Dietary PUFA Research Articles

Dietary fatty acids sex-specifically modulate guinea pig postnatal development via cortisol concentrations

Early ontogenetic periods and postnatal maturation in organisms are sex-specifically sensitive to hypothalamic-pituitary-adrenal (HPA)-axis activities, related glucocorticoid secretions, and their effects on energy balance and homeostasis. Dietary polyunsaturated (PUFAs) and saturated (SFAs) fatty acids potentially play a major role in this context because PUFAs positively affect HPA-axis functions and a shift towards SFAs may impair body homeostasis. Here we show that dietary PUFAs positively affect postnatal body mass gain and diminish negative glucocorticoid-effects on structural growth rates in male guinea pigs. In contrast, SFAs increased glucocorticoid concentrations, which positively affected testes size and testosterone concentrations in males, but limited their body mass gain and first year survival rate. No distinct diet-related effects were detectable on female growth rates. These results highlight the importance of PUFAs in balancing body homeostasis during male’s juvenile development, which clearly derived from a sex-specific energetic advantage of dietary PUFA intakes compared to SFAs.

The Efficacy of the Consumption of n-3 Polyunsaturated Fatty Acids for the Maintenance of Remission in Patients with Inflammatory Bowel Disease

The aim of the present study was to investigate the efficacy of the actual consuming n-3 PUFA for remission-maintenance in IBD patients. A questionnaire on the dietary habits of patients one month before hospitalization (Q1) was completed by 24 patients with IBD (10 ulcerative colitis (UC) subjects and 14 Crohn’s disease (CD) subjects) treated at our hospital. We educated the study subjects about an n-3 PUFA diet, and a follow-up survey (Q2) was conducted 6 to 12 months after discharge. Disease activity was evaluated using the International Organization for the Study of Inflammatory Bowel Disease (IOIBD) score and/or the Crohn’s Disease Activity Index (CDAI) score for CD and the partial UCDAI score without endoscopic evaluation for UC. Q1 showed that the average n-3 and n-6 PUFA intakes were 1673 ± 1651 mg and 9146 ± 5217 mg, respectively, and the average n-3/n-6 ratio was 0.27 ± 0.31. In Q2, the intake of n-3 PUFA was significantly higher (3671 ± 1684 mg, p < 0.001), whereas the n-6 PUFA intake decreased significantly (5217 ± 1973 mg, p < 0.001) compared to those in Q1. As a consequence, the dietary n-3/ n-6 ratio was significantly increased (0.87 ± 0.60, p < 0.001). Maintenance of the remission rate was significantly higher in IBD patients who complied with the n-3 diet, and these patients maintained a dietary n-3/n-6 ratio of 0.432 or higher (17 of 23 cases; 70.8%, p < 0.03) compared to that observed for IBD patients who did not comply with the diet. These results emphasize the importance of adjusting dietary PUFA and suggest that the n-3 diet may be effective in maintaining the remission of IBD.

Effect of Poly-Unsaturated Fatty Acids Fortification on Growth Performance, Survival, Fatty Acid Composition and Antioxidant Balance of Meagre, Argyrosomus regius Larvae

A total of 120 meagre, Argyrosomus regius, larvae (0.37 ± 0.02 g) were assigned to four treatments (three replicates each) to determine the optimum dietary level of PUFAs, at which there will be the best growth performance, feed utilization, fatty acids composition and antioxidant status. The treatments were a control group (fed a basal diet 3% PUFAs of total fatty acids) and another three groups fed PUFAs supplemented diets at levels 4.55, 6% and 7% for 21 days. The results indicated that increasing dietary PUFAs levels up to 4.5% significantly improved growth and survival compared to the control group. Feed intake, feed conversion ratio and protein utilization were significantly increased with 4.5% PUFAs followed by the control group. The results revealed significant differences in PUFAs among treatments and the best value was reported for the 4.5% PUFAs supplemented diet followed by the control. There is a significant increase in TBARs levels with increasing dietary PUFAs concentration. Meanwhile, the SOD and CAT activities decreased significantly with increasing PUFAs levels. However, TAS decreased significantly with higher PUFAS level (6%) only compared to other treatments. Therefore, the dietary requirements of A. regius larvae is 4.5% PUFAs of total fatty acids.

