Mechanisms underlying the immunomodulatory effects of n-3 PUFA. Proc Nutr Soc. 2010;69:311-315. [PMID: 20546643 DOI: 10.1017/s0029665110001837]

Pharmaconutrition: Which substrates?

With the term "pharmaconutrition" or "immunonutrition" is intended the use of specific nutritional substrates having the ability of modulating specific mechanisms involved in several immune and inflammatory pathways. To achieve these goals, these substrates have to be administered with over physiologic dose. Glutamine and omega-3 polyunsaturated fatty acids, used as single substrate, did not show clear clinical advantages on solid endpoints such as postoperative complications. Despite several multiple substrate enteral feeds are available on the market, very few of them have been tested in randomized clinical trial to prove efficacy. The most extensive investigated formulation is a combination of arginine, omega-3 fatty acids, ribonucleic acid with or without glutamine. Several meta-analyses of randomized clinical trials have been conducted to compare the effects of enteral immunonutrition with control diets on post-surgical morbidity. The results consistently showed that the use of enteral multiple substrate formulas significantly reduced infectious complications and duration of hospitalization. In a more contemporary view, pharmaconutrition should be tested more accurately in the contest of enhanced recovery programs, during neoadjuvant chemotherapy, and in the prehabilitation setting.

Recurrent Acute Otitis Media Could Be Related to the Pro-Inflammatory State That Causes an Incorrect Diet

Introduction: Acute Otitis Media (AOM) is the most commonly-occurring bacterial complication in childhood. After making certain corrections to the patients’ dietary habits, which we found to be excessively high in animal-based and industrially-processed foods, we observed a significant reduction in recurrent colds and their bacterial complications. We promote an original way of treating these diseases, since until now the conventional treatment is based on pharmacological and surgical treatment. From our point of view, the mucosa that covers the entire ENT area is in a pro-inflammatory and hyper-reactive state, as a consequence of the alterations produced by an inadequate diet. For us there is no difference in the nutritional treatment of the different mucous membranes that cover the ENT area. The purpose of the study was to assess the effects of the Traditional Mediterranean Diet (TMD) on patients diagnosed with Recurring Acute Otitis Media (RAOM). Methods: prospective pre-postest comparison study with 48 girls and 42 boys aged 1–5 years, each of whom had been and included on the 1-year programme “Learning to eat the Mediterranean Way”, designed to encourage the adoption of the TMD. We studied clinical and therapeutic variables and various anthropometric parameters. Results: all the symptomatic indicators studied (number and intensity of episodes of otitis and emergency admissions) showed a positive and statistically significant evolution in RAOM. By the end of the study, none of the patients met the criteria for classification as RAOM, and 60% percent of patients did not present any further episodes of AOM. In line with the above, the use of anti-microbial drugs and symptomatic treatments reduced considerably; the use of antibiotics dropped from 4.30 occasions/patient/year, to 0.66 (p < 0.001), and the used of symptomatic treatments dropped from 7.63 to 2.75 (p < 0.001). The level of family satisfaction was very high. Conclusions: the adoption of the Traditional Mediterranean Diet has been demonstrated to significantly reduce occurrence of acute otitis media and may contribute to the treatment of patients diagnosed with recurrent acute otitis media.

Effects of the Traditional Mediterranean Diet in Childhood Recurrent Acute Rhinosinusitis

Introduction: There are more and more studies that demonstrate the anti-inflammatory effects of the traditional Mediterranean diet (TMD). The aim of the study was to assess the effects of an intervention with the TMD in patients with recurrent acute and chronic rhinosinusitis. Material and Methods: We performed a pretest–posttest comparison study in 114 patients (56 girls and 58 boys) aged one to five years who had three or more acute rhinosinusitis episodes in the period of 1 year. They were included for a year in the nutritional program “Learning to eat from the Mediterranean”. The anthropometric, clinical, and therapeutic characteristics were studied. Results: All the studied indicators showed a positive and statistically significant evolution. Of the patients, 53.5% did not have any episode of acute rhinosinusitis, and 26.3% had only one, compared to the 3.37 they had on average in the previous year. The use of antibiotics decreased by 87.6%. The degree of satisfaction of the families was very high. The Mediterranean Diet Quality Index (KIDMED) that assesses the quality of the TMD rose from 7.7 to 11 points. Conclusions: The adoption of the TMD could have promising effects in the prevention and treatment of recurrent acute and chronic rhinosinusitis, limiting the pharmacological and surgical intervention in many of these patients.

