Effect of Dietary Fatty Acid Composition on Th1/Th2 Polarization in Lymphocytes

Background: It has become increasingly clear that polyunsaturated fatty acids (PUFAs) have immunomodulatory effects. However, the intake of these fatty acids used in animal studies often greatly exceeds dietary human intake. Whether differences in the composition of fatty acids that are consumed in amounts consistent with normal dietary intake can influence immune function remains uncertain. Methods: We manufactured 3 types of liquid diet, related to modified fatty acid composition (ω‐6/ω‐3 = 0.25, 2.27 and 42.9), but excluding eicosapentaenoic acid and docosahexaenoic acid, based upon a liquid diet used clinically in humans. We assessed CD3‐stimulated cytokine production of splenocytes in female BALB/c mice (n = 4 per group) fed 1 of 3 liquid diets for 4 weeks. We also measured the cytokine production of peripheral blood mononuclear cells stimulated with phorbol myristate acetate and ionomycin in humans at the end of a 4‐week period of consumption of 2 different liquid diets (ω‐6/ω‐3 = 3 and 44). Results: We found that the ratio of interfero ω‐γ (IFN‐γ) / interleukin‐4 (IL‐4) was significantly higher in mice fed theω ‐3 rich diet than in others. In humans, IFN‐γ / IL‐4 was significantly higher after the ω‐3 versus the ω‐6 enhanced diet. Conclusions: Differences in the composition of ω‐3 andω ‐6 PUFAs induces a shift in the Th1/Th2 balance in both mouse and human lymphocytes, even when ingested in normal dietary amounts. An ω‐3 rich diet containing α‐linolenic acid modulates immune function.     

Dietary ω‐6/ω‐3 Polyunsaturated Fatty Acid Ratios Affect the Homeostasis of Th/Treg Cells in Mice With Dextran Sulfate Sodium–Induced Colitis

Background: This study evaluated the effect of different dietary ω‐6/ω‐3 polyunsaturated fatty acid (PUFA) ratios on modulating helper T (Th) and regulatory T (Treg) lymphocytes in mice with dextran sulfate sodium (DSS)–induced colitis. Methods: There were 3 control and 3 colitis groups. Mice were fed for 24 days with diets with soybean oil (S), a mixture of soybean oil and low fish oil content (LF), or high fish oil content (HF). The ratio of ω‐6/ω‐3 PUFA in the LF diet was 4:1, and that in the HF diet was 2:1. The control groups drank distilled water while colitis groups were provided 2% DSS in drinking water during days 15–19. All mice drank distilled water from days 20–24 for recovery and were sacrificed on day 25. Results: Colitis resulted in higher blood Th1, Th2, and Th17 and lower Treg percentages. Also, plasma haptoglobin and proinflammatory chemokines were elevated in colon lavage fluid. Colitic groups with fish oil had lower inflammatory mediators in the plasma and colon lavage fluid. Furthermore, the percentages of blood Th1, Th2, and Th17 cells were lower, whereas Treg cell percentages were higher than those in the soybean oil group. The colitis group with an ω‐6/ω‐3 PUFA ratio of 2:1 had more pronounced effects than the group with a ratio of 4:1. Conclusions: Diets with an ω‐6/ω‐3 PUFA ratio of 2:1 or 4:1 regulate the Th/Treg balance and attenuate inflammatory mediator production in colitis. Compared with the ω‐6/ω‐3 PUFA ratio of 4:1, the ratio of 2:1 was more effective in reducing inflammatory reactions in DSS‐induced colitis.     

Rapid Enrichment of Cell Phospholipids in Long‐Chain Polyunsaturated ω‐3 Fatty Acids After a Bolus Intravenous Injection of a Medium‐Chain Triacylglycerol

