Comparison of the effects of linseed oil and different doses of fish oil on mononuclear cell function in healthy human subjects

The effects of omega-3 fatty acids supplementation on hemoglobin, hematocrit, and platelet levels of patients with ESRD condition undergoing dialysis

Background

Concomitant inflammation may boost the cardiovascular complications in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD). Omega-3 fatty acids may have certain health benefits in HD patients. The aim of this study was to investigate the effects of omega-3 fatty acids supplementation on hematocrit (HCT), hemoglobin (HB) level and platelet (PLT) counts of HD patients.

Methods

A randomized controlled trial was conducted on HD patients at a private dialysis center in Rasht, Iran. Three omega-3 fatty acid supplement capsules (3 g/d) were administered daily for two months to patients in the intervention group (n = 55). The control group (n = 60) were given three placebo capsules containing medium chain triglyceride (MCT) oil, similar to the supplemental dose of the intervention group at the same period. Three parameters of HCT, HB and PLT were measured at baseline and after the intervention.

Results

The PLT count decreased in the intervention group compared to the control group (173.38 ± 74.76 vs. 227.68 ± 86.58 103/mm3, F = 4.83, P = 0.03). No significant change was found on the levels of HCT and HB parameters between the two groups after the intervention.

Conclusion

Omega-3 supplementation in HD patients may decrease the risk of forming blood clots in the blood vessels. Further studies are warranted.

Analysis of omega-3 and omega-6 polyunsaturated fatty acid metabolism by compound-specific isotope analysis in humans

Natural variations in the 13C:12C ratio (carbon-13 isotopic abundance [δ13C]) of the food supply have been used to determine the dietary origin and metabolism of fatty acids, especially in the n-3 PUFA biosynthesis pathway. However, n-6 PUFA metabolism following linoleic acid (LNA) intake remains under investigation. Here, we sought to use natural variations in the δ13C signature of dietary oils and fatty fish to analyze n-3 and n-6 PUFA metabolism following dietary changes in LNA and eicosapentaenoic acid (EPA) + DHA in adult humans. Participants with migraine (aged 38.6 ± 2.3 years, 93% female, body mass index of 27.0 ± 1.1 kg/m2) were randomly assigned to one of three dietary groups for 16 weeks: 1) low omega-3, high omega-6 (H6), 2) high omega-3, high omega-6 (H3H6), or 3) high omega-3, low omega-6 (H3). Blood was collected at baseline, 4, 10, and 16 weeks. Plasma PUFA concentrations and δ13C were determined. The H6 intervention exhibited increases in plasma LNA δ13C signature over time; meanwhile, plasma LNA concentrations were unchanged. No changes in plasma arachidonic acid δ13C or concentration were observed. Participants on the H3H6 and H3 interventions demonstrated increases in plasma EPA and DHA concentration over time. Plasma δ13C-EPA increased in total lipids of the H3 group and phospholipids of the H3H6 group compared with baseline. Compound-specific isotope analysis supports a tracer-free technique that can track metabolism of dietary fatty acids in humans, provided that the isotopic signature of the dietary source is sufficiently different from plasma δ13C.

A comprehensive review of the health benefits of flaxseed oil in relation to its chemical composition and comparison with other omega-3-rich oils

Flaxseed (Linum usitatissimum L) is an ancient perennial plant species regarded as a multipurpose plant owing to its richness in omega-3 polyunsaturated fatty acids (PUFA) including α-linolenic acid (ALA). The extensive biochemical analysis of flaxseed resulted in the identification of its bioactive, i.e., lignans with potential application in the improvement of human health. Flaxseed oil, fibers, and lignans exert potential health benefits including reduction of cardiovascular disease, atherosclerosis, diabetes, cancer, arthritis, osteoporosis, and autoimmune and neurological disorders that have led to the diversification of flaxseed plant applications. This comprehensive review focuses on flaxseed oil as the major product of flaxseed with emphasis on the interrelationship between its chemical composition and biological effects. Effects reviewed include antioxidant, anti-inflammatory, antimicrobial, anticancer, antiulcer, anti-osteoporotic, cardioprotective, metabolic, and neuroprotective. This study provides an overview of flaxseed oil effects with the reported action mechanisms related to its phytochemical composition and in comparison, to other PUFA-rich oils. This study presents the most updated and comprehensive review summarizing flaxseed oil's health benefits for the treatment of various diseases.

Long Chain Polyunsaturated Fatty Acids Docosahexaenoic Acid and Arachidonic Acid Supplementation in the Suckling and the Post-weaning Diet Influences the Immune System Development of T Helper Type-2 Bias Brown Norway Rat Offspring

Background: Dietary long chain polyunsaturated fatty acids (LCPUFA) such as arachidonic acid (ARA) and docosahexaenoic acid (DHA) play an important role in the development of the infant immune system. The role of LCPUFA in the T helper type 2 (Th2) biased immune system is unknown. We aimed to understand the effect of feeding LCPUFA during suckling and post-weaning on immune system development in Th2 bias Brown Norway rat offspring.

Methods: Brown Norway dams were randomly assigned to nutritionally adequate maternal diet throughout the suckling period (0–3 weeks), namely, control diet (0% ARA, 0% DHA; n= 8) or ARA + DHA (0.45% ARA, 0.8% DHA; n = 10). At 3 weeks, offspring from each maternal diet group were randomized to either a control (0% ARA, 0% DHA; n = 19) or ARA+DHA post-weaning (0.5% ARA, 0.5% DHA; n = 18) diet. At 8 weeks, offspring were killed, and tissues were collected for immune cell function and fatty acid composition analyses.

Results: ARA + DHA maternal diet resulted in higher (p < 0.05) DHA composition in breast milk (4×) without changing ARA levels. This resulted in more mature adaptive immune cells in spleen [T regulatory (Treg) cells and B cells], mesenteric lymph nodes (MLN, lower CD45RA+), and Peyer's patches (PP; higher IgG+, B cells) in the ARA+DHA group offspring at 8 weeks. ARA+DHA post-weaning diet (3–8 weeks) resulted in 2 × higher DHA in splenocyte phospholipids compared to control. This also resulted in higher Th1 cytokines, ~50% higher TNF-α and IFNγ, by PMAi stimulated splenocytes ex vivo, with no differences in Th2 cytokines (IL-4, IL-13, and IL-10) compared to controls.

Conclusion: Feeding dams a diet higher in DHA during the suckling period resulted in adaptive immune cell maturation in offspring at 8 weeks. Providing ARA and DHA during the post-weaning period in a Th2 biased Brown Norway offspring model may support Th1 biased immune response development, which could be associated with a lower risk of developing atopic diseases.