Apolipoprotein E gene polymorphism modifies fasting total cholesterol concentrations in response to replacement of dietary saturated with monounsaturated fatty acids in adults at moderate cardiovascular disease risk

BackgroundConsumption of ≤10% total energy from fat as saturated fatty acids (SFA) is recommended for cardiovascular disease risk reduction in the UK; however there is no clear guidance on the optimum replacement nutrient. Lipid-associated single-nucleotide polymorphisms (SNPs) have been shown to modify the lipid responses to dietary fat interventions. Hence, we performed a retrospective analysis in 120 participants from the Dietary Intervention and VAScular function (DIVAS) study to investigate whether lipoprotein lipase (LPL) and apolipoprotein E (APOE) SNPs modify the fasting lipid response to replacement of SFA with monounsaturated (MUFA) or n-6 polyunsaturated (PUFA) fatty acids.MethodsThe DIVAS study was a randomized, single-blinded, parallel dietary intervention study performed in adults with a moderate cardiovascular risk who received one of three isoenergetic diets rich in SFA, MUFA or n-6 PUFA for 16 weeks.ResultsAfter the 16-week intervention, a significant diet-gene interaction was observed for changes in fasting total cholesterol (P = 0.001). For the APOE SNP rs1064725, only TT homozygotes showed a significant reduction in total cholesterol after the MUFA diet (n = 33; −0.71 ± 1.88 mmol/l) compared to the SFA (n = 38; 0.34 ± 0.55 mmol/l) or n-6 PUFA diets (n = 37; −0.08 ± 0.73 mmol/l) (P = 0.004). None of the interactions were statistically significant for the other SNPs.ConclusionsIn summary, our findings have demonstrated a greater sensitivity of the APOE SNP rs1064725 to dietary fat composition, with a total cholesterol lowering effect observed following substitution of SFA with MUFA but not n-6 PUFA. Further large intervention studies incorporating prospective genotyping are required to confirm or refute our findings.Trial registrationThe trial was registered at www.clinicaltrials.gov as NCT01478958.

The effects of diets enriched in omega-3 polyunsaturated fatty acids on systemic vaccinia virus infection

Omega-3 polyunsaturated fatty acids (PUFA, n-3 fatty acids), the key components of fish and flaxseed oils, are increasingly consumed by the public because of their potential health benefits and are available by prescription for hypertriglyceridemia. However, numerous studies have shown that these compounds are immunoregulatory and immunosuppressive and thus may increase susceptibility to infection. In this study, we tested the effects of the amount of fat and the types of fatty acid in the diet on infection by vaccinia virus, an acute infection that begins in the respiratory tract and spreads by viremia to internal organs. Male C57Bl6 mice (~5 week old) were fed for 3 weeks prior to infection and continuing during infection and recovery one of the following: 1) a normal low fat (13% kcal) diet, 2) a low fat diet containing n-3 PUFAs, 3) a high fat (41% kcal) diet rich in n-3 PUFAs, 4) a high fat n-6 PUFA diet, or 5) a high fat monounsaturated diet. We found no statistically significant differences in the susceptibility of mice to viral infection, morbidity, viral organ titers, recovery time, or mortality with these diets, indicating that, over this approximately 6-week time period, dietary fats did not substantially affect responses to poxviral infection.

The compositional and metabolic responses of gilthead seabream (Sparus aurata) to a gradient of dietary fish oil and associated n-3 long-chain PUFA content.