The present review aims at highlighting the use of a recently developed medium‐chain triacylglycerol:fish oil (MCT:FO) emulsion for the rapid and sustained enrichment of long‐chain polyunsaturated ω‐3 fatty acids in cell phospholipids. Preclinical in vitro, in vivo, and ex vivo experiments are briefly considered with emphasis on the changes in the fatty acid pattern of cell phospholipids in several organs, the partial correction of liver steatosis, and the cardiovascular modification of cationic and functional variables observed in ω‐3‐depleted rats examined 60–120 minutes after a bolus intravenous (IV) injection (1.0 mL) of the MCT:FO emulsion. The clinical findings collected in healthy male volunteers before or after the bolus IV injection (50.0 mL) of either the MCT:FO emulsion or a control medium‐chain triacylglycerol:long‐chain triacylglycerol emulsion are also reviewed, with emphasis on the rapid (within 60 minutes) and sustained (up to 2–3 days) enrichment of platelet and white blood cell phospholipids in long‐chain polyunsaturated ω‐3 fatty acids and hemostatic safety of the present procedure proposed as a tool for the rapid prevention or correction of metabolic and functional disturbances in humans with a relative deficiency in such ω‐3 fatty acids.     

Effects of ω‐3 Polyunsaturated Fatty Acids on the Homeostasis of CD4+ T Cells and Lung Injury in Mice With Polymicrobial Sepsis

Background: Sepsis is a common cause of death in critically ill patients. An overwhelming inflammatory response and imbalance of helper T (Th) cells and regulatory T (Treg) cells are thought to be involved in the progression of sepsis. ω‐3 Polyunsaturated fatty acids (PUFAs) were found to have anti‐inflammatory and immunomodulatory properties. This study investigated the effects of ω‐3 PUFAs on the balance of Th subsets, Treg cells, and the inflammatory response in septic mice. Methods: Mice were randomly assigned to soybean oil (SO) and fish oil (FO) groups. The 2 groups received an identical nutrient distribution except for the sources of the fat. The SO group was fed soybean oil, while part of the soybean oil was replaced by fish oil in the FO group. The FO group had an ω‐6/ω‐3 PUFA ratio of 2:1. After feeding the diets for 3 weeks, sepsis was induced by cecal ligation and puncture (CLP), and mice were sacrificed on days 0, 1, and 3. Results: Compared with the SO group, the FO group had lower inflammatory mediator levels in the plasma and peritoneal lavage fluid after CLP. Also, the FO group had lower Th1, Th2, and Th17 percentages and a higher Th1/Th2 ratio in blood. In lung tissues, neutrophil infiltration was reduced, whereas peroxisome proliferator–activated receptor γ expression was upregulated. Conclusions: A fish oil diet with an ω‐6/ω‐3 PUFA ratio of 2:1 may elicit more balanced Th polarization, alleviate inflammatory responses, and attenuate lung injury in CLP‐induced sepsis.     

ω‐3 Fatty Acids Prevent Hepatic Steatosis,Independent of PPAR‐α Activity,in a Murine Model of Parenteral Nutrition–Associated Liver Disease

Objectives: ω‐3 Fatty acids (FAs), natural ligands for the peroxisome proliferator‐activated receptor–α (PPAR‐α), attenuate parenteral nutrition–associated liver disease (PNALD). However, the mechanisms underlying the protective role of ω‐3 FAs are still unknown. The aim of this study was to determine the effects of ω‐3 FAs on hepatic triglyceride (TG) accumulation in a murine model of PNALD and to investigate the role of PPAR‐α and microsomal triglyceride transfer protein (MTP) in this experimental setting. Methods: 129S1/SvImJ wild‐type or 129S4/SvJaePparatm/Gonz/J PPAR‐α knockout mice were fed chow and water (controls); oral, fat‐free PN solution only (PN‐O); PN‐O plus intraperitoneal (IP) ω‐6 FA‐predominant supplements (PN–ω‐6); or PN‐O plus IP ω‐3 FA (PN–ω‐3). Control and PN‐O groups received sham IP injections of 0.9% NaCl. Hepatic histology, TG and cholesterol, MTP activity, and PPAR‐α messenger RNA were assessed after 19 days. Results: In all experimental groups, PN feeding increased hepatic TG and MTP activity compared with controls. Both PN‐O and PN–ω‐6 groups accumulated significantly greater amounts of TG when compared with PN–ω‐3 mice. Studies in PPAR‐α null animals showed that PN feeding increases hepatic TG as in wild‐type mice. PPAR‐α null mice in the PN‐O and PN–ω‐6 groups demonstrated variable degrees of hepatic steatosis, whereas no evidence of hepatic fat accumulation was found after 19 days of oral PN plus IP ω‐3 FAs. Conclusions: PN induces TG accumulation (steatosis) in wild‐type and PPAR‐α null mice. In PN‐fed wild‐type and PPAR‐α null mice given IP ω‐3 FAs, reduced hepatic TG accumulation and absent steatosis are found. Prevention of steatosis by ω‐3 FAs results from PPAR‐α–independent pathways.     