Effects of Flaxseed on Blood Lipids in Healthy and Dyslipidemic Subjects: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

To address hyperlipidemia, flaxseed demonstrates a great impact on experimental and clinical trials. Therefore, the effects of flaxseed on lipid profiles of healthy and dyslipidemic subjects were assayed. The literature search was performed based on English reports of randomized control trials (RCTs) up to April 2021 to seek the effect of flaxseed on lipid profiles of healthy and dyslipidemic subjects. A total of 14 RCTs with 1107 participants were evaluated. Based on results, flaxseed significantly improves the lipid profile in dyslipidemic patients comprising total cholesterol (TC), low-density lipoprotein (LDL-C) and triglyceride (TG) in comparison with the control group. Nevertheless, no significant changes were observed in high-density lipoprotein (HDL-C). Although in healthy individual flaxseed significantly increased HDL-C, LDL-C and TG. Subgroup analysis on healthy subjects showed that flaxseed improved LDL-C on overweight subjects with BMI>25. The evidence suggests that flaxseed significantly improved TC, LDL-C and TG in dyslipidemic subjects and additionally improved the HDL-C on healthy subjects.

In the Age of Viral Pandemic, Can Ingredients Inspired by Human Milk and Infant Nutrition Be Repurposed to Support the Immune System?

In 2020, with the advent of a pandemic touching all aspects of global life, there is a renewed interest in nutrition solutions to support the immune system. Infants are vulnerable to infection and breastfeeding has been demonstrated to provide protection. As such, human milk is a great model for sources of functional nutrition ingredients, which may play direct roles in protection against viral diseases. This review aims to summarize the literature around human milk (lactoferrin, milk fat globule membrane, osteopontin, glycerol monolaurate and human milk oligosaccharides) and infant nutrition (polyunsaturated fatty acids, probiotics and postbiotics) inspired ingredients for support against viral infections and the immune system more broadly. We believe that the application of these ingredients can span across all life stages and thus apply to both pediatric and adult nutrition. We highlight the opportunities for further research in this field to help provide tangible nutrition solutions to support one's immune system and fight against infections.

Effect of Omega-3 on Recurrent Aphthous Stomatitis and Improvement Quality of Life

Objective

Recurrent aphthous stomatitis is one of the most common chronic inflammatory diseases in oral mucosa. Beneficial effects of omega-3 supplements on some inflammatory diseases have been proved. The aim of present study was to evaluate the effect of omega-3 supplements in recurrent aphthous stomatitis management and improve oral health-related quality of life.

Methods

In this double-blind clinical trial, 40 patients with minor recurrent aphthous stomatitis were randomly divided into case and control groups. The case group received 1000 mg capsules of omega-3, while the control group received placebo capsules for 6 months. The questionnaires of the ulcer severity score and the chronic oral mucosal disease questionnaire were filled by the patients in three steps, at the baseline session, after 3 months, and after 6 months. The data were analyzed by SPSS 22 software through ANOVA, Mann-Whitney, and chi-square tests. P < 0.05 was considered as significant.

Results

In the omega-3 group, the ulcer severity score showed significant reduction by three-month and six-month follow-ups (P < 0.0001, P < 0.0001, respectively). The mean score of the chronic oral mucosal disease questionnaire significantly improved by three-month and six-month follow-ups in the omega-3-receiving group.

Conclusion

Use of omega-3 oral supplements decreased the severity of aphthous ulcer and improved oral health-related quality of life.

The effects of low-ratio n-6/n-3 PUFA on biomarkers of inflammation: a systematic review and meta-analysis

OBJECTIVE

The purpose of the systematic review and meta-analysis was to determine if low-ratio n-6/n-3 long-chain polyunsaturated fatty acid (PUFA) supplementation affects serum inflammation markers based on the current studies.

METHODS

PubMed, Embase and The Cochrane library databases were systematically searched to find randomized controlled trials (RCTs) on the effect of low-ratio n-6/n-3 PUFA intervention on inflammation markers up to July 2020. Data were pooled using standardized mean difference (SMD) and 95% confidence intervals (95% CI), with P value ≦ 0.05 as statistical significance.

RESULTS

Thirty-one RCTs were included in the meta-analysis. The analysis indicated that increasing low-ratio n-6/n-3 PUFA supplementation decreased the level of tumor necrosis factor-α (TNF-α) (SMD = -0.270; 95% CI: -0.433, -0.106; P = 0.001) and interleukin 6 (IL-6) (SMD = -0.153; 95% CI: -0.260, -0.045; P = 0.005). There were no significant effects on C-reactive protein (CRP) (SMD = -0.027; 95% CI: -0.189: 0.135; P = 0.741). Subgroup analysis indicated that there was a significant reduction in TNF-α serum concentration in subjects from Asia (SMD: -0.367; 95% CI: -0.579, -0.155; P = 0.001) and in subjects with diseases (SMD: -0.281; 95% CI: -0.436, -0.127; P < 0.001). In the subgroup of the n-6/n-3 ratio ≦5, low-ratio n-6/n-3 PUFA supplementation could decrease the level of TNF-α (SMD: -0.335; 95% CI: -0.552, -0.119; P = 0.002). Serum IL-6 decreased significantly in patients from the Europe subgroup (SMD: -0.451; 95% CI: -0.688, -0.214; P < 0.001), but not in Asia (SMD: -0.034; 95% CI: -0.226, 0.157; P = 0.724), North America (SMD: -0.115; 95% CI: -0.274, 0.044; P = 0.157) and Oceania (SMD: 0.142; 95% CI: -0.557, 0.842; P = 0.690).

CONCLUSION

Low-ratio n-6/n-3 PUFA supplementation could decrease significantly the concentration of serum TNF-α and IL-6, but not decrease CRP concentration.

Effect of flaxseed oil supplementation on the erythrocyte membrane fatty acid composition and endocannabinoid system modulation in patients with coronary artery disease: a double-blind randomized controlled trial

Background

The endocannabinoid system (ECS) overactivation, associated with increased inflammatory process, may act as a risk factor for coronary artery disease (CAD). Dietary fat may influence the ECS tone. The aim of the present study was to investigate the effect of flaxseed oil on the erythrocyte membrane fatty acid profile and ECS activity by the measurement of serum N-arachydonoil ethanolamine (AEA) and cannabinoid receptor type-1 (CB1), cannabinoid receptor type-2 (CB2), and fatty acid amide hydrolase (FAAH) mRNA expression.

Methods

This clinical trial was performed on 44 patients with CAD. The intervention group received 1.5% fat milk supplemented with flaxseed oil (containing 2.5 g α-linolenic acid or ALA), while the placebo group received 1.5% fat milk for 10 weeks. The fatty acid profile of erythrocyte membrane phospholipids was measured by gas chromatography. The AEA level was determined using an ELISA kit, and real-time PCR was performed to measure CB1, CB2, and FAAH mRNA expression pre- and post-intervention.

