fed VO. Flesh fatty acid compositions were affected mainly by diet although some minor fatty acids were also influenced by group. Fish fed VO had n−3 LC-PUFA reduced by ∼ 65% compared to fish fed FO but this could be restored by a 16-week FO finishing diet phase. The differences observed in lipid and fatty acid deposition suggested that genetics affected lipid deposition and metabolism and that breeding programmes could select for fish that retained more n−3 LC-PUFA in their flesh, particularly when fed diets low in these fatty acids.

Docosahexaenoic acid, but not eicosapentaenoic acid, lowers ambulatory blood pressure and shortens interval QT in spontaneously hypertensive rats in vivo

This study was designed to evaluate the effects of individual dietary long-chain n-3 polyunsaturated fatty acids (LCPUFA) on hypertension and cardiac consecutive disorders in spontaneously hypertensive rats (SHR) as compared to Wistar-Kyoto rats (WKY). Rats were fed for 2 months an eicosapentaenoic (EPA)- or docosahexaenoic acid (DHA)-rich diet (240 mg/day) or an n-3 PUFA-free diet. Male SHR ( n=6), implanted with cardiovascular telemetry devices, were housed in individual cages for continuous measurements of cardiovascular parameters (blood pressure (BP) and heart rate (HR)) during either activity or rest periods, ECG were recorded during the quiet period. The n-6 PUFA upstream of arachidonic acid was affected in SHR tissues. The cardiac phospholipid fatty acid profile was significantly affected by dietary DHA supply, and EPA in a very lower extent, since DHA only was incorporated in the membranes instead of n-6 PUFAs. Endothelium n-6 PUFA content increased in all SHR groups. Compared to WKY, linoleic acid content decreased in both studied tissues. Cardiac noradrenalin decreased while the adrenal catecholamine stores decreased in SHR as compared to WKY. Both n-3 PUFA supply induced a decrease of adrenal catecholamine stores. Nevertheless after 6 weeks, DHA but not EPA induced a lowering-blood pressure effect and shortened the QT interval in SHR, most probably through its tissue enrichment and a specific effect on adrenergic function. Dietary DHA supply retards blood pressure development and has cardioprotective effect. These findings, showing the cardioprotective effects of DHA in living animals, were obtained in SHR, but may relate to essential hypertension in humans.

Long‐chain n‐3 fatty acids – New anabolic compounds improving protein metabolism

Previous animal studies demonstrated that chronic feeding of long‐chain n‐3 polyunsaturated fatty acids (LCn‐3PUFA) that modifies muscle membrane fatty acid composition promotes protein anabolism by blunting the age‐associated deterioration in insulin sensitivity. The current study assessed, as a proof of concept, the anabolic effects of LCn‐3PUFA‐rich menhaden oil in 78 male castrated pigs (20 kg initial body weight). Pigs were fed for 76 days diets containing 0, 3, or 4% menhaden oil using iso‐energetic oil substitutions in diets typical of swine production (6% fat matter). Performance and body composition were measured using ultrasound technology during growth at 55 and 85 kg according to a complete block design. Menhaden oil feeding linearly reduced feed intake with a decline from 2.58 to 2.51 kg/d (‐3%; P=0.04) at 85 kg body weight without altering body weight gain. Back fat thickness remained unchanged (11.16 mm) between treatments. The diameter of the longissimus dorsi was linearly increased as menhaden oil amount increased (50.0, 50.1, 51.8 mm; P=0.02). The results demonstrate for the first time that LCn‐3PUFA promote muscle protein accretion, this approach could be a novel intervention to ameliorate the age‐related loss of muscle mass in the human.

SUPPLEMENTATION OF LONG CHAIN N‐3 POLYUNSATURATED FATTY ACIDS INCREASES THE UTILIZATION OF LYCOPENE IN CULTURED AIRWAY EPITHELIAL CELLS

ABSTRACT Increased content of long chain n‐3 polyunsaturated fatty acids (LCn‐3PUFA) in cellular membranes results in increased susceptibility to lipid peroxidation. Antioxidants such as lycopene prevent lipid peroxidation and oxidative degradation. The aim of this study was to determine the effects of LCn‐3PUFA supplementation on lycopene levels in cultured airway epithelial cells. Airway epithelial cells (Calu‐3) were incubated with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), lycopene‐DHA and lycopene‐EPA for 24 h. The fatty acid incorporation into the cells was analyzed using gas chromatography. Intracellular lycopene concentration was determined using high‐performance liquid chromatography. It was found that EPA (10.6%) and DHA (19.5%) were incorporated into Calu‐3 cells. It was also found that increased incorporation of DHA (and to a lesser extent EPA) resulted in decreased intracellular lycopene levels. These findings suggest that supplementation with LCn‐3PUFA increases the cellular need for antioxidants. PRACTICAL APPLICATIONSIncreasing the proportion of long chain n‐3 polyunsaturated fatty acids (LCn‐3PUFA) in airway cell membranes leads to increased utilization of a potent antioxidant, lycopene. This increased utilization of lycopene is probably due to the increased susceptibility of LCn‐3PUFA to oxidative damage. The interaction between lycopene and LCn‐3PUFA has important implications for both in vivo and in vitro models of respiratory diseases and suggests that co‐supplementation of antioxidants with LCn‐3PUFA is essential to maximize any potential anti‐inflammatory effect.