The Role of Lipidomics in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental syndrome commonly diagnosed in early childhood; it is usually characterized by impairment in reciprocal communication and speech, repetitive behaviors, and social withdrawal with loss in communication skills. Its development may be affected by a variety of environmental and genetic factors. Trained physicians diagnose and evaluate the severity of ASD based on clinical evaluations of observed behaviors. As such, this approach is inevitably dependent on the expertise and subjective assessment of those administering the clinical evaluations. There is a need to identify objective biological markers associated with diagnosis or clinical severity of the disorder. Several important issues and concerns exist regarding the diagnostic competence of the many abnormal plasma metabolites produced in the different biochemical pathways evaluated in individuals with ASD. The search for high-performing bio-analytes to diagnose and follow-up ASD development is still a major target in medicine. Dysregulation in the oxidative stress response and proinflammatory processes are major etiological causes of ASD pathogenesis. Furthermore, dicarboxylic acid metabolites, cholesterol-related metabolites, phospholipid-related metabolites, and lipid transporters and mediators are impaired in different pathological conditions that have a role in the ASD etiology. A mechanism may exist by which pro-oxidant environmental stressors and abnormal metabolites regulate clinical manifestations and development of ASD.

Effect of the Aqueous Extract of Lantana grisebachii Stuck Against Bioaccumulated Arsenic-Induced Oxidative and Lipid Dysfunction in Rat Splenocytes

Arsenic (As) is a worldwide immunotoxic agent that is in contaminated waters and consumed by mammals. Phytotherapy may counteract its harmful effects. Lantana grisebachii Stuck (LG, Verbenaceae) and its extract are proposed as protective, given vvits in vitro bioactivity. The aim was to determine the protective capacity of the aqueous LG extract on splenocytes exposed in vivo to arsenic. Splenocytes were obtained from an arsenicosis model (Wistar rats consuming orally 0 [control; C] or 5 mg/Kg/d of As) that received 0-100 mg/Kg/d of LG extract for 30 days. As content (total reflection X-ray fluorescence), fatty acid profile (gas chromatography), γ-glutamyl transpeptidase activity (Szasz method), peroxides (xylenol orange-based assay), and nitrites (Griess reaction) were then assayed in viable splenocytes. Data were analyzed with ANOVA and the Tukey's test (p < .05). It was observed that the splenocytes contained 2.2 mg/Kg of this elemental arsenic. With γ-glutamyl transpeptidase inhibition and consequent triggering of hydroperoxides (p < .05), it was observed to increase saturated fatty acids and alter lipid profiles. LG treatment avoided damaging effects with values similar to unexposed C (p < .05), and cellular arsenic concentration (p < .0001). In conclusion, the aqueous extract of L. grisebachii counteracted arsenic toxicity in rat splenocytes by preventing its cellular accumulation and induction of lipid and redox disturbances, which may impair immune function.

Eicosapentaenoic Acid Reduces Fecal Levels of Calprotectin and Prevents Relapse in Patients With Ulcerative Colitis

BACKGROUND & AIMS

High fecal levels of calprotectin indicate mucosal inflammation and have been shown to predict relapse in patients with ulcerative colitis (UC). Eicosapentaenoic acid (EPA), the major component of n-3 fish oil, has anti-inflammatory properties in patients with chronic inflammatory disorders. We performed a placebo-controlled trial of patients with UC at risk of relapse to determine the ability of the free fatty acid form of EPA (EPA-FFA) to reduce intestinal inflammation, using fecal level of calprotectin as a marker.

METHODS

From June 2014 to May 2016, 60 patients with UC with a partial Mayo score < 2 and fecal calprotectin ≥150 μg/g, in stable therapy for at least the 3 previous months, were randomly assigned to groups (1:1) given either EPA-FFA (500 mg, twice daily) or placebo for 6 months. A colonoscopy was performed at baseline. Clinical assessments and measurements of fecal calprotectin were made at baseline, at study months 3 and 6, or the time of clinical relapse. Patients with a relapse of UC underwent a second colonoscopy. The primary end point was a 100-point reduction in fecal levels of calprotectin at 6 months from the baseline value; the secondary end point was maintenance of clinical remission at 6 months.