Results

Flaxseed oil supplementation resulted in a significant increase in the ALA content and a significant reduction in linoleic acid (LA) content of membrane phospholipids, compared to the placebo group (MD = − 0.35 and 2.89, respectively; P < 0.05). The within group analysis showed that flaxseed oil supplementation caused a significant reduction in both LA and arachidonic acid (MD = − 4.84 and − 4.03, respectively; P < 0.05) and an elevation in the ALA (MD = 0.37, P < 0.001) content of membrane phospholipids compared with the baseline. In the intervention group, a marked reduction was observed in the serum AEA level after 10 weeks of intervention, compared with the placebo group (MD = 0.64, P = 0.016). Changes in CB2 mRNA expression in the flaxseed oil group were significant (fold change = 1.30, P = 0.003), compared with the placebo group.

Conclusion

Flaxseed oil supplementation could attenuate the ECS tone by decreasing the AEA level and increasing CB2 mRNA expression. Therefore, flaxseed oil may be considered a promising agent with cardioprotective properties.

Effect of Free Fatty Acids on Inflammatory Gene Expression and Hydrogen Peroxide Production by Ex Vivo Blood Mononuclear Cells

The aim of this study was to assess free fatty acids’ (FAs) ex vivo anti-/proinflammatory capabilities and their influence on inflammatory gene expression and H₂O₂ production by human peripheral blood mononuclear cells (PBMCs). Anthropometric and clinical measurements were performed in 26 participants with metabolic syndrome. Isolated PBMCs were incubated ex vivo for 2 h with several free fatty acids—palmitic, oleic, α-linolenic, γ-linolenic, arachidonic and docosahexaenoic at 50 μM, and lipopolysaccharide (LPS) alone or in combination. H₂O₂ production and IL6, NFκB, TLR2, TNFα, and COX-2 gene expressions were determined. Palmitic, γ-linolenic, and arachidonic acids showed minor effects on inflammatory gene expression, whereas oleic, α-linolenic, and docosahexaenoic acids reduced proinflammatory gene expression in LPS-stimulated PBMCs. Arachidonic and α-linolenic acids treatment enhanced LPS-stimulated H₂O₂ production by PBMCs, while palmitic, oleic, γ-linolenic, and docosahexaenoic acids did not exert significant effects. Oleic, α-linolenic, and docosahexaenoic acids induced anti-inflammatory responses in PBMCs. Arachidonic and α-linolenic acids enhanced the oxidative status of LPS-stimulated PBMCs. In conclusion, PBMC ex vivo assays are useful to assess the anti-/proinflammatory and redox-modulatory effects of fatty acids or other food bioactive compounds.

Biomarkers of meat and seafood intake: an extensive literature review

Meat, including fish and shellfish, represents a valuable constituent of most balanced diets. Consumption of different types of meat and fish has been associated with both beneficial and adverse health effects. While white meats and fish are generally associated with positive health outcomes, red and especially processed meats have been associated with colorectal cancer and other diseases. The contribution of these foods to the development or prevention of chronic diseases is still not fully elucidated. One of the main problems is the difficulty in properly evaluating meat intake, as the existing self-reporting tools for dietary assessment may be imprecise and therefore affected by systematic and random errors. Dietary biomarkers measured in biological fluids have been proposed as possible objective measurements of the actual intake of specific foods and as a support for classical assessment methods. Good biomarkers for meat intake should reflect total dietary intake of meat, independent of source or processing and should be able to differentiate meat consumption from that of other protein-rich foods; alternatively, meat intake biomarkers should be specific to each of the different meat sources (e.g., red vs. white; fish, bird, or mammal) and/or cooking methods. In this paper, we present a systematic investigation of the scientific literature while providing a comprehensive overview of the possible biomarker(s) for the intake of different types of meat, including fish and shellfish, and processed and heated meats according to published guidelines for biomarker reviews (BFIrev). The most promising biomarkers are further validated for their usefulness for dietary assessment by published validation criteria.

Effects of Flaxseed Interventions on Circulating Inflammatory Biomarkers: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

There have been various clinical studies on the effect of flaxseed-derived products on circulating inflammatory biomarkers, but the findings from these are contradictory. The aim of the present study was to clarify any association. A comprehensive literature search was conducted from inception to May 2018. From the eligible trials, 32 articles describing studies conducted on adults aged 18-70 y were selected for the meta-analysis. Meta-analyses using the random-effects model were performed to investigate the data and results showed significant effects of flaxseed intake on circulating high-sensitivity CRP (hs-CRP) [weighted mean difference (WMD) = -0.75; 95% CI: -1.19, -0.30; P < 0.001] and TNFα (WMD = -0.38; 95% CI: -0.75,-0.01; P = 0.04). However, no significant changes were found in IL6 concentration (WMD = -0.24; 95% CI: -0.70, 0.21; P = 0.28) and C-reactive protein (CRP) (WMD = -0.34; 95% CI:-0.89, 0.20; P = 0.22). Moreover, by eliminating 1 of the studies from the sensitivity analysis, changes in IL6 concentration were significant (WMD = -0.44; 95% CI: -0.81, -0.08). The changes in inflammatory biomarkers were dependent on study design (parallel or crossover), supplement type (flaxseed, flaxseed oil, or lignan), study quality (high or low), and participants' age and BMI. According to this meta-analysis, flaxseed significantly reduced circulating concentrations of hs-CRP and TNFα, but did not affect IL6 and CRP. Further research is needed to examine the effect of different doses and long-term benefits of flaxseed and its derivatives on inflammatory factors.

The effect of different sources of fish and camelina sativa oil on immune cell and adipose tissue mRNA expression in subjects with abnormal fasting glucose metabolism: a randomized controlled trial

Background/Objectives

Molecular mechanisms linking fish and vegetable oil intakes to their healthy metabolic effects may involve attenuation of inflammation. Our primary aim was to examine in a randomized controlled setting whether diets enriched in fatty fish (FF), lean fish (LF) or ALA-rich camelina sativa oil (CSO) differ in their effects on the mRNA expression response of selected inflammation-related genes in peripheral blood mononuclear cells (PBMCs) and subcutaneous adipose tissue (SAT) in subjects with impaired fasting glucose.

Subjects/Methods

Samples from 72 participants randomized to one of the following 12-week intervention groups, FF (n = 19), LF (n = 19), CSO (n = 17) or a control group (n = 17), were available for the PBMC study. For SAT, 39 samples (n = 8, n = 10, n = 9, n = 12, respectively) were available. The mRNA expression was measured at baseline and 12 weeks by TaqMan® Low Density Array.