The replacement of fish oil (FO) with vegetable oil (VO) in feed formulations reduces the availability of n-3 long-chain PUFA (LC-PUFA) to marine fish such as gilthead seabream. The aim of this study was to examine compositional and physiological responses to a dietary gradient of n-3 LC-PUFA. Six iso-energetic and iso-nitrogenous diets (D1-D6) were fed to seabream, with the added oil being a blend of FO and VO to achieve a dietary gradient of n-3 LC-PUFA. Fish were sampled after 4 months feeding, to determine biochemical composition, tissue fatty acid concentrations and lipid metabolic gene expression. The results indicated a disturbance to lipid metabolism, with fat in the liver increased and fat deposits in the viscera reduced. Tissue fatty acid profiles were altered towards the fatty acid compositions of the diets. There was evidence of endogenous modification of dietary PUFA in the liver which correlated with the expression of fatty acid desaturase 2 (fads2). Expression of sterol regulatory element binding protein 1 (srebp1), fads2 and fatty acid synthase increased in the liver, whereas PPARα1 pathways appeared to be supressed by dietary VO in a concentration-dependent manner. The effects in lipogenic genes appear to become measurable in D1-D3, which agrees with the weight gain data suggesting that disturbances to energy metabolism and lipogenesis may be related to performance differences. These findings suggested that suppression of β-oxidation and stimulation of srebp1-mediated lipogenesis may play a role in contributing toward steatosis in fish fed n-3 LC-PUFA deficient diets.

Endotoxemia is modulated by quantity and quality of dietary fat in older adults.

Aging is an important determinant of the rate of atherosclerosis development, mainly through low-grade inflammation. Diet, and particularly its fat content, modulates the inflammatory response in fasting and postprandial states. We aimed to study the effects of dietary fat on endotoxemia in healthy older adults. Twenty healthy older adults were randomized to three diets, lasting three-weeks each, using a crossover design: 1. A Mediterranean diet enriched in MUFA with virgin olive oil. 2. An SFA-rich diet. 3. A low-fat high-carbohydrate diet enriched in n-3 PUFA (α-linolenic acid of plant origin) (CHO-PUFA diet). At the end of each period, after a 12-h fast, the subjects received a meal with a composition similar to the dietary period just completed. We determined the fasting and the postprandial plasma levels of lipopolysaccharide (LPS) and LPS-binding protein (LBP). In the fasting state, we observed lower LPS plasma levels after the consumption of the CHO-PUFA diet (P=0.046) in comparison with the consumption of the Med and SFA-rich diets. In the postprandial measurements, we observed a statistically significant increase in plasma levels of LPS (P=0.044) and a decrease in LBP (P=0.003) after the intake of the CHO-PUFA meal, whereas no postprandial changes were observed after the ingestion of the Med and SFA-rich meals. Our results, together with those obtained in a previous study, support the concept that the consumption of the Med Diet, in contrast to a low-fat PUFA diet, constitutes a more suitable dietary lifestyle for preventing the development of atherosclerosis in a population at risk, such as older adults.

Dietary PUFAs attenuate NLRP3 inflammasome activation via enhancing macrophage autophagy

Dietary PUFAs reduce atherosclerosis and macrophage inflammation, but how nucleotide-binding oligomerization domain leucine-rich repeat-containing receptor protein (NLRP3) inflammasome activation and autophagy influence PUFA-mediated atheroprotection is poorly understood. We fed Ldlr−/− mice diets containing 10% (calories) palm oil (PO) and 0.2% cholesterol, supplemented with an additional 10% of calories as PO, fish oil (FO), echium oil (EO, containing 18:4 n-3), or borage oil (BO, containing 18:3 n-6). Inflammasome activation, autophagic flux, and mitochondrial function were measured in peritoneal macrophages, blood monocytes, or liver from diet-fed mice. Compared with PO, dietary PUFAs (FO, EO, or BO) markedly inhibited inflammasome activation, shown by 1) less macrophage IL-1β secretion and caspase-1 cleavage in response to NLRP3 inflammasome activators, 2) less IL-1β secretion and caspase-1 cleavage from liver or hepatocytes in response to lipopolysaccharide (LPS), and 3) attenuated caspase-1 activity in blood monocytes. Furthermore, PUFA-enriched diets increased LC3-II expression in macrophage, aorta, and liver samples and reduced numbers of dysfunctional mitochondria in macrophages in response to LPS and palmitate, suggesting enhanced autophagic activation. Dietary PUFAs did not attenuate NLRP3 inflammasome activation in atg5-deficient macrophages, indicating that autophagic activation is critical for the PUFA-mediated inflammasome inactivation. In conclusion, dietary PUFAs reduce atherosclerosis, in part, by activation of macrophage autophagy and attenuation of NLRP3 inflammasome activation.