The Role of the ω‐3 Fatty Acid DHA in the Human Life Cycle

Dietary consumption of the essential fatty acids linoleic acid (LA; ω‐6) and α‐linolenic acid (ALA; ω‐3) is necessary for human growth and development. In the past 150 years, the average Western diet has changed dramatically such that humans today consume a much higher proportion of ω‐6 fatty acids relative to ω‐3 fatty acids than ever before. The importance of ω‐3 fatty acids in human development has been well established in fetal and neonatal development, with brain and retinal tissues highly dependent on ω‐3 fatty acids, specifically docosahexaenoic acid (DHA) for membrane fluidity and signal transduction. In childhood, ω‐3s have been shown to contribute to ongoing cognitive development and may be involved in metabolic programming of bone turnover and adipogenesis. ω‐3s may also play important roles in adult neurophysiology and disease prevention.     

Effects of ω‐3 Fish Oil Lipid Emulsion Combined With Parenteral Nutrition on Patients Undergoing Liver Transplantation

Background: The effect of parenteral nutrition (PN) support supplemented with ω‐3 fatty acids was investigated in a randomized, controlled clinical trial at the Affiliated Drum Tower Hospital, Medical School of Nanjing University. Materials and Methods: Ninety‐eight patients with the diagnosis of end‐stage liver disease or hepatic cellular carcinoma were admitted for orthotopic liver transplantation at the Affiliated Drum Tower Hospital. The patients were randomly divided into 3 groups: diet group (n = 32), PN group (n = 33), and polyunsaturated fatty acid (PUFA) group (n = 33). Patients in the PN and PUFA groups received isocaloric and isonitrogenous PN for 7 days after surgery. Venous heparin blood samples were obtained for assay on days 2 and 9 after surgery. A pathological test was performed after reperfusion of the donor liver and on day 9. Results: Alanine aminotransferase levels were improved significantly by PUFA treatment compared with traditional PN support (P < .05). Compared with the results on day 9 in the PN group, a significant difference was seen in the extent of increase of the prognostic nutrition index and prealbumin in the PUFA group. The pathological results also showed that ω‐3 fatty acid supplementation reduced hepatic cell injury. PUFA therapy also decreased the incidence of infectious morbidities and shortened the posttransplant hospital stay significantly. Conclusion: Posttransplant PN support can greatly improve metabolism of protein and nutrition states of patients. ω‐3 fatty acid–supplemented PN significantly reduces injury of the transplanted liver, decreases the incidence of infectious morbidities, and shortens posttransplant hospital stay.     

Soybean and Fish Oil Mixture With Different ω‐6/ω‐3 Polyunsaturated Fatty Acid Ratios Modulates Dextran Sulfate Sodium–Induced Changes in Small Intestinal Intraepithelial γδT‐Lymphocyte Expression in Mice

Background: This study investigated the effect of different ω‐6/ω‐3 polyunsaturated fatty acid (PUFA) ratios on dextran sulfate sodium (DSS)–induced changes to small intestinal intraepithelial lymphocyte (IEL) γδT‐cell expression. Methods: Mice were assigned to 3 control and 3 DSS‐treated groups and were maintained on a low‐fat semipurified diet. One of the control (S) groups and a DSS (DS) group were provided with soybean oil; the other 2 control (Hω‐3 and Lω‐3) groups and 2 other DSS (DHω‐3 and DLω‐3) groups were fed either a soybean and fish oil mixture with a ω‐6/ω‐3 ratio of 2:1 or 4:1. After feeding the respective diets for 2 weeks, the DSS groups were given distilled water containing 2% DSS, and the control groups were given distilled water for 5 days. All groups were further provided distilled water 5 days for recovery, and the small intestinal IEL γδT‐cell subset was isolated for analysis. Results: DSS treatment resulted in a lower small intestinal IEL γδT‐cell percentage and higher messenger RNA (mRNA) expressions of Reg IIIγ, keratinocyte growth factor (KGF), and complement 5a receptor (C5aR) by IEL γδT cells. Fish oil administration enhanced the proportion of small intestinal IEL γδT cells. Compared with the DLω‐3 group, the DHω‐3 group had lower Reg IIIγ, KGF, and C5aR mRNA expressions and higher expression of peroxisome proliferator‐activated receptor (PPAR)–γ gene by small intestinal IEL γδT cells. Conclusions: Fish oil diets with a ω‐6/ω‐3 PUFA ratio of 2:1 were more effective than those with a ratio of 4:1 in improving DSS‐induced small intestinal injury, and activation of PPAR‐γ in IEL γδT cells may be associated with resolution of small intestinal inflammation.     