Results

In PBMCs, LF decreased ICAM1 mRNA expression (P < 0.05), which was different (P = 0.06, Bonferroni correction) from the observed increase in the FF group (P < 0.05). Also, compared to the control group, LF decreased ICAM1 mRNA expression (P < 0.05). Moreover, the change in ICAM1 mRNA expression correlated positively with the intake of FF (P < 0.05) and negatively with the intake of LF (P < 0.05), independently of study group. A diet enriched in CSO, a rich source of alpha-linolenic acid (ALA), decreased PBMC IFNG mRNA expression (P < 0.01). The intake of CSO in the CSO group, but not the increase in plasma ALA proportions, correlated inversely with the IFNG mRNA expression in PBMCs (P = 0.08). In SAT, when compared with the control group, the effect of FF on decreasing IL1RN mRNA expression was significant (P < 0.03).

Conclusion

We propose that CSO intake may partly exert its benefits through immuno-inflammatory molecular regulation in PBMCs, while modulation of ICAM1 expression, an endothelial/vascular-related gene, may be more dependent on the type of fish consumed.

Validation of an equation predicting highly unsaturated fatty acid (HUFA) compositions of human blood fractions from dietary intakes of both HUFAs and their precursors

Proportions of omega-3 (n-3) and omega-6 (n-6) in 20- and 22-carbon highly unsaturated fatty acids with 3 or more double bonds (HUFA) accumulated in tissue HUFA (e.g., the %n-6 in HUFA) are biomarkers reflecting intakes of n-6 and n-3 fatty acids. An empirical equation, referred to here as the Lands' Equation, was developed previously to use dietary intakes of n-6 and n-3 HUFA and their 18-carbon precursors to estimate the %n-6 in HUFA of humans. From the PubMed database, we identified clinical trials reporting (a) dietary intake of at least linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3), and (b) the amounts of at least arachidonic acid (20:4n-6), eicosapentaenoic acid (20:5n-3), and docosahexaenoic acid (22:6n-3) in lipids of plasma, serum, or red blood cell. Linear regression analyses comparing reported and predicted %n-6 in HUFA gave a correlation coefficient of 0.73 (p<0.000000) for 34 studies with 92 subject groups. These results indicate that circulating HUFA compositions can be reliably estimated from dietary intake data that not only includes n-3 and n-6 HUFA consumption, but also includes consumption of 18 carbon n-3 and n-6 precursor fatty acids.

Effect of supplementation with flaxseed oil and different doses of fish oil for 2 weeks on plasma phosphatidylcholine fatty acids in young women

Background/objectives

Although assumed, it remains unclear that fatty acid (FA) biomarkers of n-3 long-chain PUFA reflect wide ranges of intake. However, to be utilised as biomarkers, to predict dietary intake, dose–response curves that cover a spectrum of intakes are required. The aim of the study was to investigate whether the FA composition of plasma phosphatidylcholine (PC) is a sensitive biomarker of n-3 FAs from fish oil, across a range of supplementation doses, and alpha-linolenic acid (ALA) supplementation, in young, healthy women.

Subjects/methods

A total of 303 young women were randomised to intakes ranging between 0.33 and 4.50 g EPA+DHA/day from fish oil (not all doses used in each year) or flaxseed oil (5.90–6.60 g/d) daily for 14 days in a series of trials, over 5 years. Fasting blood was collected at baseline (day 0) and day 14 and plasma PC FA composition, total and HDL-cholesterol and triglyceride concentrations measured.

Results

Fourteen days supplementation with fish oil significantly (P < 0.01) increased, in a dose-dependent fashion, plasma PC EPA, DPA and DHA at all doses except 1 and 3 mL/day. For the combined group of women who consumed any fish oil there was a 16% (P < 0.01) decrease in plasma triacylglycerol concentrations after 14 days supplementation. Flaxseed oil supplementation for 14 day resulted in significant (P < 0.01) increases in ALA, EPA and DPA, whilst DHA remained unchanged.

Conclusion

Our data demonstrate plasma PC is a sensitive biomarker of n-3 FA intake and reflects changes within 14 days across a range of intakes.

Dietary intervention and health in patients with systemic lupus erythematosus: A systematic review of the evidence

Objective: The aim of this study was to evaluate the scientific evidence of dietary intervention, either through diet or supplementation, and its effects on the health of patients with systemic lupus erythematosus. Methods: Literature searches were conducted using Scopus, PubMed, BioMed Central and Science Direct databases. The terms used for the search were diet, nutritional support, nutrition therapy and systemic lupus erythematosus. Results: Eleven studies with interventions related to supplementation of omega-3 fatty acids, vitamin D and turmeric, as well as changes in diet composition, such as low glycaemic index diet were identified. Conclusions: The studies evidenced that omega-3 supplementation reduced inflammation, disease activity, endothelial dysfunction and oxidative stress; vitamin D supplementation increased serum levels, reduced inflammatory and hemostatic markers; turmeric supplementation reduced proteinuria, hematuria and systolic blood pressure; and low glycaemic index diet caused weight loss and reduced fatigue.

Polyunsaturated Fatty Acid Biosynthesis Involving Δ8 Desaturation and Differential DNA Methylation of FADS2 Regulates Proliferation of Human Peripheral Blood Mononuclear Cells

Polyunsaturated fatty acids (PUFAs) are important for immune function. Limited evidence indicates that immune cell activation involves endogenous PUFA synthesis, but this has not been characterised. To address this, we measured metabolism of 18:3n-3 in quiescent and activated peripheral blood mononuclear cells (PBMCs), and in Jurkat T cell leukaemia. PBMCs from men and women (n = 34) were incubated with [1-¹³C]18:3n-3 with or without Concanavalin A (Con. A). 18:3n-3 conversion was undetectable in unstimulated PBMCs, but up-regulated when stimulated. The main products were 20:3n-3 and 20:4n-3, while 18:4n-3 was undetectable, suggesting initial elongation and Δ8 desaturation. PUFA synthesis was 17.4-fold greater in Jurkat cells than PBMCs. The major products of 18:3n-3 conversion in Jurkat cells were 20:4n-3, 20:5n-3, and 22:5n-3. ¹³C Enrichment of 18:4n-3 and 20:3n-3 suggests parallel initial elongation and Δ6 desaturation. The FADS2 inhibitor SC26196 reduced PBMC, but not Jurkat cell, proliferation suggesting PUFA synthesis is involved in regulating mitosis in PBMCs. Con. A stimulation increased FADS2, FADS1, ELOVL5 and ELOVL4 mRNA expression in PBMCs. A single transcript corresponding to the major isoform of FADS2, FADS20001, was detected in PBMCs and Jurkat cells. PBMC activation induced hypermethylation of a 470bp region in the FADS2 5'-regulatory sequence. This region was hypomethylated in Jurkat cells compared to quiescent PBMCs. These findings show that PUFA synthesis involving initial elongation and Δ8 desaturation is involved in regulating PBMC proliferation and is regulated via transcription possibly by altered DNA methylation. These processes were dysregulated in Jurkat cells. This has implications for understanding the regulation of mitosis in normal and transformed lymphocytes.