Polyunsaturated fatty acids in stream food webs – high dissimilarity among producers and consumers

Abstract Streams and rivers provide crucial sources of long‐chain polyunsaturated fatty acids (LC‐PUFA, a subset of PUFA with ≥20 C in their acyl chains) for freshwater and terrestrial animals. LC‐PUFA are primarily produced by particular algal taxa and are subsequently transferred to fish and higher consumers, including humans. Although research on the trophic transfer of LC‐PUFA in streams is very limited, studies on the PUFA composition of organisms at various trophic levels within stream food webs are well documented. Here, we systematically analyze the literature to synthesise LC‐PUFA distribution and retention in stream ecosystems. In general, stream food webs are highly enriched in omega‐3 LC‐PUFA, in particular eicosapentaenoic acid (EPA, 20:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3). Algae from temperate rivers had more EPA compared with algae from subtropical rivers. Stream invertebrates from both temperate and subtropical rivers preferentially retain algal EPA and their PUFA tend to vary with algal PUFA. Invertebrates may be capable of regulating their fatty acid (FA) composition, but this ability is limited, to the extent that they must obtain physiologically important LC‐PUFA primarily from algae. DHA is selectively and highly retained in all fish taxa irrespective of their feeding sites (i.e. temperate or subtropical rivers). However, DHA content is variable among stream fish taxa and is likely linked to resource utilisation and their endogenous metabolism. Freshwater salmonids have a very high DHA content, which suggests they preferentially retain this FA or biosynthesise it from EPA. The PUFA profiles of other fish taxa more closely reflect their dietary PUFA supply. However, so far very few studies have considered the differences in the PUFA biosynthesis of fish taxa in rivers or compared the dietary PUFA effect on different fish taxa. The supply of LC‐PUFA from streams and rivers is known to be affected by altered light availability, greater nutrient inputs and other anthropogenic activities, and any decrease in algal LC‐PUFA production will negatively affect the consumers that are nutritionally dependent on these molecules. Further investigations are needed to understand how environmental changes affect LC‐PUFA production and retention in stream ecosystems, and how to protect streams from threats to this essential ecosystem service.

Dietary fatty acids and lipoproteins on progression of age-related macular degeneration

Age-related macular degeneration (AMD) is a medical condition of central loss vision and blindness. Numerous studies have revealed that changes on certain dietary fatty acids (FAs) could have useful for AMD management. This review summarizes the effects of dietary omega-3 long-chain PUFAs, MUFAs, and SFAs, and lipoproteins on AMD. Findings are consistent with the beneficial role of dietary omega-3 long-chain PUFAs, while the effects of dietary MUFAs and SFAs appeared to be ambiguous with respect to the possible protection from MUFAs and to the possible adverse impact from SFAs on AMD. Some of the pathological mechanisms associated with lipoproteins on AMD share those observed previously in cardiovascular diseases. It was also noticed that the effects of FAs in the diet and lipoprotein on AMD could be modulated by genetic variants. From a population health perspective, the findings of this review are in favour of omega-3 long-chain FAs recommendations in a preventive and therapeutic regimen to attain lower AMD occurrence and progression rates. Additional long-term and short-term nutrigenomic studies are required to clearly establish the role and the relevance of interaction of dietary FAs, lipoproteins, and genes in the genesis and progression of AMD.