Intravenous ω‐3 Fatty Acids Plus Gemcitabine

Background: Marine‐derived ω‐3 fatty acids (ω‐3FAs) have proven antitumor activity in vivo and in vitro and improve quality of life (QOL) in clinical cancer studies. These changes may be mediated by reduction in circulating proangiogenic and proinflammatory factors. In this first study of intravenous ω‐3FAs as a therapy in cancer patients, we aimed to assess if it could augment the antitumor activity of gemcitabine in patients with advanced pancreatic cancer and improve QOL. Materials and Methods: Patients were administered gemcitabine 1000 mg/m³ weekly followed by up to 100 g (200 mg/mL) of ω‐3 rich lipid emulsion for 3 weeks followed by a rest week. This was continued for up to 6 cycles, progression, unacceptable toxicity, patient request, or death. The primary outcome measure was objective response rate, with secondary outcome measures of overall and progression free survival, QOL scores, and adverse events. Results: Fifty patients were recruited. Response rate was 14.3% and disease control rate was 85.7%. Overall and progression free survival were 5.9 and 4.8 months, respectively. Increase in global health of > 10% over baseline was seen in 47.2% of patients. More than 50% of patients had > 10% increase in QOL scores in generic symptom scores and both disease‐specific domains. Grade 3/4 adverse events were thrombocytopenia (8%), neutropenia (12%), nausea or vomiting (4%), and chills (6%). Conclusion: Intravenous ω‐3FAs in combination with gemcitabine shows evidence of improved activity and benefit to QOL in patients with advanced pancreas cancer and is worthy of investigation in a randomized phase III trial.     

Rapid Incorporation of ω‐3 Fatty Acids Into Colonic Tissue After Oral Supplementation in Patients With Colorectal Cancer

Background: The purpose of the study was to examine whether a preoperative supplement with ω‐3 fatty acids (FAs) leads to their incorporation into colonic tissue in patients scheduled for colorectal cancer surgery. This would be of interest because ω‐3 FAs have potential beneficial (local) immunological effects that might benefit these patients. Methods: In a randomized, double‐blind, prospective, placebo‐controlled, single‐center intervention trial, patients referred for elective colorectal cancer surgery received either an ω‐3 FA–enriched oral nutrition supplement (ONS) (200 mL twice daily) providing 2.0 g of eicosapentaenoic acid (EPA) and 1.0 g of docosahexaenoic acid (DHA) per day or a standard ONS for 7 days before surgery. Tissue samples from healthy colonic tissue (mucosa and muscular layer) were obtained during surgery, and tissue fatty acid composition was analyzed by gas chromatography. Results: EPA was significantly higher in colonic mucosa (P = .001) and in the colonic muscular layer (P = .004) in the ω‐3 FA group compared with controls. Patients in the ω‐3 FA group also tended to have higher docosapentaenoic acid and DHA levels in colonic tissue. Conclusions: EPA is incorporated rapidly into colonic mucosa and colonic muscular layer in patients given 3 g of ω‐3 FA daily for 7 days before surgery for colorectal cancer. This may lead to potential beneficially effects on (local) immune function, which might benefit these patients.     