RESULTS

The primary end point was achieved by 19 of 30 patients (63.3%) in the EPA-FFA group vs 4 of 30 patients (13.3%) in the placebo group (odds ratio, 12.0; 95% CI, 3.12-46.24; P < .001). The secondary end point was achieved by 23 of 30 patients (76.7%) in the EPA-FFA group vs 15 of 30 (50%) patients in the placebo group (OR, 3.29; 95% CI, 1.08-9.95; P = .035). No serious adverse events were observed.

CONCLUSIONS

In a placebo-controlled trial of 60 patients with UC, we found 6 months' administration of EPA-FFA to reduce fecal levels of calprotectin with no serious adverse events. This agent might be used to induce and maintain symptom-free remission in patients with UC. ClinicalTrials.gov number: NCT02179372.

Liquid Crystalline Nanostructures as PEGylated Reservoirs of Omega-3 Polyunsaturated Fatty Acids: Structural Insights toward Delivery Formulations against Neurodegenerative Disorders

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are bioactive lipids with considerable impact in medicine and nutrition. These compounds exert structuring effects on the cellular membrane organization, regulate the gene expression, and modulate various signaling cascades and metabolic processes. The purpose of the present work is to demonstrate the structural features of ω-3 PUFA-containing three-dimensional supramolecular lipid assemblies suitable for pharmaceutical applications that require soft porous carriers. We investigate the liquid crystalline structures formed upon mixing of eicosapentaenoic acid (EPA, 20:5) with the lyotropic nonlamellar lipid monoolein and the formation of multicompartment assemblies. Starting with the monoolein-based lipid cubic phase, double membrane vesicles, cubosome precursors, sponge-type particles (spongosomes), mixed intermediate nonlamellar structures, and multicompartment assemblies are obtained through self-assembly at different amphiphilic compositions. The dispersions containing spongosomes as well as nanocarriers with oil and vesicular compartments are stabilized by PEGylation of the lipid/water interfaces using a phospholipid with a poly(ethylene glycol) chain. The microstructures of the bulk mixtures were examined by cross-polarized light optical microscopy. The dispersed liquid crystalline structures and intermediate states were studied by small-angle X-ray scattering, cryogenic transmission electron microscopy, and quasielastic light scattering techniques. They established that PUFA influences the phase type and the sizes of the aqueous compartments of the liquid crystalline carriers. The resulting multicompartment systems and stealth nanosponges may serve as mesoporous reservoirs for coencapsulation of ω-3 PUFA (e.g., EPA) with water-insoluble drugs and hydrophilic macromolecules toward development of combination treatment strategies of neurodegenerative and other diseases.

The Imbalance between n-6/n-3 Polyunsaturated Fatty Acids and Inflammatory Bowel Disease: A Comprehensive Review and Future Therapeutic Perspectives

Eating habits have changed dramatically over the years, leading to an imbalance in the ratio of n-6/n-3 polyunsaturated fatty acids (PUFAs) in favour of n-6 PUFAs, particularly in the Western diet. Meanwhile, the incidence of inflammatory bowel disease (IBD) is increasing worldwide. Recent epidemiological data indicate the potential beneficial effect of n-3 PUFAs in ulcerative colitis (UC) prevention, whereas consumption of a higher ratio of n-6 PUFAs versus n-3 PUFAs has been associated with an increased UC incidence. The long-chain dietary n-3 PUFAs are the major components of n-3 fish oil and have been shown to have anti-inflammatory properties in several chronic inflammatory disorders, being involved in the regulation of immunological and inflammatory responses. Despite experimental evidence implying biological plausibility, clinical data are still controversial, especially in Crohn’s disease. Clinical trials of fish-oil derivatives in IBD have produced mixed results, showing beneficial effects, but failing to demonstrate a clear protective effect in preventing clinical relapse. Such data are insufficient to make a recommendation for the use of n-3 PUFAs in clinical practice. Here, we present the findings of a comprehensive literature search on the role of n-3 PUFAs in IBD development and treatment, and highlight new therapeutic perspectives.