Omega-3 Fatty Acids Supplementation did not Improve Cardiometabolic Benefits of 16 Weeks of Exercise Training

PURPOSE: To determine if supplementation with omega-3 polyunsaturated fatty acids (omega-3 PUFA) either as enriched milk or capsules would improve the benefits of an aerobic exercise training program in the health of metabolic syndrome (MSyn) patients. METHODS: Four groups of MSyn patients were enrolled, in a 16-week high intensity interval training program combined with n3-PUFA supplementation administered in a double-blind randomized design. Thirty six MSyn patients ingested during the training program 500 mL of milk daily, either enriched with 275 mg of omega-3PUFA or, semi-skim milk as placebo. Another 40 MSyn patients received capsules containing either 846 mg of omega-3PUFA or soybean oil as placebo. Before and after intervention, MSyn components (i.e., waist circumference, blood pressure, blood glucose, triglycerides and HDL concentrations), composite MSyn Z-score, cardiovascular risk factors (total cholesterol (TC) and LDL), glucose metabolism markers (HbA1c and HOMA), body weight and composition, and cardiorespiratory fitness (peak oxygen consumption; VO2PEAK) and maximal rate of fat oxidation (FOMAX) were assessed. Data was analyzed using split plot ANCOVA (Time x Treatment) controlling for body weight loss. RESULTS: From the MSyn components, only blood pressure decreased significantly (P<0.001) after the exercise program without further benefit from omega-3 PUFA in any ingestion modality (P=0.340). MSyn Z-score, TC and LDL decreased significantly after training (P<0.001, P=0.016 and P=0.003, respectively) without differences among groups (P= 0.091, P=0.095 and P=0.156, respectively). HbA1c, HOMA and body weight did not change in any group (P=0.087, P=0.762, and P=0.203, respectively). However total fat mass decreased in all groups (P<0.001) without differences among treatments (P=0.942). VO2PEAK and FOMAX improved (P<0.001) in a similar fashion among experimental groups (P=0.651 and P=0.333, respectively). CONCLUSIONS: Sixteen weeks of dietary omega-3 PUFA supplementation either administered as functional food (enriched skim milk) or at a higher dose provided in capsules, did not further enhance the benefits of high intensity interval training in a group of metabolic syndrome patients.

Fatty acid intake and erythrocyte fatty acid profile in women with breast, ovarian and cervical cancers

Summary Aim To assess dietary fat and fatty acid (FA) intakes and to correlate it with red blood cell (RBC) FA composition in women with newly diagnosed breast, cervical and ovarian cancer. Methods 185 women who were newly diagnosed with breast, cervical or ovarian cancer were recruited for the study and dietary information was obtained using food frequency questionnaires. RBC fatty acid composition was analyzed in a subset of 96 women with cancers (35 breast cancer, 31 cervical cancer and 30 ovarian cancer) and 56 age-matched controls. Results Subjects with malignancies were seen to consume lower amounts of fat and higher amounts of carbohydrates compared with controls. While the intakes of saturated fatty acids (SFA) were similar across the groups, The intakes of PUFA, specifically linoleic acid (LA, 18:2 n-6) and long chain n-3 PUFA (LC n-3 PUFA) were significantly lower (p Conclusion The study shows a good correlation between dietary PUFA intakes and RBC PUFA composition, and suggests that elongation of fatty acids is significantly affected in cancer such that it favours the formation of pro-inflammatory n-6 PUFA while repressing the formation of anti-inflammatory n-3 PUFAs.

Dietary and genetic influences on hemostasis in a Yup'ik Alaska Native population.