Effects of the ω‐6:ω‐3 Fatty Acid Ratio of Fat Emulsions on the Fatty Acid Composition in Cell Membranes and the Anti‐Inflammatory Action

Background: This study investigated the effects of parenterally administered fish oil (FO) on the fatty acid composition in rats to determine the optimal ω‐6:ω‐3 polyunsaturated fatty acid (PUFA) ratio of fat emulsions to achieve an anti‐inflammatory effect. Methods: Male Sprague‐Dawley rats were infused a parenteral nutrition (PN) solution containing fat emulsions with different ω‐6:ω‐3 PUFA ratios. The fatty acid content of phospholipids in the membranes of splenocytes was analyzed by gas chromatography (experiment 1). In addition, the amounts of leukotriene (LT) B₄ and LTB₅ released from peritoneal polymorphonuclear leukocytes (PMNs) were measured by high‐performance liquid chromatography (experiment 2). Results: In experiment 1, after infusion of the fat emulsion containing FO, the ω‐3 PUFA content in cell membranes rose to 70% of the peak value on day 1 and nearly reached a plateau on day 3. The highest ratio of eicosapentaenoic acid (EPA) to arachidonic acid (AA) was achieved by administrating a PN solution with the smallest ω‐6:ω‐3 PUFA ratio. In experiment 2, a larger amount of LTB₅ was released from Ca‐ionophore‐stimulated PMNs taken from rats given a larger quantity of FO. The ratio of LTB₅:LTB₄ released from PMNs correlated positively with the EPA:AA ratio in the membranous phospholipid and in serum. Conclusions: The ω‐3 PUFAs were readily incorporated into the cell membrane within 3 days of infusion with the fat emulsion. The EPA:AA ratio in membranous phospholipid in PMNs was positively correlated with the LTB₅:LTB₄ production ratio and was a good indicator of anti‐inflammatory effects.     

Restoration of Mannose‐Binding Lectin Complement Activity Is Associated With Improved Outcome in Patients With Advanced Pancreatic Cancer Treated With Gemcitabine and Intravenous ω‐3 Fish Oil

Background: Pancreatic cancer has an extremely poor clinical outcome. Surrogate biomarkers for outcome are scarce. There is mixed evidence for the association of high mannose‐binding lectin (MBL) complement activity with cancer outcomes, including reduced survival and increased infectious complications. ω‐3–rich fatty acids (ω‐3FA) attenuate production of proinflammatory cytokines and potentially manipulate complement activity. Materials and Methods: As part of a single‐arm phase II trial in a university hospital, patients with advanced pancreatic adenocarcinoma were treated with weekly ω‐3FA–rich intravenous infusion (Lipidem [B. Braun Melsungen AG, Melsungen, Germany]: up to 100 g/wk) plus gemcitabine chemotherapy until withdrawal or tumor progression. Primary outcome measure was objective response rate. Changes in complement activity, which were a secondary outcome measure, were analyzed and relation to clinical outcome determined. Results: Twenty‐three patients were assessable for time to progression (TTP), overall survival (OS), and complement activity. No hypoactivity in alternative and classical pathways was demonstrated. Baseline MBL was low in 10 of 23 patients (43.5%). There was no difference in OS or TTP between low‐ and high‐baseline MBL patients. Of these 10 patients, 5 were classified as MBL responders. MBL responders had a tendency toward improved OS over nonresponders (8.9 vs 4.4 months, P = .07). MBL responders had significantly improved TTP over nonresponders (10.6 vs 5.3 months, P = .03). Conclusion: MBL restoration had an association with improved outcome in the cohort of patients with low MBL activity at baseline. The independent contribution of ω‐3FA to this effect warrants further investigation in the form of randomized clinical trials.     

Whey Peptide–Based Formulas With ω‐3 Fatty Acids Are Protective in Lipopolysaccharide‐Mediated Sepsis

Background: Sepsis and septic shock syndrome are among the leading causes of death in critically ill patients. Lipopolysaccharide (LPS) released by bacteria within the colon may translocate across a compromised epithelium, leading to oxidative stress, inflammation, sepsis, and eventually death. Methods: We examined the effects of a whey‐based enteral formula high in cysteine (antioxidant precursor) and the addition of ω‐3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), against a mouse model of LPS‐induced sepsis. Mice were fed either a whey‐based diet with EPA‐DHA (PAF), a whey‐based diet without EPA‐DHA (PSTD), or a casein‐based control diet (CONT). Results: Mice fed PAF or PSTD were protected against LPS‐induced weight loss. Whey‐based diets suppressed inflammatory cytokine release and oxidative stress damage. Furthermore, PAF and PSTD were able to inhibit autophagy, a mechanism in which the cell recycles damaged organelles. These anti‐inflammatory and antioxidative effects of PSTD and PAF resulted in decreased liver inflammation and intestinal damage and promoted protective microbiota within the intestines. Conclusions: These data suggest a clinical role for whey peptide–based diets in promoting healing and recovery in critically ill patients.     

