Search

Background and Aims: Blood lipid fractions serve as objective biomarkers of dietary fat intake. It is unclear which fatty acid pool most accurately reflects the dietary intakes of different n-3 PUFAs. We aimed to investigate the effect of fish and camelina sativa oil (CSO) intakes on fatty acid composition of erythrocyte membranes (EM), plasma phospholipids (PL), cholesteryl esters (CE) and triglycerides (TG). We also aimed to identify the most appropriate blood lipid fraction for assessing n-3 PUFA intake.Methods and Results: Altogether 79 volunteers with impaired glucose metabolism were randomly assigned either to CSO, fatty fish, lean fish or control groups for 12 weeks. Fatty acid compositions of lipid pools were measured by gas chromatography. The proportion of alpha-linolenic acid (ALA) increased in all lipid pools in the CSO group (false discovery rate (FDR) p < 0.001 for all). Similarly, the proportions of EPA and DHA increased in all lipid fractions in the fatty fish group (FDR p < 0.001 for EM, PL and CE; FDR p = 0.005 for TG; FDR p < 0.001 for EM, PL, CE; FDR p < 0.007 for TG, respectively). Changes in the dietary intakes of ALA, EPA and DHA correlated with the changes in their proportions in all lipid pools (r = 0.3-0.5, p < 0.05).Conclusion: There is no difference in the ability of blood lipid fractions in reflecting the dietary intake of different n-3 PUFAs over a time period of 12 weeks in subjects with high baseline omega-3 index. This trial was registered in Clinicaltrials.gov (NCT01768429). [ABSTRACT FROM AUTHOR]

Background and aims: Whole-grain cereals and diets with a low glycemic index may protect against the development of type 2 diabetes and heart disease, but the mechanisms are poorly understood. We studied the effect of carbohydrate modification on serum metabolic profiles, including lipids and branched chain amino acids, and dependencies between these and specific gene expression pathways in adipose tissue. Methods and results: Twenty subjects with metabolic syndrome were selected from the larger FUNGENUT study population, randomized either to a diet high in oat and wheat bread and potato (OWP) or rye bread and pasta (RP). Serum metabolomics analyses were performed using ultra-performance liquid chromatography coupled to electrospray ionization mass spectrometry (UPLC/MS), gas chromatography (GC) and UPLC. In the OWP group multiple proinflammatory lysophosphatidylcholines increased, while in the RP group docosahexaenoic acid (DHA 22:6n-3) increased and isoleucine decreased. mRNA expression of stress reactions- and adipose tissue differentiation-related genes were up-regulated in adipose tissue in the OWP group. In the RP group, however, pathways related to stress reactions and insulin signaling and energy metabolism were down-regulated. The lipid profiles had the strongest association with the changes in the adipose tissue differentiation pathway when using the elastic net regression model of the lipidomic profiles on selected pathways. Conclusion: Our results suggest that the dietary carbohydrate modification alters the serum metabolic profile, especially in lysoPC species, and may, thus, contribute to proinflammatory processes which in turn promote adverse changes in insulin and glucose metabolism. [Copyright &y& Elsevier]