Fish and marine animals are important components of the subsistence diet of Alaska Native people, resulting in a high ω3 PUFA intake. The historical record for circumpolar populations highlights a tendency for facile bleeding, possibly related to ω3 PUFA effects on platelet activation and/or vitamin K-dependent clotting factors. To evaluate these two scenarios in Yup’ik people of southwestern Alaska, we examined the association between dietary ω3 PUFA intake and activities of clotting factor II, V, fibrinogen, PT, INR, PTT, and sP-selectin in 733 study participants, using the nitrogen isotope ratio of red blood cells as a biomarker of ω3 PUFA consumption. sP-selectin alone correlated strongly and inversely with ω3 PUFA consumption. Approximately 36% of study participants exhibited PIVKA-II values above the threshold of 2 ng/ml, indicative of low vitamin K status. To assess genetic influences on vitamin K status, study participants were genotyped for common vitamin K cycle polymorphisms in VKORC1, GGCX and CYP4F2. Only CYP4F2*3 associated significantly with vitamin K status, for both acute (plasma vitamin K) and long-term (PIVKA-II) measures. These findings suggest: (i) a primary association of ω3 PUFAs on platelet activation, as opposed to vitamin K-dependent clotting factor activity, (ii) that reduced CYP4F2 enzyme activity associates with vitamin K status. We conclude that high ω3 PUFA intake promotes an anti-platelet effect and speculate that the high frequency of the CYP4F2*3 allele in Yup’ik people (~45%) evolved in response to a need to conserve body stores of vitamin K due to environmental limitations on its availability.

Abstract 41: Omega-6 Fatty Acid Biomarkers and Incident Type 2 Diabetes: A Pooled Analysis of 20 Cohort Studies

Background: Emerging evidence suggests that dietary omega-6 polyunsaturated fatty acids (n-6 PUFA) plays a role in the primary prevention of type 2 diabetes (T2D). Aims: To evaluate the relation between blood and adipose tissue levels of n-6 PUFA and incident T2D, including n-6 linoleic acid (LA), the major dietary PUFA abundant in vegetable oils, and n-6 arachidonic acid (AA), a key precursor of endogenous metabolites that modulate glucose metabolism and inflammation. Methods: A global consortium of 20 prospective cohort studies identified by February 2016. Each study measured LA and AA at study baseline among adults&gt;18y without prevalent T2D, and assessed the association of n-6 PUFA biomarkers and T2D risk prospectively using individual-level data, using a pre-specified analytic plan and harmonized exposures, covariates, and effect modifiers. Findings were centrally pooled using fixed-effects meta-analysis. Results: 39,740 men and women from 10 countries were included (range of cohort means, age, 49-76y, and BMI, 25.0-28.1kg/m 2 ), with 4,347 incident cases of T2D observed during follow-up. In continuous multivariate-adjusted analyses, higher LA was associated with 36% lower risk of T2D (RR,0.64, 95% CI,0.59-0.71, P&lt;0.001, I 2 =49%, Figure 1A ) per interquintile range. Similar inverse associations were observed for LA measured in different fractions, and in sensitivity analysis using random effects model. Levels of AA were not associated with T2D risk overall and in studies grouped by different biomarker fractions except total plasma (per interquintile RR=0.74, 95% CI=0.62-0.88, P&lt;0.001, Figure 1B ). The relations of LA and AA with T2D were not significantly modified by age, BMI, sex, race, aspirin use, n-3 PUFA biomarker, or FADS genetic variants ( P ≥ 0.13 for each). Conclusion: Higher blood and adipose tissue LA levels, biomarkers of the major dietary PUFA, were associated with lower risk of T2D among free-living populations worldwide. There was little evidence that AA levels were appreciably associated with risk of T2D.

Impact of dietary precursor ALA versus preformed DHA on fatty acid profiles of eggs, liver and adipose tissue and expression of genes associated with hepatic lipid metabolism in laying hens

