Plasma Trans-Fatty Acid Levels in Fasting Adults from the National Health and Nutrition Examination Survey

摘要

Abstract: Trans-fatty acids (TFA) are geometric isomers of naturally occurring cis-fatty acids, formed industrially via partial hydrogenation of vegetable oils or naturally in ruminant animals. High dietary TFA intake results in increased low density lipoprotein levels and has been associated with other risk factors for cardiovascular disease. Due to these adverse health effects, reduction of TFA consumption is a major public health objective. Food intake studies have provided estimates for TFA levels in the U.S. population; however, little is known about the TFA levels in humans. We developed and validated a new isotope dilution-gas chromatography-negative chemical ionization-mass spectrometry method for the quantitation of 27 FA including four major TFA in 100 μl of human plasma. FA were derivatized with pentafluorobenzyl-bromide, resolved on a 200 m Select-FAME column with hydrogen as the carrier gas, and analyzed in selected ion monitoring mode using negative chemical ionization. The limits of detection were 0.07 μM for palmitelaidic acid, 0.28 pM for elaidic acid, 0.43 μM for trans-vaccenic acid, and 0.02 μM for linoelaidic acid. The intraday and inter-day percent coefficients of variation ranged from 1-11%CV and 6-15%CV respectively. The mean accuracy for all four TFA was 102% (95%Cl: 98%-107%). We used this method to quantitate four major TFA, palmitelaidic acid, elaidic acid, trans-vaccenic acid, and linoelaidic acid, in a nationally representative group of fasted adults in the U.S. population using National Health and Nutrition Examination Survey samples. The TFA were measured in 1613 participants from NHANES 1999-2000 and 2462 participants from NHANES 2009-2010, and were detected in all samples. Geometric means for the sum of the 4 TFAs were 80.9 pmol/l (95% Cl: 75.7, 86.5 umol/L) and 37.4 pmol/l (95% Cl: 36.1, 38.8 umol/L) in the NHANES 1999-2000 and 2009-2010, respectively. Overall TFA concentrations were 54% lower in NHANES 2009-2010 compared to 1999-2000.