How does high DHA fish oil affect health? A systematic review of evidence

The health benefits of fish oil, and its omega-3 long chain polyunsaturated fatty acid content, have attracted much scientific attention in the last four decades. Fish oils that contain higher amounts of eicosapentaenoic acid (EPA; 20:5n-3) than docosahexaenoic acid (DHA; 22:6n-3), in a distinctive ratio of 18/12, are typically the most abundantly available and are commonly studied. Although the two fatty acids have traditionally been considered together, as though they were one entity, different physiological effects of EPA and DHA have recently been reported. New oils containing a higher quantity of DHA compared with EPA, such as fractionated and concentrated fish oil, tuna oil, calamari oil and microalgae oil, are increasingly becoming available on the market, and other oils, including those extracted from genetically modified oilseed crops, soon to come. This systematic review focuses on the effects of high DHA fish oils on various human health conditions, such as the heart and cardiovascular system, the brain and visual function, inflammation and immune function and growth/Body Mass Index. Although inconclusive results were reported in several instances, and inconsistent outcomes observed in others, current data provides substantiated evidence in support of DHA being a beneficial bioactive compound for heart, cardiovascular and brain function, with different, and at times complementary, effects compared with EPA. DHA has also been reported to be effective in slowing the rate of cognitive decline, while its possible effects on depression disorders are still unclear. Interestingly, gender- and age- specific divergent roles for DHA have also been reported. This review provides a comprehensive collection of evidence and a critical summary of the documented physiological effects of high DHA fish oils for human health.

Effects of a low and a high dietary LA/ALA ratio on long-chain PUFA concentrations in red blood cells

There is a debate about the optimal dietary ratio of LA and ALA to promote an efficient conversion of ALA to EPA and DHA, which have implications for human health.

Effects of a 12-week high-α-linolenic acid intervention on EPA and DHA concentrations in red blood cells and plasma oxylipin pattern in subjects with a low EPA and DHA status

The essential omega-3 fatty acid alpha-linolenic acid (ALA, 18:3n3) can be converted into EPA and DHA.

Effects of the flavonol quercetin and α-linolenic acid on n-3 PUFA status in metabolically healthy men and women: a randomised, double-blinded, placebo-controlled, crossover trial

Increased dietary intake and tissue status of the long-chain n-3 PUFA, EPA and DHA, is associated with cardiovascular benefits. Epidemiological and animal studies suggest that concomitant nutritive intake of flavonoids may increase the conversion of α-linolenic acid (ALA) to longer-chain n-3 fatty acids EPA and DHA. We investigated the effects of increased ALA intake on fatty acid composition of serum phospholipids and erythrocytes in metabolically healthy men and women and whether fatty acid profiles and ALA conversion were affected by regular quercetin intake or sex. Subjects (n 74) were randomised to receive at least 3·3 g/d ALA with either 190 mg/d quercetin (ALA+quercetin) or placebo (ALA+placebo) in a double-blinded, placebo-controlled, crossover trial with 8-week intervention periods separated by an 8-week washout period. A total of seven subjects dropped out for personal reasons. Data from the remaining sixty-seven subjects (thirty-four males and thirty-three females) were included in the analysis. Both interventions significantly increased serum phospholipid ALA (ALA+placebo: +69·3 %; ALA+quercetin: +55·8 %) and EPA (ALA+placebo: +37·3 %; ALA+quercetin: +25·5 %). ALA + quercetin slightly decreased DHA concentration by 9·3 %. Erythrocyte ALA and EPA significantly increased with both interventions, whereas DHA decreased. Fatty acid composition did not differ between sexes. We found no effect of quercetin. Intake of 3·6 g/d ALA over an 8-week period resulted in increased ALA and EPA, but not DHA, in serum phospholipids and erythrocytes. Neither quercetin supplementation nor sex affected the increment of ALA and relative proportions of n-3 PUFA in serum phospholipids and erythrocytes.

Omega-3-Fortified Lipid-Based Nutrient Supplement: Development, Characterization, and Consumer Acceptability

Background:

Incorporation of omega-3 polyunsaturated fatty acid (PUFA) sources to lipid-based nutrition supplement (LNS) formulations for undernourished populations presents a challenge due to reduced shelf life and poor consumer acceptability.

Objective:

To systematically develop an omega-3-fortified LNS formulation, using flaxseed oil (FO), by optimizing its processing stability and evaluating its sensory acceptance.

Methods:

LNS formulations were formulated to yield approximately 452 kcal, 13.2 g of protein, 30 g of fat, and 53 g of carbohydrates per 100 g. Response surface methodology (RSM) with 4-factor-3-level: omega-3 fatty acid source (FO; 0%-10%), antioxidant (ascorbyl palmitate: 0.0%-0.03%), emulsifier (soy lecithin: 0.5%-1.5%), and storage time (0-6 months at 40°C) was used to optimize LNS’s functionality and storage stability. Factor effects were evaluated for peroxide value, oil separation, water activity, moisture content, hardness, and vitamin C content of the samples. Consumer acceptability was assessed using a 9-point hedonic scale.

Results:

After 6 months of accelerated storage, the addition of FO to LNS formula resulted in increased peroxide values (7.75 mEq/kg fat) and lipid separation and a reduction in vitamin C and water activity. Optimal levels to maximize storage time and FO and minimize oxidation were 0.02% antioxidant, 1.5% emulsifier, and 4.9% FO. Indian women and students accepted LNS formulations with or without FO similar to other commercial supplements.

Conclusion:

An LNS containing FO with improved omega-6/omega-3 PUFA ratio was successfully formulated with staple Indian ingredients and optimized for storage stability using RSM.

Krill Oil-In-Water Emulsion Protects against Lipopolysaccharide-Induced Proinflammatory Activation of Macrophages In Vitro

Background: Parenteral nutrition is often a mandatory therapeutic strategy for cases of septicemia. Likewise, therapeutic application of anti-oxidants, anti-inflammatory therapy, and endotoxin lowering, by removal or inactivation, might be beneficial to ameliorate the systemic inflammatory response during the acute phases of critical illness. Concerning anti-inflammatory properties in this setting, omega-3 fatty acids of marine origin have been frequently described. This study investigated the anti-inflammatory and LPS-inactivating properties of krill oil (KO)-in-water emulsion in human macrophages in vitro. Materials and Methods: Differentiated THP-1 macrophages were activated using specific ultrapure-LPS that binds only on the toll-like receptor 4 (TLR4) in order to determine the inhibitory properties of the KO emulsion on the LPS-binding capacity, and the subsequent release of TNF-α. Results: KO emulsion inhibited the macrophage binding of LPS to the TLR4 by 50% (at 12.5 µg/mL) and 75% (at 25 µg/mL), whereas, at 50 µg/mL, completely abolished the LPS binding. Moreover, KO (12.5 µg/mL, 25 µg/mL, or 50 µg/mL) also inhibited (30%, 40%, or 75%, respectively) the TNF-α release after activation with 0.01 µg/mL LPS in comparison with LPS treatment alone. Conclusion: KO emulsion influences the LPS-induced pro-inflammatory activation of macrophages, possibly due to inactivation of the LPS binding capacity.