Management of excessive inflammatory response in perioperative period of abdominal surgery

Perioperative excessive inflammation of abdominal surgery is caused by many perioperative factors, with activation of inflammatory cells, abnormal expression of cytokines and inflammatory mediators, and imbalance of proinflammatory and anti-inflammatory network system being the major factors. Since perioperative excessive inflammatory response can lead to a series of pathophysiological processes and even multiple organ dysfunction, it is an important factor to hinder the rehabilitation of patients after abdominal surgery. Therefore, management of excessive inflammatory response can control stress response, inhibit the excessive inflammatory reaction and its adverse reactions, reduce postoperative morbidity and mortality, and protect the function of major organs, thereby speeding up the recovery of patients. However, the understanding of the pathophysiological process and the management of excessive inflammatory response during the perioperative period are currently still in the infancy stage. This article systematically reviews the measures of managing the excessive inflammatory response during the perioperative period of abdominal surgery.

Immunoenhancing enteral and parenteral nutrition for gastrointestinal surgery: a multiple-treatments meta-analysis

OBJECTIVE

Frequentist meta-analyses have demonstrated that immunoenhancing parenteral nutrition (IMPN) and enteral nutrition (IMEN) reduce the incidence of infection and shorten the length of hospital stays compared with standard parenteral nutrition (SPN) and enteral nutrition (SEN). The aim of this study was to evaluate which kind of nutrition-SPN, SEN, IMPN, and IMEN-is most efficacious for reducing the incidence of complications after gastrointestinal surgery.

METHODS

An English literature search was carried out for randomized controlled trials published from January 1990 to February 2013 that evaluated the clinical efficacy of 4 kinds of nutrition after gastrointestinal surgery. A Bayesian framework was used to calculate the odds ratio between each treatment and the rank order.

RESULTS

Seventy-four studies (7572 participants) were included. According to the surface below the cumulative ranking curve (SUCRA) ordering from the best to the worst, IMEN was ranked first for reducing the incidence of 7 complications-any infection (SUCRA = 0.86), overall complication (SUCRA = 0.88), mortality (SUCRA = 0.81), wound infection (SUCRA = 0.79), intra-abdominal abscess (SUCRA = 0.98), anastomotic leak (SUCRA = 0.79), and sepsis (SUCRA = 0.92). Also, IMEN was ranked second for pneumonia and urinary tract infection. IMPN was ranked first for pneumonia (SUCRA = 0.81) and urinary tract infection (SUCRA = 0.86), third for mortality, and fourth for both intra-abdominal abscess and anastomotic leak. SPN showed an inferior efficacy for almost all outcomes.

CONCLUSIONS

This study suggests that IMEN outperformed other nutrition types for reducing complications and IMEN should be considered the best available option.

Clinical evidence for pharmaconutrition in major elective surgery

In recent years, standard nutrition preparations have been modified by adding specific nutrients, such as arginine, ω-3 fatty acids, glutamine, and others, which have been shown to upregulate host immune response, modulate inflammatory response, and improve protein synthesis after surgery. Most randomized trials and several meta-analyses have shown that perioperative administration of enteral arginine, ω-3 fatty acids, and nucleotides (immunonutrition) reduced infection rate and length of hospital stay in patients with upper and lower gastrointestinal (GI) cancer. The most pronounced benefits of immunonutrition were found in subgroups of high-risk and malnourished patients. Promising but not conclusive results have been found in non-GI surgery, especially in head and neck surgery and in cardiac surgery, but larger trials are required before recommending immunonutrition as a routine practice. Conflicting results on the real benefit of parenteral glutamine supplementation in patients undergoing elective major surgery have been published. In conclusion, enteral diets supplemented with specific nutrients significantly improved short-term outcome in patients with cancer undergoing elective GI surgery. Future research should investigate a molecular signaling pathway and identify specific mechanisms of action of immune-enhancing substrates.

Recent developments in lipid metabolism in ruminants – the role of fat in maintaining animal health and performance

Optimising farm animal performance has long been the key focus of worldwide livestock production research. Advances in the understanding of metabolism/phenotype associations have outlined the central role of the lipid metabolism of farm animals for economically relevant phenotypic traits, such as animal health (immune status, fertility/reproductive capacity, adaptability/metabolic flexibility, robustness, well being) and performance aspects (meat/milk quality and quantity) and have led to an extensive exploitation of lipid metabolism manipulation strategies (e.g. tailored nutritional regimes, alimentary/intravenous fat supplementation, rumen-protected fat feeding, hormone application). This contribution gives an overview of established concepts to tailor animals’ lipid metabolism and highlights novel strategies to expand these application-oriented approaches via improved analysis tools, omics-approaches, cell model systems and systems biology methods.

