The regiospecific characteristics of n-3 polyunsaturated fatty acids (PUFAs) in triacylglycerol (TAG) significantly affect the physicochemical and physiological properties of marine fish oils. In this study, the TAG molecular species composition and positional distributions of fatty acids were investigated in three marine fish species rich in omega-3 PUFAs (anchovy, tuna, and salmon). The regiospecific distribution of the fatty acids was measured with the allylmagnesium bromide (AMB) degradation method. The TAG compositions were analyzed with HPLC and the TAG molecular species were identified with APCI/MS. DHA was preferentially distributed at the sn-2 position of TAG, whereas EPA was evenly distributed along the glycerol backbone. The combinations of FAs, DDO, EOP, EPS, DSS, OOS, and PPS were the predominant TAG molecular species, and OOP, DOS, and DPoPo were the characteristic TAG molecules in the anchovy, salmon, and tuna, respectively. These data can be used to distinguish other marine fish species. The TAG composition categorized by TCN and ECN showed well-structured distributions, with double or triple peaks. These findings should greatly extend the use of marine fish oils in food production and may significantly affect the future development of the fish oil industry.

Purpose The aim of the current meta-analysis was to investigate the effect of increasing dietary ALA intake on the blood concentration of inflammatory markers including tumor necrosis factor (TNF), interleukin 6 (IL-6), C-reactive protein (CRP), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1) in adults. Methods After a systemic search on PubMed, Embase, and Cochrane library and bibliographies of relevant articles, 25 randomized controlled trials that met the inclusion criteria were identified. Results No significant effect of dietary ALA supplementation was observed on TNF (SMD:-0.03, 95% CI-0.36 to 0.29), IL-6 (SMD:-0.17, 95% CI-0.46 to 0.12), CRP (SMD:-0.06, 95% CI-0.24 to 0.12), sICAM-1 (SMD: -0.06, 95% CI-0.26 to 0.13), and sVCAM-1 (SMD: -0.24, 95% CI-0.56 to 0.09). Subgroup analysis revealed that increasing dietary ALA tends to elevate CRP concentration in healthy subjects. However, the null effect of ALA supplementation on other inflammatory markers was not changed in various subgroups, indicating that the results are stable. Meta-regression results revealed a negative relationship between the effect size on CRP and its baseline concentration. No significant publication bias was observed for all inflammatory markers as suggested by funnel plot and Begg's test. Conclusion Our meta-analysis did not find any beneficial effect of ALA supplementation on reducing inflammatory markers including TNF, IL-6, CRP, sICAM-1, and sVCAM-1. However, in healthy subjects, ALA supplementation might increase CRP concentration.

The sn-2 fatty acid composition of 180 commercial infant, follow-on and growing-up formulas with three fat sources (plant oil, cows' milk and goats' milk) was investigated and compared with mature human milk (MHM). Sn-2 fatty acids in formulas were mostly dependent on fat source and stage. Compared with MHM, all types of formulas contained lower levels of palmitic acid (PA), saturated fatty acid and long-chain polyunsaturated fatty acids (LC-PUFA), and higher levels of oleic acid (OA), linoleic acid (LA) and α-linolenic acid (LNA) at the sn-2 position. Even some formulas were supplemented with 1,3-dioleoyl-2-palmitoylglycerol, the proportions of relative PA at the sn-2 position in formulas were much lower than that in MHM. Moreover, formulas had higher proportions of relative OA, LA and LNA, and lower LC-PUFAs at the sn-2 position. This study indicated that there were significant differences in the positional distribution of fatty acids between formulas and MHM.