The effects of elevated subcutaneous fat stores on fatty acid composition and gene expression of proinflammatory markers in periparturient dairy cows

During the periparturient period, elevated circulating nonesterified fatty acids (NEFA) from excessive lipid mobilization affect not only the circulating fatty acid (FA) composition, but also that of the peripheral blood mononuclear cells (PBMC) and polymorphonuclear leukocytes (PMNL). However, the changes to specific lipid fractions remain unknown. We hypothesized that elevated lipid mobilization will alter FA profiles and gene expression of selected proinflammatory mediators in PBMC and PMNL. Starting -28 d relative to expected calving (d 0), treatment cows (n = 18) received a dry cow ration plus an additional 10 kg of corn/head per day, while the control cows (n = 16) received the dry cow ration (no additional corn) supplemented with 400 mg of monensin/head per day to minimize lipid mobilization. Postpartum, treatment cows were feed deprived for 8 h on d +3. For FA analysis, serum was collected on d -28 and -7 relative to expected parturition and d +1, +3, +6, +15, and +21 postpartum, in addition to milk samples. Immune cells, PBMC and PMNL, were isolated on d -28, +3, +12, and +21 for FA analysis and gene expression analysis by reverse-transcription PCR. Serum, PBMC, and PMNL lipids were fractionated into NEFA and phospholipids (PL). The FA composition of milk, serum, PBMC, and PMNL was analyzed by gas chromatography. Data were analyzed as repeated measures ANOVA using mixed model procedures in SAS (9.3) with significance declared at P ≤ 0.05. Several FA varied by treatment and across time and parity. Within the serum PL fraction, FA associated with altered immune function, C18:3n-6, C20:4, C20:5, total n-3, and the ratio of n-6 to n-3 varied significantly by a treatment × parity × time interaction. Overall, FA composition of NEFA and PL fractions from PBMC and PMNL did not significantly reflect FA of serum. Gene expression for IL-1β in PBMC was greater for control, whereas ICAM, IL-1β, IL-6, and TNF-α were greater in primiparous than multiparous cows, without a detectable treatment effect. Whereas gene expression of CASP, IL-8R, and SELL in PMNL changed over time, no treatment effect was detected. In summary, high-energy prepartal diets altered FA profile in serum, milk, PBMC, and PMNL lipids; however, gene expression of selected proinflammatory mediators was not significantly affected.

Differential effects of palmitoleic acid on human lymphocyte proliferation and function

BACKGROUND

Palmitoleic acid (PA) is a n-7 monounsaturated fatty acid (MUFA) secreted by adipose tissue and related to decreased insulin resistance in peripheral tissues. Evidences have been shown that PA also decreased proinflammatory cytokine expression in cultured macrophages. Although studies have shown that other fatty acids (FAs) modulate several lymphocyte functions, the specific effect of PA on these cells is unknown. The aim of the present study was to evaluate the possible influence of PA on activation and differentiation of human lymphocytes in comparison to oleic acid (OA).

METHODS

Human lymphocytes were isolated from peripheral blood of health men and cultured in the presence of growing concentrations of PA or OA (5 to 200 μM), for 24 h. After that, cells were collected and cytotoxicity evaluated by flow cytometry. Then, we analyzed proliferative capacity in lymphocytes treated with non toxic concentrations of PA and OA (25 and 50 μM, respectively), in the presence or absence of concanavalin A (ConA). The Th1/Th2/Th17 cytokine production was determined by the Cytometric Bead Array. CD28 and CD95 surface expression and T regulatory cell percentage were determined by flow cytometry.

RESULTS

We observed that PA is toxic to lymphocytes above 50 μM. PA promoted a decrease of lymphocyte proliferation stimulated by ConA in both concentrations. PA also decreased CD28 externalization and increased CD95. On the other hand, OA did not alter these parameters. In the same way, PA reduced IL6, IFN-gamma, TNF-alpha and IL17A production in both concentration and IL2 only at 50 μM (in the presence of ConA). OA promoted IFN-gamma reduction in both concentrations and an increase of IL-2, IL4 and IL10 at 25 μM. Both fatty acids decreased the percentage of T regulatory cells.

CONCLUSION

In conclusion, PA promoted a suppressive effect on lymphocyte proliferation characterized by a decrease of Th1 and Th17 response, and co-stimulatory molecule (CD28). However, OA increased lymphocyte proliferation through IL2 production and Th2 response. These results also show a more suppressive effect of PA on lymphocytes in comparison to OA.

Diet and Inflammation in Alzheimer's Disease and Related Chronic Diseases: A Review

Inflammation is one of the pathological features of the neurodegenerative disease, Alzheimer's disease (AD). A number of additional disorders are likewise associated with a state of chronic inflammation, including obesity, cardiovascular disease, and type-2 diabetes, which are themselves risk factors for AD. Dietary components have been shown to modify the inflammatory process at several steps of the inflammatory pathway. This review aims to evaluate the published literature on the effect of consumption of pro- or anti-inflammatory dietary constituents on the severity of both AD pathology and related chronic diseases, concentrating on the dietary constituents of flavonoids, spices, and fats. Diet-based anti-inflammatory components could lead to the development of potent novel anti-inflammatory compounds for a range of diseases. However, further work is required to fully characterize the therapeutic potential of such compounds, including gaining an understanding of dose-dependent relationships and limiting factors to effectiveness. Nutritional interventions utilizing anti-inflammatory foods may prove to be a valuable asset in not only delaying or preventing the development of age-related neurodegenerative diseases such as AD, but also treating pre-existing conditions including type-2 diabetes, cardiovascular disease, and obesity.

Omega-3 fatty acids, inflammatory status and biochemical markers of patients with systemic lupus erythematosus: a pilot study

BACKGROUND

Studies have shown that omega-3 fatty acids reduce the concentrations of eicosanoids, cytokines, chemokines, C-reactive protein (CRP) and other inflammatory mediators.

OBJECTIVE

To investigate the effects of omega-3 fatty acids on circulating levels of inflammatory mediators and biochemical markers in women with systemic lupus erythematosus (SLE).