Nutrition Modulation of Cardiotoxicity and Anticancer Efficacy Related to Doxorubicin Chemotherapy by Glutamine and ω‐3 Polyunsaturated Fatty Acids

Background: Doxorubicin (DOX) has been one of the most effective antitumor agents against a broad spectrum of malignancies. However, DOX‐induced cardiotoxicity forms the major cumulative dose‐limiting factor. Glutamine and ω‐3 polyunsaturated fatty acids (PUFAs) are putatively cardioprotective during various stresses and/or have potential chemosensitizing effects during cancer chemotherapy. Methods: Antitumor activity and cardiotoxicity of DOX treatment were evaluated simultaneously in a MatBIII mammary adenocarcinoma tumor‐bearing rat model treated with DOX (cumulative dose 12 mg/kg). Single or combined treatment of parenteral glutamine (0.35 g/kg) and ω‐3 PUFAs (0.19 g/kg eicosapentaenoic acid and 0.18 g/kg docosahexaenoic acid) was administered every other day, starting 6 days before chemotherapy initiation until the end of study (day 50). Results: Glutamine alone significantly prevented DOX‐related deterioration of cardiac function, reduced serum cardiac troponin I levels, and diminished cardiac lipid peroxidation while not affecting tumor inhibition kinetics. Single ω‐3 PUFA treatment significantly enhanced antitumor activity of DOX associated with intensified tumoral oxidative stress and enhanced tumoral DOX concentration while not potentiating cardiac dysfunction or increasing cardiac oxidative stress. Intriguingly, providing glutamine and ω‐3 PUFAs together did not consistently confer a greater benefit; conversely, individual benefits on cardiotoxicity and chemosensitization were mostly attenuated or completely lost when combined. Conclusions: Our data demonstrate an interesting differentiality or even dichotomy in the response of tumor and host to single parenteral glutamine and ω‐3 PUFA treatments. The intriguing glutamine × ω‐3 PUFA interaction observed draws into question the common assumption that there are additive benefits of combinations of nutrients that are beneficial on an individual basis.     

Dietary Fish Oil Aggravates Paracetamol‐Induced Liver Injury in Mice

Background: Paracetamol (APAP) hepatotoxicity remains the leading cause of drug‐induced liver failure. Fish oil, which contains ω‐3 fatty acids, has demonstrated therapeutic efficacy in several models of liver disease. Evidence for its use in APAP intoxication, however, is conflicting. The effects of fish oil supplementation on APAP‐induced liver failure were investigated. Methods: Ten C57BL6/J mice were fed a diet based on menhaden fish oil (MEN) or soybean oil (SOY) for 3 weeks followed by APAP intoxication. In a second experiment, the prefeeding period was reduced to 5 days. In a third experiment, 10 mice received the study diets for 3 weeks, after which they received chronic, low‐dose APAP administration for another 4 weeks. Finally, 10 mice received oral parenteral nutrition supplemented with either intravenous (IV) soybean‐based or fish oil–based lipid emulsion for 19 days, followed by APAP intoxication. Results: The extent of hepatocellular necrosis (3.8 ± 0.2 vs 2.8 ± 0.2; P = .021) and serum alanine aminotransferase values (2807 ± 785 vs 554 ± 141 IU/L; P = .048) were significantly elevated in mice fed a MEN diet compared with SOY‐diet fed controls. Long‐term, low‐dose APAP administration did not lead to liver injury irrespective of study diet. Pretreatment with soybean‐ or fish oil–based IV lipid emulsions followed by APAP intoxication demonstrated no significant differences in hepatic injury between groups. Conclusion: Within therapeutic ranges, APAP is harmless to the liver irrespective of dietary fat composition. IV use of fish oil did not increase APAP‐induced hepatotoxicity, but animals fed a fish oil–based diet were more susceptible, rather than resistant, to APAP‐induced hepatotoxicity.     