Dietary omega-3 polyunsaturated fatty acids (n-3 PUFA), including alpha-linolenic acid (ALA) and preformed longer chain PUFA (LCPUFA, particularly docosahexaenoic acid, DHA) differ in their egg LCPUFA enrichment efficiency. However, mechanisms leading to these differences are unclear. To this end, omega-3 PUFA contents in different lipid classes, including triacylglycerol (TAG) and total phospholipid (PL) in yolk, liver and adipose, as well as the expression of key hepatic enzymes in lipid metabolism were evaluated in laying hens in response to changes in dietary supply. Seventy Lohmann hens (n=10/treatment) consumed either a control diet (0.03% total omega-3 PUFA), or the control with supplementation (0.20%, 0.40% and 0.60% total omega-3 PUFA) from either flaxseed oil or algal product, as sources of ALA (precursor) or DHA (preformed), respectively. The study was arranged in a completely randomized design, and data were analyzed using the Proc Mixed procedure of SAS. ALA accumulated as a function of intake (P<0.0001) in total and lipid classes of yolk, liver and adipose (TAG only) for ALA- and DHA-fed hens. Unlike flaxseed oil, preformed-DHA contributed to greater (P<0.0001) accumulation of LCPUFA in yolk total PL and TAG pool, as well as adipose TAG. This may relate to elevated (P<0.0001) expression of acyl-CoA synthetase (ACSL1). No difference in hepatic EPA level in total lipids was noted between both treatment groups; EPAliver=2.1493x−0.0064; R2=0.70, P<0.0001 (x=dietary omega-3 PUFA). The latter result may highlight the role of hepatic EPA in the regulation of LCPUFA metabolism in laying hens.

Effects of diets supplemented with n–3 or n–6 PUFA on pig muscle lipid metabolites measured by non-targeted LC–MS lipidomic profiling

UPLC-ESI-QTOF-MS was applied for investigation of diet effects on lipid metabolites in muscle of Landrace pigs that were fed n–3 or n–6 PUFA supplemented diets. In total, over 1200 lipid metabolites were detected in pig muscle, and 187 lipids were significantly different between the diet groups. The fold-change (FC) values were much higher (up to 29) for lipid metabolites in the pig muscle of n–3 PUFA compared with those in the n–6 PUFA group. The n–3/n–6 PUFA diet intervention mainly appeared to affect fatty acids within the lipid metabolites and did not appear to alter the lipid class distribution. The results of the LC–MS profiling were reflected in GC-FID-based single fatty acid profiling of the muscle phospholipids and triglycerides. The findings show that there is a discrepancy between the high number of dietary-based different lipid metabolites and the low dietary effects on the expression of lipogenic proteins in pig muscle. In conclusion, pig muscle lipid metabolism after being fed different PUFA diets can be elucidated by using a combination of lipidomics studies and functional genomic approaches.

Compensatory induction of Fads1 gene expression in heterozygous Fads2-null mice and by diet with a high n-6/n-3 PUFA ratio

In mammals, because they share a single synthetic pathway, n-6/n-3 ratios of dietary PUFAs impact tissue arachidonic acid (ARA) and DHA content. Likewise, SNPs in the human fatty acid desaturase (FADS) gene cluster impact tissue ARA and DHA. Here we tested the feasibility of using heterozygous Fads2-null-mice (HET) as an animal model of human FADS polymorphisms. WT and HET mice were fed diets with linoleate/α-linolenate ratios of 1:1, 7:1, and 44:1 at 7% of diet. In WT liver, ARA and DHA in phospholipids varied >2× among dietary groups, reflecting precursor ratios. Unexpectedly, ARA content was only <10% lower in HET than in WT livers, when fed the 44:1 diet, likely due to increased Fads1 mRNA in response to reduced Fads2 mRNA in HET. Consistent with the RNA data, C20:3n-6, which is elevated in minor FADS haplotypes in humans, was lower in HET than WT. Diet and genotype had little effect on brain PUFAs even though brain Fads2 mRNA was low in HET. No differences in cytokine mRNA were found among groups under unstimulated conditions. In conclusion, differential PUFA profiles between HET mice and human FADS SNPs suggest low expression of both FADS1 and 2 genes in human minor haplotypes.