METHODS

Experimental clinical study (clinical trial: NCT02524795); 49 women with SLE (ACR1982/1997) were randomized: 22 to the omega-3 group (daily intake of 1080mg EPA+200mg DHA, for 12 weeks) and 27 to the control group. The inflammatory mediators and biochemical markers at T0 and T1 in omega-3 group were compared using Wilcoxon test. U-Mann-Whitney test was used to compare variations of measured variables [ΔV=pre-treatment (T0)-post-treatment (T1) concentrations] between groups. p<0.05 was considered significant.

RESULTS

The median (interquartile range - IQR) of age was 37 (29-48) years old, of disease duration was 7 (4-13) years, and of SLEDAI-2K was 1 (0-2). The median (IQR) of variation in CRP levels between the two groups showed a decrease in omega-3 group while there was an increase in control group (p=0.008). The serum concentrations of IL-6 and IL-10, leptin and adiponectin did not change after a 12 week treatment.

CONCLUSIONS

Supplementation with omega-3 had no impact on serum concentrations of IL-6, IL-10, leptin and adiponectin in women with SLE and low disease activity. There was a significant decrease of CRP levels as well as evidence that omega-3 may impact total and LDL-cholesterol.

Ameliorative effect of flaxseed oil against thiacloprid-induced toxicity in rats: hematological, biochemical, and histopathological study

The present study was carried out to evaluate the hematological, biochemical, and histopathological changes due to thiacloprid toxicity, and the potential protective role of flaxseed oil in male Wistar albino rats. Subacute thiacloprid intoxication induced a significant increase in RBCs, Hb, PCV, and WBCs count, and bone marrow micronucleus (MN) formation. Moreover, there was a significant increase in serum biochemical parameters related to hepatic injury: alanine aminotransferase (ALT) and alkaline phosphatase (ALP). Serum total protein and albumin levels were significantly reduced. Thiacloprid increases tumor necrosis factor-alpha (TNF-α) and interleukine-2(IL-2). There was a significant decrease in glutathione-S-transferase, while the lipid peroxidation (MDA) and cytochrome P450 activity were significantly increased. Flaxseed oil coadministration partially retrieved the changes in all studied parameters. Thiacloprid induced histopathological liver damage, which was minimized as a result of flaxseed oil treatment. In general, it was concluded that, flaxseed oil able to protect against thiacloprid-induced hepatoxicity.

Preliminary evaluation of a differential effect of an α-linolenate-rich supplement on ketogenesis and plasma ω-3 fatty acids in young and older adults

OBJECTIVES

The aim of the present study was to compare the effects of an α-linolenic acid-rich supplement (ALA-RS) on the ketogenic response and plasma long-chain ω-3 polyunsaturated fatty acid in healthy young adults and older individuals.

METHODS

Ten young (25 ± 0.9 y) and 10 older adults (73.1 ± 2.2 y) consumed a flaxseed oil supplement providing 2 g/d of ALA for 4 wk. Plasma ketones, nonesterified fatty acids (NEFA), triacylglycerols, glucose, and insulin were measured over 6 h, before and after supplementation. Total body fat mass was assessed before and after the ALA-RS.

RESULTS

The ALA-RS did not significantly modify fasting ketones but postprandial production of β-hydroxybutyrate was increased by 26% (P = 0.037) only in the young adult group. Fasting plasma ketones were positively correlated to fasting plasma NEFA (P < 0.01) in both groups. However, the relation was shifted to the right in the older group, suggesting that older adults needed higher plasma NEFA levels to achieve the same ketone amounts as young adults. At baseline, the older group had 47% higher total plasma fatty acids than the young group (P = 0.007). After the ALA-RS, plasma ALA doubled in both groups (P < 0.01), an effect that was associated in the older group with a 40% higher eicosapentaenoic acid (EPA; P = 0.004), but no difference in docosahexaenoic acid. The postsupplementation increase in plasma ALA correlated positively with percent total body fat, especially in the older group (r(2) = 0.77; P = 0.0016).

CONCLUSION

In young adults, ALA-RS mildly stimulated postprandial ketogenesis, whereas in the older group, it favored increased plasma ALA and EPA.

The effect of modifying dietary LA and ALA intakes on omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) status in human adults: a systematic review and commentary

This paper presents a systematic review of human studies investigating the effect of altering dietary omega-3 polyunsaturated fatty acid (n-3 PUFA) alpha-linolenic acid (ALA) and omega-6 polyunsaturated fatty acid (n-6 PUFA) linoleic acid (LA) intakes on n-3 long-chain polyunsaturated fatty acid (LCPUFA) status in adult humans. The results suggest that it is possible to increase n-3 LCPUFA status by reducing LA and/or increasing ALA intake in humans, although decreasing LA intake to below 2.5%E may be required to specifically increase levels of the n-3 LCPUFA docosahexaenoic acid (DHA). The majority of studies in this area to date have been relatively poor in quality, which limits the ability to draw robust conclusions, and we present a series of recommendations to improve the quality of future studies in fatty acid nutrition in humans.

EPA and DHA exposure alters the inflammatory response but not the surface expression of Toll-like receptor 4 in macrophages

Dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and their respective enrichment in cell membranes have been negatively associated with atherosclerotic lesion development. This effect may be mediated, in part, by dampened inflammatory response of macrophages triggered by toll-like receptor 4 (TLR4) activation. This study investigated the influence of membrane fatty acid profile on TLR4-mediated inflammation in RAW 264.7 macrophages. Cells pretreated with myristic acid (MA), EPA, DHA or vehicle control for 24 h were stimulated with ultra-pure LPS, a specific TLR4 agonist, for 6 or 24 h, corresponding to early and late stages of TNFα and IL-6 protein induction. Treatment significantly increased cell membrane MA, EPA, and DHA by 4.5-, 20.6-, and 8.9-fold, respectively. MA significantly increased IL-6 secretion 6 h post-exposure to the fatty acid, but did not change TNFα secretion in response to any other treatment condition. EPA and DHA significantly reduced TNFα secretion by 36 and 41 %, respectively, in cells stimulated for 24 h but not 6 h. In contrast, EPA and DHA significantly reduced IL-6 secretion at both 6 h (67 and 72%, respectively) and 24 h (69 and 72%, respectively). MA or DHA treatment had no significant effect compared to vehicle on factors influencing cellular LPS recognition, including LPS-cell association, and cell surface expression of TLR4, TLR4-MD2 complex, and CD14. These data suggest that membrane fatty acid profiles influence the TLR4-mediated inflammatory response in macrophages, via mechanisms that occur downstream of TLR4 receptor activation.

[Polyunsaturated omega-3 fatty acids and systemic lupus erythematosus: what do we know?]