Hepatic transcriptome analysis of inter-family variability in flesh n-3 long-chain polyunsaturated fatty acid content in Atlantic salmon

Background

Genetic selection of Atlantic salmon families better adapted to alternative feed formulations containing high levels of vegetable ingredients has been suggested to ensure sustainable growth of aquaculture. The present study aimed to identify molecular pathways that could underlie phenotypic differences in flesh n-3 long-chain polyunsaturated fatty acid (LC-PUFA) levels when fish are fed vegetable oil diets. Liver transcriptome was analyzed and compared in four families presenting higher or lower n-3 LC-PUFA contents at two contrasting flesh total lipid levels.

Results

The main effect of n-3 LC-PUFA contents was in the expression of immune response genes (38% of all significantly affected genes), broadly implicated in the modulation of inflammatory processes and innate immune response. Although genetic evaluations of traits used in the breeding program revealed that the chosen families were not balanced for viral disease resistance, this did not fully explain the preponderance of immune response genes in the transcriptomic analysis. Employing stringent statistical analysis no lipid metabolism genes were detected as being significantly altered in liver when comparing families with high and low n-3 LC-PUFA flesh contents. However, relaxing the statistical analysis enabled identification of potentially relevant effects, further studied by RT-qPCR, in cholesterol biosynthesis, lipoprotein metabolism and lipid transport, as well as eicosanoid metabolism particularly affecting the lipoxygenase pathway. Total lipid level in flesh also showed an important effect on immune response and 8% of significantly affected genes related to lipid metabolism, including a fatty acyl elongase (elovl2), an acyl carrier protein and stearoyl-CoA desaturase.

Conclusions

Inter-family differences in n-3 LC-PUFA content could not be related to effects on lipid metabolism, including transcriptional modulation of the LC-PUFA biosynthesis pathway. An association was found between flesh adiposity and n-3 LC-PUFA in regulation of cholesterol biosynthesis, which was most likely explained by variation in tissue n-3 LC-PUFA levels regulating transcription of cholesterol metabolism genes through srebp2. A preponderance of immune response genes significantly affected by n-3 LC-PUFA contents could be potentially associated with disease resistance, possibly involving anti-inflammatory actions of tissue n-3 LC-PUFA through eicosanoid metabolism. This association may have been fortuitous, but it is important to clarify if this trait is included in future salmon breeding programmes.

Effect of n-3 fatty acids on immune function in broiler chickens

There is interest in the enrichment of poultry meat with long-chain n-3 polyunsaturated fatty acids in order to increase the consumption of these fatty acids by humans. However, there is concern that high levels of n-3 polyunsaturated fatty acids may have detrimental effects on immune function in chickens. The effect of feeding increasing levels of fish oil (FO) on immune function was investigated in broiler chickens. Three-week-old broilers were fed 1 of 4 wheat-soybean basal diets that contained 0, 30, 50, or 60 g/kg of FO until slaughter. At slaughter, samples of blood, bursa of Fabricius, spleen, and thymus were collected from each bird. A range of immune parameters, including immune tissue weight, immuno-phenotyping, phagocytosis, and cell proliferation, were assessed. The pattern of fatty acid incorporation reflected the fatty acid composition of the diet. The FO did not affect the weight of the spleen, but it did increase thymus weight when fed at 50 g/kg (P < 0.001). Fish oil also lowered bursal weights when fed at 50 or 60 g/kg (P < 0.001). There was no significant effect of FO on immune cell phenotypes in the spleen, thymus, bursa, or blood. Feeding 60 g/kg of FO significantly decreased the percentage of monocytes engaged in phagocytosis, but it increased their mean fluorescence intensity relative to that of broilers fed 50 g/kg of FO. Lymphocyte proliferation was significantly decreased after feeding broiler chickens diets rich in FO when expressed as division index or proliferation index, although there was no significant effect of FO on the percentage of divided cells. In conclusion, dietary n-3 polyunsaturated fatty acids decrease phagocytosis and lymphocyte proliferation in broiler chickens, highlighting the need for the poultry industry to consider the health status of poultry when poultry meat is being enriched with FO.

Randomized clinical trial of omega-3 fatty acid-supplemented enteral nutrition versus standard enteral nutrition in patients undergoing oesophagogastric cancer surgery

Background

Oesophagogastric cancer surgery is immunosuppressive. This may be modulated by omega-3 fatty acids (O-3FAs). The aim of this study was to assess the effect of perioperative O-3FAs on clinical outcome and immune function after oesophagogastric cancer surgery.

