The occurrence of trans-18:1 isomers in plasma lipids classes in humans

Abstract

Objective: The aim of this study was to examine the distribution of trans fatty acids (TFA) in plasma lipid classes and the relationship with dietary intake of TFA. Design: After a 2 week baseline (habitual) diet, all subjects consumed a moderate fat (MF) diet for 3 weeks with the fat being derived mainly from margarine and the rest from lean beef, and then a very low fat (VLF) diet for 3 weeks with the TFA being derived only from the lean beef. Blood samples were collected 2 days prior to the end and also on the last day of each dietary period. Setting: Deakin Institute of Human Nutrition, Deakin University, Geelong, Australia. Subjects: Ten free-living mildly hypercholesterolaemic subjects aged 22 ± 66 were recruited in Geelong. Outcome measures: TFA intake was calculated from analyses of Australian margarines, butter, lean meat and animal fat. The TFA in plasma lipid fractions were separated by AgNO 3 thin-layer chromatography and quantitated by capillary gas ± liquid chromatography using internal standards. Results: The phospholipid (PL) fraction contained more than 60% of the trans-18:1 isomers in the plasma lipids in all subjects. On the baseline diet, the predominant positional isomer of trans-18:1 in PL was D11, whereas in the other lipid classes it was the D9 isomer. The concentration of the D9 isomer increased on the MF diet, particularly in the PL fraction, while the concentration of the D11 isomer decreased in all fractions. On the VLF diet, the total TFA level decreased by approximately 50%, mainly due to decreases in the TFA isomers in the PL and TG fractions. Changes in plasma total and PL TFA, PL D9, D10 and D11 were strongly correlated with dietary TFA intake (P`0.0001). There were also signi®cant association between dietary TFA intake and PL D12 (P 0.003), triacylglycerol D9 (P 0.009), D11 (P 0.0005), total triacylglycerol (P 0.023) and free fatty acid TFA (P 0.042). Conclusions:The results suggest that the measurement of trans-18:1 in plasma PL and TAG, and plasma total TFA could be used to estimate the intake of TFA. Sponsorship: Meat Research Corporation of Australia. Descriptors: trans fatty acid; metabolism; plasma lipid classes; dietary trans fatty acid intake

Effects of margarine and butter consumption on distribution of trans‐18∶1 fatty acid isomers and conjugated linoleic acid in major serum lipid classes in lactating women

“…However, very few studies have reported the individual TFA isomers in plasma, let alone in each lipid fraction (29,30). We recently reported (31) a combination of methods that could be used to methylate the CLA content of various plasma lipid fractions.…”

F2-isoprostanes are correlated with trans fatty acids in the plasma of pregnant women

“…Dietary intake of TFA can be estimated based on the TFA levels in plasma phospholipids [40,[42][43][44][45]. Besides, the impact of a mild oxidative event like a typical pregnancy [24][25][26][27] on TFA generation remains to be determined.…”

Natural Rumen‐Derived trans Fatty Acids Are Associated with Metabolic Markers of Cardiac Health

“…Also, plasma phospholipid fatty acids reflect short-term dietary fat intake (1-2 weeks) compared to erythrocyte membrane phospholipids (1-2 months) or adipose tissue fatty acids (years) [54]. However, it has been shown that plasma phospholipid TFA may be used to estimate TFA intake [55]. Although capillary GC is a commonly used method for the determination of TFA, this technique also has its own limitations related to transesterification and temperature settings [56].…”