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Objectives Trans-fatty acids (TFA) are geometric isomers of naturally occurring cis-fatty acids, formed industrially through partial hydrogenation of vegetable oils or naturally in ruminant animals. TFA intake has been associated with risk factors for cardiovascular disease; therefore, reduced TFA consumption is a major public health objective. Food intake studies have provided estimates for TFA levels in the U.S. and we previously assessed TFA blood concentrations in fasting U.S. adults in the National Health and Nutrition Examination Survey (NHANES), finding an average 54% decrease in TFA between 1999-2000 and 2009-2010. The aim of this study was to determine nationally representative estimates for plasma TFA concentrations in children in the U.S. population. Methods We used the CDC isotope dilution-gas chromatography-negative chemical ionization-mass spectrometry (ID-GC-NCI-MS) method to quantitate four major TFA, palmitelaidic acid, elaidic acid, trans-vaccenic acid, and linoelaidic acid, in a nationally representative group of children in the U.S. population using NHANES samples. TFA were derivatized with pentafluorobenzyl-bromide and analyzed by GC-MS in selected ion monitoring mode using NCI with methane reagent gas. Separation was carried out on a Select FAME 200 m column with hydrogen carrier gas. The TFA limits of detection ranged from 0.02 μM to 0.43 μM. The intraday and inter-day % coefficients of variation ranged from 1-11% CV and 6-15% CV respectively. The mean accuracy for all four TFA was 102% (95% CI: 98%-107%). Results The TFA were measured in 916 participants (age: 6-19 years) from NHANES 1999-2000 and 1718 participants (age: 3-19 years) from NHANES 2009-2010, and were detected in all samples. Geometric means for the sum of the 4 TFAs were 80.7 μmol/l (95% CI: 74.6-87.3 μmol/L) and 30.6 μmol/l (95% CI: 29.0-32.3 μmol/L) in the NHANES 1999-2000 and 2009-2010, respectively. Overall TFA concentrations were 62% lower in NHANES 2009-2010 compared to 1999-2000. Conclusions TFA levels in children in the U.S. population are notably lower in NHANES 2009-2010 compared to NHANES 1999-2000 suggesting an overall reduction of TFA levels in children. Funding sources N/A.

Objectives. To estimate the impact of the 2006 policy restricting use of trans fatty acids (TFAs) in New York City restaurants on change in serum TFA concentrations in New York City adults. Methods. Two cross-sectional population-based New York City Health and Nutrition Examination Surveys conducted in 2004 (n = 212) and 2013–2014 (n = 247) provided estimates of serum TFA exposure and average frequency of weekly restaurant meals. We estimated the geometric mean of the sum of serum TFAs by year and restaurant meal frequency by using linear regression. Results. Among those who ate less than 1 restaurant meal per week, geometric mean of the sum of serum TFAs declined 51.1% (95% confidence interval [CI] = 42.7, 58.3)—from 44.6 (95% CI = 39.7, 50.1) to 21.8 (95% CI = 19.3, 24.5) micromoles per liter. The decline in the geometric mean was greater (P for interaction = .04) among those who ate 4 or more restaurant meals per week: 61.6% (95% CI = 55.8, 66.7) or from 54.6 (95% CI = 49.3, 60.5) to 21.0 (95% CI = 18.9, 23.3) micromoles per liter. Conclusions. New York City adult serum TFA concentrations declined between 2004 and 2014. The indication of greater decline in serum TFAs among those eating restaurant meals more frequently suggests that the municipal restriction on TFA use was effective in reducing TFA exposure. Public Health Implications. Local policies focused on restaurants can promote nutritional improvements.

Trans-fatty acids (TFA) are geometric isomers of naturally occurring cis-fatty acids. High dietary TFA intake has been associated with risk factors for cardiovascular disease. However, little is known about TFA levels in humans. To address this data need, we developed and validated a new isotope dilution-gas chromatography-negative chemical ionization-mass spectrometry (ID-GC-NCI-MS) method for quantitation of 27 fatty acids (FA) including 4 major TFA in human plasma, serum, and red blood cells (RBC) from 66 donors. Quantitation was performed with 18 isotope labeled internal standards and results are presented in µM and % of total FA. This method has high sensitivity and specificity due to use of pentafluorobenzyl-bromide derivatization combined with NCI-MS and a 200 m column to optimize positional and geometric FA isomer separation. The four major TFA, palmitelaidic acid, elaidic acid, trans-vaccenic acid, and linoelaidic acid, were detected in all samples, with median total TFA concentrations of 17.7 µM in plasma, 19.6 µM in serum, and 21.5 µM in RBC. The % of total FA for the TFA was 0.20% in plasma, 0.20% in serum, and 0.30% in RBC. Patterns for % FA are similar to those reported in other studies. We developed a highly specific, ID-GC-NCI-MS method to quantitate TFA and other FA in humans.

The lack of suitable biomarkers of oxidative stress is a common problem for antioxidant intervention studies in humans. We evaluated the efficacy of vitamin C supplementation in decreasing biomarkers of lipid peroxidation in nonsmokers and in cigarette smokers, a commonly studied, free-living human model of chronic oxidative stress. Participants received ascorbic acid (500mg twice per day) or placebo for 17 days in a double-blind, placebo-controlled, randomized crossover design study. The urinary biomarkers assessed and reported herein are derived from 4-hydroperoxy-2-nonenal (HPNE) and include the mercapturic acid (MA) conjugates of 4-hydroxy-2(E)-nonenal (HNE), 1,4-dihydroxy-2(E)-nonene (DHN), and 4-oxo-2(E)-nonenol(ONO). Vitamin C supplementation decreased the urinary concentrations of both ONO-MA (p=0.0013) and HNE-MA (p=0.0213) by ~30%; however, neither cigarette smoking nor sex affected these biomarkers. In contrast, vitamin C supplementation decreased urinary concentrations of DHN-MA (three-way interaction p=0.0304) in nonsmoking men compared with nonsmoking women (p

The breakdown of polyunsaturated fatty acids (PUFAs) under conditions of oxidative stress results in the formation of lipid peroxidation (LPO) products. These LPO products such as 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) can contribute to the development of cardiovascular and neurodegenerative diseases and cancer. Conjugation with glutathione, followed by further metabolism to mercapturic acid (MA) conjugates, can mitigate the effects of these LPO products in disease development by facilitating their excretion from the body. We have developed a quantitative method to simultaneously assess levels of 4-oxo-2-nonen-1-ol (ONO)-MA, HNE-MA, and 1,4-dihydroxy-2-nonene (DHN)-MA in human urine samples utilizing isotope-dilution mass spectrometry. We are also able to detect 4-hydroxy-2-nonenoic acid (HNA)-MA, 4-hydroxy-2-nonenoic acid lactone (HNAL)-MA, and 4-oxo-2-nonenoic acid (ONA)-MA with this method. The detection of ONO-MA and ONA-MA in humans is significant because it demonstrates that HNE/ONE branching occurs in the breakdown of PUFAs and suggests that ONO may contribute to the harmful effects currently associated with HNE. We were able to show significant decreases in HNE-MA, DHN-MA, and total LPO-MA in a group of seven smokers upon smoking cessation. These data demonstrate the value of HNE and ONE metabolites as in vivo markers of oxidative stress.