Methods

Patients undergoing subtotal oesophagectomy and total gastrectomy were recruited and allocated randomly to an O-3FA enteral immunoenhancing diet (IED) or standard enteral nutrition (SEN) for 7 days before and after surgery, or to postoperative supplementation alone (control group). Clinical outcome, fatty acid concentrations, and HLA-DR expression on monocytes and activated T lymphocytes were determined before and after operation.

Results

Of 221 patients recruited, 26 were excluded. Groups (IED, 66; SEN, 63; control, 66) were matched for age, malnutrition and co-morbidity. There were no differences in morbidity (P = 0·646), mortality (P = 1·000) or hospital stay (P = 0·701) between the groups. O-3FA concentrations were higher in the IED group after supplementation (P < 0·001). The ratio of omega-6 fatty acid to O-3FA was 1·9:1, 4·1:1 and 4·8:1 on the day before surgery in the IED, SEN and control groups (P < 0·001). There were no differences between the groups in HLA-DR expression in either monocytes (P = 0·538) or activated T lymphocytes (P = 0·204).

Conclusion

Despite a significant increase in plasma concentrations of O-3FA, immunonutrition with O-3FA did not affect overall HLA-DR expression on leucocytes or clinical outcome following oesophagogastric cancer surgery. Registration number: ISRCTN43730758 (http://www.controlled-trials.com). Copyright © 2012 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.

Effects of similar intakes of marine n-3 fatty acids from enriched food products and fish oil on cardiovascular risk markers in healthy human subjects

There is convincing evidence that consumption of fish and fish oil rich in long-chain (LC) n-3 PUFA (n-3 LCPUFA), EPA (20 : 5n-3) and DHA (22 : 6n-3) reduce the risk of CHD. The aim of the present study was to investigate whether n-3 LCPUFA-enriched food products provide similar beneficial effects as fish oil with regard to incorporation into plasma lipids and effects on cardiovascular risk markers. A parallel 7-week intervention trial was performed where 159 healthy men and women were randomised to consume either 34 g fish pâté (n 44), 500 ml fruit juice (n 38) or three capsules of concentrated fish oil (n 40), all contributing to a daily intake of approximately 1 g EPA and DHA. A fourth group did not receive any supplementation or food product and served as controls (n 37). Plasma fatty acid composition, serum lipids, and markers of inflammation and oxidative stress were measured. Compared with the control group, plasma n-3 LCPUFA and EPA:arachidonic acid ratio increased equally in all intervention groups. However, no significant changes in blood lipids and markers of inflammation and oxidative stress were observed. In conclusion, enriched fish pâté and fruit juice represent suitable delivery systems for n-3 LCPUFA. However, although the dose given is known to reduce the risk of CVD, no significant changes were observed on cardiovascular risk markers in this healthy population.

Dietary fatty acids affect the immune system in male mice sensitized to ovalbumin or vaccinated with influenza

PUFA are precursor molecules for eicosanoids such as leukotrienes and prostaglandins and may influence immune function through other mechanisms involving membranes, cell signaling, and gene expression. Immune-modulating properties of diets containing different oils [sunflower oil, rich in linoleic acid; linseed oil, rich in α-linolenic acid; salmon oil, rich in marine (n-3) PUFA; and beef tallow, rich in SFA] were investigated in an influenza-vaccination model, in which the delayed-type hypersensitivity (DTH) response was studied in C57BL/6 mice, and an ovalbumin (OVA)-sensitization model for experimental allergy in BALB/c mice. Six-week-old mice were fed the different diets for 7 wk. The first vaccination or OVA sensitization was given 2 wk after the start of the dietary intervention. In the mice vaccinated with influenza, the DTH response to the vaccine was significantly higher in mice fed the marine (n-3) PUFA diet compared to all other groups, indicating that these PUFA promote a T helper-1 response. In the OVA-sensitized mice, those fed the marine (n-3) PUFA diet had a less severe acute allergic skin response (ASR), suggesting that (n-3) PUFA lessen the T helper-2 response. Mice fed the SFA-rich diet had the most severe ASR, indicating that a diet with high levels of SFA may contribute to increased severity of allergic symptoms. Whereas significant differences in in vivo immune responses were measured, in vitro responses did not differ among the dietary groups. In conclusion, using 2 different models of immune responses demonstrates potential benefits from marine (n-3) PUFA.