Incorporating omega‐3 in the food chain – why,where and how?

Summary It has been recognised for decades that high fat intakes are not conducive to good health and, more recently, that the fatty acid profile of the diet (sometimes referred to as fat quality) is also important. Fat intake as a proportion of total food energy has declined over recent years in line with recommendations. Although there have been changes in the types of fats consumed and a fall in the total intake of saturates towards the recommended level, there is still room for improvement. The proportion of energy derived from saturates is still too high in most EU countries. The recommended level is 10% or less of total energy (<11% total food energy) but data show that only two Member States consume 12% or less of total energy as saturates. As the main factor determining serum cholesterol is the amount of saturates in the diet, there are heart health benefits to be gained from achieving a reduction. Meanwhile, research investigating the promise of health benefits linked to increased consumption of n‐6 polyunsaturated fatty acids, monounsaturates and long‐chain n‐3 (omega‐3) polyunsaturates has expanded our knowledge of the health effects of these fatty acids in our diets. Attempts to modify dietary fatty acid profile started with meat and dairy products but developments throughout the food chain have now taken place, such as production of lower fat meats, meat products and spreads; low‐fat milks and dairy products, and a variety of manufactured foods with a reduced fat content and enhanced fatty acid profile. Together these initiatives have led to a fall in saturates intake and improvements in the overall fatty acid profile of our diets, although targets have generally not been met as yet. More recently there have been recommendations to increase our intake of fish, the primary dietary source of long‐chain n‐3 fatty acids. However, the latter has been accompanied by environmental concerns about the safety and sustainability of fish and fish oil supplies. Dietary sources of these long chain n‐3 fatty acids are very limited, oily fish being the only major source. Meanwhile, across Europe, associated with the increased prevalence of obesity and related morbidities, health care costs have soared, exacerbated by the fact that people are living longer although these extra years are often spent in poor health. This has provoked a renewed and reinvigorated search for dietary approaches to health promotion that can potentially be applied to the food supply at the population level. Exploring ways of enhancing the food supply with respect to long‐chain n‐3 fatty acids has been the focus of researchers associated with the EU‐funded Lipgene project. Possible routes include enrichment of meat and meat products through standard animal husbandry techniques, enrichment of milk (either via the cows’ diet or during processing), and more controversially the development of transgenic plants capable of producing long‐chain n‐3 fatty acids, which could be used as a vehicle to introduce these important fatty acids into the food chain.     

3‐carboxy‐4‐methyl‐5‐propyl‐2‐furanpropanoic acid (CMPF): A metabolite identified after consumption of fish oil and fish

3‐carboxy‐4‐methyl‐5‐propyl‐2‐furanpropanoic acid (CMPF) is a known metabolite of furan fatty acids and was first referred to as a urofuran fatty acid, as it was found in urine of humans and other species after consumption of furan fatty acids or foods containing furan fatty acids. More recently, CMPF has been identified as a highly prominent metabolite following the consumption of fish oil, fish oil fractions and diets rich in fish, and can be regarded as biomarker of oil‐rich fish or fish oil intakes. As furan fatty acids are known to occur in fish and fish oil (at a low level), it is possible that the CMPF in plasma arises from these furan fatty acids. On a structural basis, this is a likely explanation rather than the CMPF being an actual metabolite of long‐chain marine omega‐3 fatty acids. Recent studies in high fat‐fed mice given purified CMPF suggest that CMPF might contribute to the improved metabolic effects observed following consumption of long‐chain marine omega‐3 fatty acids but much is still to be known about the relationships between CMPF and health.     