Various studies have demonstrated the impact of omega-3 fatty acids on the concentration of C reactive protein (CRP), pro-inflammatory eicosanoids, cytokines, chemokines and other inflammatory mediators. Therefore, the supplementation of these types of lipids may represent additional option treatment for chronic systemic diseases, such as Systemic Lupus Erythematous and other rheumatic diseases. The role of these lipids has not been well established, yet. However, it seems there is a direct relationship between its intake and the decrease of the disease clinical manifestations as well as of the inflammatory status of the patients. Thus, the aim of this manuscript is to present a thorough review on the effects of omega-3 fatty acids in patients with SLE. Bibliographic data set as the Medical Literature Analysis and Retrieval System Online (MEDLINE) and Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) were searched using as key words: systemic lupus erythematous (SLE), polyunsaturated fatty acids omega-3, eicosapentanoic acid (EPA), docosahexanoic acid (DHA), antioxidants and diet. Manuscripts published up to September 2013 were included. There were 43 articles related to the topic, however only 15 pertained human studies, with three review articles and 12 clinical studies.

Omega-6 to omega-3 fatty acid ratio and higher-order cognitive functions in 7- to 9-y-olds: a cross-sectional study

BACKGROUND

Biochemical and behavioral evidence has suggested that the ratio of n-6 (omega-6) to n-3 (omega-3) could be an important predictor of executive function abilities in children.

OBJECTIVE

We determined the relation between the ratio of n-6 to n-3 and cognitive function in children. We hypothesized that children with lower ratios of n-6 to n-3 fatty acids would perform better on tests of planning and working memory.

DESIGN

Seventy 7- to 9-y-old children completed three 24-h diet recalls and a subset of the Cambridge Neuropsychological Test Assessment Battery. Parents provided information on their demographics and children's diet histories.

RESULTS

Mean n-3 and mean n-6 intakes were related to the mean time spent on each action taken in the planning problem. The ratio of n-6 to n-3 significantly predicted performance on the working memory and planning problems. There was a significant interaction between the ratio and fatty acid intake; when children had high ratios, a higher intake of n-3 fatty acids predicted a better performance on the planning task than when children had lower n-3 intakes. When children had low ratios, a lower intake of n-3 and lower intake of n-6 predicted better performance than when intakes were higher.

CONCLUSIONS

The relation between cognitive abilities and the ratio of n-6 to n-3 may be mediated by an enzymatic affinity for n-3 fatty acids. The ratio of n-6 to n-3 should be considered an important factor in the study of fatty acids and cognitive development. This trial was registered at clinicaltrials.gov as NCT01823419.

The impact of long-chain n-3 polyunsaturated fatty acids on human health

A considerable literature has been published on the health benefits of fish, oil-rich fish and fish oils and their constituent long-chain (LC) n-3 PUFA. Evidence from epidemiological studies highlights the cardioprotective attributes of diets rich in fish, especially oil-rich fish. Data from intervention trials are consistent in suggesting that LC n-3 PUFA lower the risk of CVD, probably by the multiple mechanisms of lowering serum triacylglycerols, improving the LDL:HDL ratio, anti-arrhythmic effects on heart muscle, improved plaque stability, anti-thrombotic effects and reduced endothelial activation. Research indicates LC n-3 PUFA provision has an impact during development, and there is preliminary evidence that docosahexaenoic acid supplementation during pregnancy could optimise brain and retina development in the infant. LC n-3 PUFA are also postulated to ameliorate behavioural and mental health disturbances such as depression, schizophrenia, dementia and attention deficit hyperactivity disorder. However, despite some positive evidence in each of these areas, use of LC n-3 PUFA in these conditions remains at the experimental stage. In the case of immune function, there is little doubt that LC n-3 PUFA have a positive effect. Although intervention trials in rheumatoid arthritis show strong evidence of benefit, evidence for efficacy in other inflammatory conditions, including Crohn's disease, ulcerative colitis, psoriasis, lupus, multiple sclerosis, cystic fibrosis and asthma, is inconsistent or inadequate. More promising evidence in some conditions may come from studies which attempt to modify the fetal environment using LC n-3 PUFA supplementation during pregnancy.

Influence of marine n-3 polyunsaturated fatty acids on immune function and a systematic review of their effects on clinical outcomes in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease of the joints and bones. The n-6 polyunsaturated fatty acid (PUFA) arachidonic acid (ARA) is the precursor of inflammatory eicosanoids which are involved in RA. Some therapies used in RA target ARA metabolism. Marine n-3 PUFAs (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) found in oily fish and fish oils decrease the ARA content of cells involved in immune responses and decrease the production of inflammatory eicosanoids from ARA. EPA gives rise to eicosanoid mediators that are less inflammatory than those produced from ARA and both EPA and DHA give rise to resolvins that are anti-inflammatory and inflammation resolving, although little is known about these latter mediators in RA. Marine n-3 PUFAs can affect other aspects of immunity and inflammation relevant to RA, including dendritic cell and T cell function and production of inflammatory cytokines and reactive oxygen species, although findings for these outcomes are not consistent. Fish oil has been shown to slow the development of arthritis in animal models and to reduce disease severity. A number of randomised controlled trials of marine n-3 PUFAs have been performed in patients with RA. A systematic review included 23 studies. Evidence is seen for a fairly consistent, but modest, benefit of marine n-3 PUFAs on joint swelling and pain, duration of morning stiffness, global assessments of pain and disease activity, and use of non-steroidal anti-inflammatory drugs.

Relationship between immunological parameters and the severity of neutropenia and effect of enteral nutrition on immune status during neoadjuvant chemotherapy on patients with advanced esophageal cancer

OBJECTIVES

Chemotherapy may cause various toxicities as well as impair immunological function. However, little is known about the relationship between toxicities and immunological parameters or the effect of enteral nutrition (EN) on immunological status during chemotherapy.

METHODS

91 patients who received neoadjuvant chemotherapy (NACT) for esophageal cancer were randomly assigned to receive either EN or parenteral nutrition (PN). Immunological parameters, including total lymphocyte count (TLC), type 1 and type 2 CD4-positive T cells (Th1/Th2) balance, human leukocyte antigen (HLA)-DR expression on monocytes, natural killer cell activity, and phytohemagglutinin-stimulated lymphocyte proliferation were measured at baseline and day 14 of the first chemotherapy cycle.

RESULTS

In the PN group, patients with grade 3-4 neutropenia showed significantly lower TLC, HLA-DR expression, and Th1/Th2 balance at day 14 compared to those with grade 0-2 neutropenia. Among pretherapeutic factors, Th1/Th2 balance was the only factor significantly associated with the severity of neutropenia. Concerning the comparison of immunological parameters between the EN and PN groups, HLA-DR expression at day 14 was significantly higher in the EN group.

CONCLUSIONS

Baseline Th1/Th2 balance predicted the severity of neutropenia, and EN significantly reduced the decline of monocyte HLA-DR expression in patients with esophageal cancer receiving NACT.