Modulation of brain PUFA content in different experimental models of mice

The relative amounts of arachidonic acid (AA) and docosahexaenoic acid (DHA) govern the different functions of the brain. Their brain levels depend on structures considered, on fatty acid dietary supply and the age of animals. To have a better overview of the different models available in the literature we here compared the brain fatty acid composition in various mice models (C57BL/6J, CD1, Fat-1, SAMP8 mice) fed with different n-3 PUFA diets (deficient, balanced, enriched) in adults and aged animals. Our results demonstrated that brain AA and DHA content is 1) structure-dependent; 2) strain-specific; 3) differently affected by dietary approaches when compared to genetic model of PUFA modulation; 4) different in n-3 PUFA deficient aged C57BL6/J when compared to SAMP8 mouse model of aging. From these experiments, we highlight the difficulty to compare results obtained in different mouse models, different strains, different brain regions and different ages.

Sex-specific effects of dietary fatty acids on saliva cortisol and social behavior in guinea pigs under different social environmental conditions.

BackgroundUnbalanced dietary intakes of saturated (SFAs) and polyunsaturated (PUFAs) fatty acids can profoundly influence the hypothalamic-pituitary-adrenal (HPA)-axis and glucocorticoid secretions in relation to behavioral performances. The beneficial effects of higher dietary PUFA intakes and PUFA:SFA ratios may also affect social interactions and social-living per se, where adequate physiological and behavioral responses are essential to cope with unstable social environmental conditions.MethodsEffects of diets high in PUFAs or SFAs and a control diet were investigated in male and female guinea pigs after 60 days of supplementation. Plasma fatty acid patterns served as an indicator of the general fatty acid status. HPA-axis activities, determined by measuring saliva cortisol concentrations, social behaviors, and hierarchy ranks were analyzed during group housing of established single-sexed groups and during challenging social confrontations with unfamiliar individuals of the other groups.ResultsThe plasma PUFA:SFA ratio was highest in PUFA supplemented animals, with female levels significantly exceeding males, and lowest in SFA animals. SFA males and females showed increased saliva cortisol levels and decreased aggressiveness during group housing, while sociopositive behaviors were lowest in PUFA males. Males generally showed higher cortisol increases in response to the challenging social confrontations with unfamiliar individuals than females. While increasing cortisol concentrations were detected in control and PUFA animals, no such effect was found in SFA animals. During social confrontations, PUFA males showed higher levels of agonistic and sociopositive behaviors and also gained higher dominance ranks among males, which was not detected for females.ConclusionsWhile SFAs seemingly impaired cortisol responses and social behaviors, PUFAs enabled adequate behavioral responses in male individuals under stressful new social environmental conditions. This sex-specific effect was possibly related to a general sex difference in the n-3 PUFA bioavailability and cortisol responses, which may indicate that males are more susceptible to changing environmental conditions, and shows how dietary fatty acids can shape social systems.Electronic supplementary materialThe online version of this article (doi:10.1186/s13293-016-0107-5) contains supplementary material, which is available to authorized users.

Smoking and red blood cell phospholipid membrane fatty acids

Smoking is associated with lower n-3 long chain polyunsaturated fatty acids (LCPUFA) concentrations; however, limited studies have accounted for dietary PUFA intake or whether tobacco dose or smoking duration influences this association. We measured red blood cell phospholipid (RBC) membrane concentrations of fatty acids in 126 current smokers, 311 former smokers, and 461 never smokers using gas liquid chromatography and tandem mass spectrometry. Smokers had lower RBC membrane percentages of total n-3 LCPUFAs compared to former smokers or never smokers (median percent: 5.46, [interquartile range (IQR) 4.52, 6.28] versus 6.39; [IQR: 5.18, 7.85] versus 6.59; [IQR 5.34, 8.01]) (p<0.001) and this association remained after adjusting for dietary PUFA intake. Duration of smoking and cigarettes per day were not associated with RBC membrane n-3 LCPUFA differences. Smoking is associated with lower n-3 LCPUFA RBC membrane percentages and this association was not influenced by diet or smoking dose or duration.