Trans-free mango kernel fat stearins and oleins were produced by three-stage acetone fractionation to achieve the sufficient utilization of fat. Fatty acid and triacylglycerol compositions, slip melting points, iodine values, micronutrient (tocopherol, sterol, and squalene) levels, as well as oxidative stability indexes of the fractions were analyzed to evaluate their qualities. The most abundant fatty acids in the stearins were saturated fatty acids (57.3-65.1%, mainly including palmitic, stearic, and arachidic acids), and the major triacylglycerols were symmetrical monounsaturated types (78.3-93.7%). The unique properties make the stearins show highest slip melting points 34.7-38.3 degrees C and oxidative stability indexes (12.0-14.2 h), and very suitable for the manufacturing of hard chocolate fats. The oleins contained high percentages of monounsaturated (48.3-53.7%) and polyunsaturated fatty acids (7.8-8.5%). Their oxidative stability indexes (6.3-6.7 h) were lower than the stearins but higher than common commercial oils. About 85.2% of tocopherol, 99.2% of sterol, and 79.2% of squalene were transferred to the liquids after fractionation, which could improve their antioxidant abilities. Further multiple linear regression analyses between oxidative stability indexes and fat compositions revealed that polyunsaturated fatty acid and sterol were the main factors that affect the oxidative stabilities of the fractions. The results suggested that the moderated refining techniques should be developed to retain more sterol to improve the oxidative stabilities and nutritive values of the fats.

Purpose: The aim of the present study was to investigate the effect of increasing dietary linoleic acid (LA) intake on the blood concentrations of inflammatory markers including cytokines, acute phase reactants and adhesion molecules in adults. Methods: We comprehensively searched PubMed, Embase and Cochrane Library for eligible studies. Overall, 30 randomized controlled studies involving 1377 subjects were included for meta-analysis. Results: No significant effect of higher LA intake was observed for cytokines: tumor necrosis factor (SMD: -0.01; 95% CI: -0.19 to 0.17), interleukin-6 (SMD: 0.11, 95% CI: -0.07 to 0.29), adiponectin (SMD: 0.17, 95% CI: -0.17 to 0.50) and monocyte chemoattractant protein 1 (SMD: 0.14, 95% CI: -0.33 to 0.60). Pooled effect size from 16 studies showed that the C-reactive protein (CRP) concentration was not significantly affected by increasing LA intake (SMD = 0.09, 95% CI: -0.05 to 0.24). However, subgroup and meta-regression analysis suggested that in subjects with a more profound increase of dietary LA intake, LA might increase the blood CRP level. Other acute phase reactants including fibrinogen and plasminogen activator inhibitor-1 and adhesion molecules were not significantly changed when LA was increased in diet. No significant heterogeneity or publication bias was observed, although only a limited number of eligible studies were included for some markers. Conclusion: Our meta-analysis suggested that increasing dietary LA intake does not have a significant effect on the blood concentrations of inflammatory markers. However, the extent of change in dietary LA intake might affect the effect of LA supplementation on CRP.

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.

Background ARA and DHA share the same synthetic pathway. FADS2 encodes the 1st step of the synthesis in mammals. Minor alleles of SNP in the human FADS2 region are associated with low serum ARA and DHA, indicating low capacity of synthesis. Objective Investigate the interaction between Fads2 genotypes and the ratio of dietary precursors, linoleic acid (LA) to α-linolenic acid (ALA), in ARA and DHA synthesis using heterozygous Fads2-null mice as a model of minor alleles of human FADS2. Method Fads2+/+ (WT) and Fads2+/- (HET) mice were fed one of the following for 3 months (n=6 each): 7% fat from flaxseed oil + canola oil (FCO), soybean oil (SO) or corn oil (CO) with LA/ALA at 1/1, 7/1 and 44/1, respectively. Result In WT liver, Fads2, Fads1 and Elovl2 mRNA was higher in CO than in FCO and SO. The same dietary effects were observed on Fads1 and Elovl2 mRNA in HET liver, whereas Fads2 mRNA was about half of that in WT in both HET liver and brain. Fads1 mRNA was higher in HET liver than in WT when fed FCO or SO. In both WT and HET, ARA in liver and gastrocnemius muscle of CO was more than 2X compared with FCO, whereas brain ARA and DHA were similar in all dietary groups. Although genotypes showed little effects on tissue ARA, 20:3 n6 was consistently lower in HET compared to WT in all tissues. The gene expression of inflammatory cytokines, IL1B, IL6 and TNFα, was unaffected by either diets or genotypes in liver and brain. Conclusion High dietary LA/ALA greatly increased the tissue ARA in both genotypes most likely due to high substrate as well as the compensatory induction of synthetic pathway to maintain DHA synthesis. In HET, compensatory induction of downstream Fads1 maintained tissue ARA and DHA close to WT. Support China Scholarship Council; USDA ILLU-971-365