Anti-inflammatory effects of long-chainn-3 PUFA in rhinovirus-infected cultured airway epithelial cells

Long-chain n-3 PUFA (LCn-3PUFA) including DHA and EPA, are known to decrease inflammation by inhibiting arachidonic acid (AA) metabolism to eicosanoids, decreasing the production of pro-inflammatory cytokines and reducing immune cell function. The aim of this study was to determine if EPA and DHA reduced the release of inflammatory mediators from airway epithelial cells infected with rhinovirus (RV). Airway epithelial cells (Calu-3) were incubated with EPA, DHA and AA for 24 h, followed by rhinovirus infection for 48 h. IL-6, IL-8 and interferon-gamma-induced protein-10 (IP-10) released by cells were measured using ELISA. Viral replication was measured by serial titration assays. The fatty acid content of cells was analysed using GC. Cellular viability was determined by visual inspection of cells and lactate dehydrogenase release. DHA (400 microm) resulted in a significant 16% reduction in IL-6 release after RV-43 infection, 29% reduction in IL-6 release after RV-1B infection, 28% reduction in IP-10 release after RV-43 infection and 23 % reduction in IP-10 release after RV-1B infection. Cellular DHA content negatively correlated with IL-6 and IP-10 release. None of the fatty acids significantly modified rhinovirus replication. DHA supplementation resulted in increased cellular content of DHA at the cost of AA, which may explain the decreased inflammatory response of cells. EPA and AA did not change the release of inflammatory biomarkers significantly. It is concluded that DHA has a potential role in suppressing RV-induced airway inflammation.

Long-chain n-3 fatty acids enhance neonatal insulin-regulated protein metabolism in piglets by differentially altering muscle lipid composition

This study investigated the role of long-chain n-3 polyunsaturated fatty acids (LCn-3PUFAs) of muscle phospholipids in the regulation of neonatal metabolism. Twenty-eight piglets were weaned at 2 days of age and raised on one of two milk formulas that consisted of either a control formula supplying 0% or a formula containing 3.5% LCn-3PUFAs until 10 or 28 days of age. There was a developmental decline in the insulin sensitivity of amino acid disposal in control pigs during the first month of life, with a slope of -2.24 micromol.kg(-1).h(-1) (P = 0.01) per unit of insulin increment, as assessed using hyperinsulinemic-euglycemic-euaminoacidemic clamps. LCn-3PUFA feeding blunted this developmental decline, resulting in differing insulin sensitivities (P < 0.001). When protein metabolism was assessed under parenteral feeding-induced hyperinsulinemia, LCn-3PUFAs reduced by 16% whole body oxidative losses of amino acids (from 238 to 231 micromol.kg(-1).h(-1); P = 0.06), allowing 41% more amino acids to accrete into body proteins (from 90 to 127 micromol.kg(-1).h(-1); P = 0.06). The fractional synthetic rate of muscle mixed proteins remained unaltered by the LCn-3PUFA feeding. However, LCn-3PUFAs retarded a developmental increase in the essential-to-nonessential amino acid ratio of the muscle intracellular free pool (P = 0.05). Overall, alterations in metabolism were concomitant with a preferential incorporation of LCn-3PUFAs into muscle total membrane phospholipids (P < 0.001), in contrast to intramuscular triglycerides. These results underscore the potential role of LCn-3PUFAs as regulators of different aspects of protein metabolism in the neonate.

Consumption of an n-3 polyunsaturated fatty acid-enriched dip modulates plasma lipid profile in subjects with diabetes type II

Recent developments in micro-emulsification technology have allowed the fortification of foods with long-chain n-3 polyunsaturated fatty acid (PUFA) without the undesirable fish odour/taste and with reasonable shelf life. The effects of supplementing the diets of people with diabetes type II with a hummus-based dip enriched with long-chain n-3PUFA on plasma fatty acid composition and lipid levels were examined. A pre- and post-intervention study. This study was conducted at the University of Newcastle, Australia. Participants were recruited via advertisements on the University of Newcastle notice boards and in the local newspapers. Following initial response to study advertisements, information statements were mailed out to 29 potential participants. Thirteen participants were eligible and consented to participate in the trial. There were no dropouts as all the 13 participants completed 6-week intervention trial. Free-living male and female subjects with diabetes type II (n=13) consumed the n-3PUFA-enriched dip for a period of 6 weeks. Fasting blood samples were collected pre- and post-intervention for analyses of fatty acids and plasma lipids. Following 6 weeks of consuming the enriched dip, all the long-chain n-3PUFA (20:5n-3, 22:5n-3 and 22:6n-3) were significantly (P<0.05) elevated in the plasma lipids. This represented an increase in 20:5n-3 content by 117%, an increase in 22:5n-3 content by 15% and an increase in 22:6n-3 content by 80% over the baseline values before dip consumption. A significant reduction (P<0.05) in the plasma triglyceride levels from 1.93 (1.08-2.09) mmol/l at baseline to 1.27 (0.93-2.22) mmol/l after 6 weeks was also apparent following the consumption of the n-3PUFA-enriched dip. Plasma cholesterol was unchanged; however, low-density lipoprotein (LDL)-cholesterol (2.46+/-0.21 versus 2.72+/-0.22 mmol/l, P<0.034) and high-density lipoprotein (HDL)-cholesterol (1.16+/-0.09 versus 1.22+/-0.09 mmol/l, P<0.042) were significantly increased following the dietary intervention. These results demonstrate that n-3PUFA are readily bioavailable from the fortified dip matrix and alter the plasma lipid profile.