Parenteral but Not Enteral Omega‐3 Fatty Acids (Omegaven) Modulate Intestinal Regrowth After Massive Small Bowel Resection in Rats

Background: The purpose of the present study was to evaluate the effects of ω‐3 fatty acids (Omegaven) on early intestinal adaptation in rats with short bowel syndrome (SBS). Methods: Male Sprague‐Dawley rats were randomly assigned to 1 of 4 groups: sham rats underwent bowel transection; SBS rats underwent 75% bowel resection; SBS‐O ω‐3 rats underwent bowel resection and were treated with oral Omegaven given by gavage; and SBS‐I ω‐3 rats underwent bowel resection and were treated with Omegaven given intraperitoneally. Rats were killed on day 14. Parameters of intestinal adaptation (bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depths, cell proliferation and apoptosis) were determined at time of death. Real‐time polymerase chain reaction was used to determine the level of Bax and Bcl‐2 messenger RNA (mRNA). Statistical analysis was performed using Kruskal‐Wallis test followed by post hoc test, with P < .05 considered statistically significant. Results: Oral ω‐3 supplementation did not significantly change intestinal regrowth. In contrast, parenteral ω‐3 in rats that underwent resection resulted in higher bowel and mucosal weights, mucosal DNA and protein in ileum, villus height in ileum, crypt depth in jejunum and ileum, and greater rates of cell proliferation in jejunum and ileum compared with SBS animals. The initial decreased levels of apoptosis corresponded with the early decrease in Bax and increase in Bcl‐2 mRNA levels. Conclusions: Parenteral but not enteral Omegaven augments and accelerates structural bowel adaptation in a rat model of SBS. Increased cell proliferation and decreased apoptosis reflect increased cell turnover in Omegaven‐treated animals.     

Prefeeding With ω‐3 Fatty Acids Suppresses Inflammation Following Hemorrhagic Shock

Background: Hemorrhagic shock followed by resuscitation stimulates an inflammatory response. This study tests the hypothesis that prefeeding with fish oil rich in ω‐3 fatty acids (FAs) will attenuate that response. Methods: Male Sprague‐Dawley rats (n = 60; 350 ± 30 g) were randomly but unequally assigned to 3 groups: sham (n = 12), control (n = 24), and fish oil (n = 24). In the fish oil group, rat chow was supplemented with fish oil (600 mg/kg/d, 25% ω‐3 FA). Control and sham group diets were supplemented with corn oil. Under fluothane, hemorrhagic shock was induced, and arterial pressure was maintained at 25 to 30 mm Hg for 30 minutes. Resuscitation was carried out by giving 21 mL/kg lactated Ringer's solution and returning shed blood to the animal. Half of each group was killed at 30 minutes and at 4 hours postresuscitation. Liver samples were assayed for indicators of inflammation and heat shock protein 25 (Hsp25). Lung edema was measured. Results: All animals survived. At 30 minutes postresuscitation, expression of mRNA for inducible nitric oxide synthase (iNOS) was significantly elevated in the control group but normal in the fish oil group. At 4 hours, expression of mRNA for Hsp25 was significantly increased in the fish oil group. Lung edema index was significantly lower in the fish oil group than in either sham or control groups. Conclusions: Fish oil prefeeding in a rodent model of hemorrhagic shock was associated with increased liver mRNA expression of Hsp25, reduced liver mRNA expression of iNOS, and decreased lung edema. These findings support the validity of the study hypothesis.     

ω-3 Fatty acids have no impact on serum lactate levels after major gastric cancer surgery

Background: Preoperative and intraoperative nutrition support in patients undergoing major surgery results in decreased incidence of morbidity and mortality. Studies investigating the role of ω‐3 fatty acids in these patients are increasing. Some are focused on perfusion at the cellular level. This study was undertaken to address the effect of postoperative administration of ω‐3 fatty acids on cellular hypoperfusion associated with major gastric surgery. Methods: Twenty‐six patients undergoing gastric cancer surgery were randomly assigned to receive parenteral nutrition (PN) supplemented with a combination of ω‐6 and ω‐3 fatty acids (Omegaven, 0.2 g/kg/d; Lipovenoes 10%, 0.6 g/kg/d) or with ω‐6 fatty acid (Lipovenoes 10%, 0.8 g/kg/d) for 5 days. Blood samples were taken preoperatively, postoperative day 1, and on the last day of PN therapy (day 5). Results: Patients receiving ω‐3 and ω‐6 fatty acids showed neither lower serum lactate levels nor lower rates of complications compared with patients receiving ω‐6 only. There were no statistically significant differences between the groups in other biochemical parameters, complications, or length of hospital stay or mortality. Conclusion: PN with ω‐3 fatty acid supplementation does not have a significant impact on cellular hypoperfusion and lactate clearance after major gastric surgery.